Climate review and Experimental Long Range Forecast for SW England. June 2023.

Published 20 June 2023.

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A: Overview

1. Influences.

Changes in sea temperature

Sea temperature anomalies in most of the North Atlantic remain warmer than climatology for the middle of June. Areas around the UK, western Europe, western Mediterranean and the Baltic show 3 to 5 Celsius anomalies. Pacific Ocean anomalies along the equator show established El Nino state. The extent of the cold anomaly to the west of North America has increased in size a little. Temperatures in the NE of the Adriatic sea show a cold anomaly following the very severe cyclonic storm storm Biparjoy which brought flooding to parts of N India over recent days.

Biparjoy made landfall on June 16 near Naliya, India, with sustained winds of 95 km/h (60 mph) having weaken prior to landfall but continued to produced heavy rains as the weakening storm moved east for several days. Almost 180,000 people in Pakistan/India were evacuated. Final damage and casualty numbers are not yet available but so far 17 fatalities have been recorded.

The Atlantic Hurricane season for 2023 is just starting and there are currently two systems being monitored for development (Bret and 93L)

Confirmed tracks so far in 2023 are shown below. (Wikipedia)

Timeline: Arlene became a tropical storm but not a Hurricane. Bret and 93L are forecast to be tropical storms but it is not certain they whether one or both will develop further.

The Tropical Atlantic sea temperature anomalies are warmer than average, also at the higher end of the ensemble forecast from last month. Sea temperature in the tropical region are forecast to maintain similar anomalies through Autumn 2023. (see Met Office graphic below).

Ttropical Pacific Sea Surface Temperatures (Nino3.4) are in an El Nino state and forecast to remain so into 2024. This may result in a higher global average temperature for 2023 and there are suggestions that over the next few years the global temperature average will set a new record.

The effects of the El-Nino may be difficult to predict due to the excessive heat in water around coastal western Europe.

The North Atlantic Oscillation index (500hPa index shown below) became positive again around the 17th of June forecast to turn to neutral state over the next few weeks. Affects on the UK area are inconclusive for a neutral state.

See https://www.metoffice.gov.uk/weather/learn-about/weather/atmosphere/north-atlantic-oscillation

2. Recent Climatology

Recent WMO publication “State of the Climate in Europe 2022” shows how Europe has been warming twice as much as the global average since the 1980s, with far-reaching impacts on the region’s socio-economic fabric and ecosystems. In 2022, Europe was approximately 2.3 °C above the pre-industrial (1850-1900) average used as a baseline for the Paris Agreement on climate change.

SW England

June to the 19th the average temperature was between 16 and 18 Celsius, that’s 2 to 3 degrees Celsius above average. Rainfall was largely below 10mm in most places but overnight rain 19/20th and heavy thundery showers across northern parts of SW England will have locally increased totals.

Afternoon radar image 20th + show thunderstorms.

UK:

Met Office provisional Temperature and Rainfall anomalies for 2023 March April May are shown below. Temperatures in most areas were above average. Rainfall was above average. in most places hence it is shocker that hosepipe bans are require although there has been climate data showing increased run off rather than retention of water in the soils.

The 1981-2010 anomalies are no longer available on the Met Office site so will be using 1991-2020 graphics in future. Note that due to the rises in temperature decade on decade the April value shows as above average compared to 1961 to 1990 but near average when using the higher averages in the 30 years to 2020. Rainfall shows a similar trend suggesting rainfall amounts (30 year average) have increased decade on decade so that averages are higher and hence above average values harder to achieve at least early in the 30 year comparison period (assuming increases continue).

Copernicus, European sourced temperature and rainfall anomalies for May 2023 and the 12 months to the end of May compared with the 30 year period 1991-2020, are shown below:

UK River flows and ground water levels in May 2023 can be found in the 2023 Hydrological Summary

River flow across SW England were above average in May 2023. River flow data for the 15th of June from the UK Water Resources Portal shows well below normal river flows following the recent dry and hot weather.

Reservoir levels, according to SW Water remain below the long term average across SW England as of 15th June 2023 mainly due to Colliford and Roadford being only 70% full despite above average rainfall over Winter and Spring!. Consequently hosepipe bans remain in force across Cornwall and much of Devon.

The Global Flood Awareness System – GloFAS – forecast from June 1st to end of September 2023 shows a “normal” flood risk across SW England – does not cover flash flooding from for example thunderstorms.

B: Forecast data:

1. Stratosphere:

The polar vortex remains in summer mode as shown by the GFS 19/0600UTC analysis at 10hPa

2. Upper troposphere:

CFSv2 200hPa contours (top row) and CFSv2 anomaly (lower row) for July August September 2023.

3. Lower Troposphere:

A selection of model solutions for July to September 2023 using June data are shown below. The full set, including available graphics for Autumn 2023 can be found at https://www.weather-info.co.uk/wxsvc/seaslatest.html

Top row temperature anomaly. Lower row precipitation anomaly

July to September 2023

NASA EU area not available.

Data from WMO:

Three month average anomaly followed by July August September 2023. Top row temperature anomaly and lower row precipitation anomaly.

WMO super ensemble (below) is a mean of data supplied by National Meteorological organisations across the globe. Because of the amount of data the output is a low resolution. Note rainfall anomalies show marked cancellation between wetter and drier solutions in some of the multi model ensembles.

Individual members of the WMO super ensemble are shown below.

Russia

Copernicus C3S multi model ensemble. Less models than used in the WMO version but at higher resolution. data is available on a month by month bases but this detail often proves unreliable especially with regards to precipitation so here just the three month average anomalies are shown. The C3S is the combined multi model ensemble.

C: Comparing previous output:

March to May 2023 – based on February 2023 data.

Observed data.

Temperature. above average when compared to 1961-1990 but near average 1991-2020 period

Rainfall. above average

Sunshine. above average except N Ireland

Pressure. near normal or slightly above, Below normal in March otherwise mostly above normal and strongly so in May.

Original Summary – 160223 –
Temperature : Strong indication for above average temperature values for Spring, although the size of the anomaly is less clear and values may be only slightly above average. Some hints at near average values in March due to possible colder spell for the S of England around Mid March but this is uncertain.
Rainfall: Slightly more models suggest below average rainfall for Spring but with a hint of above normal across the NW. Large spread of solutions with some suggest a wet March across the S and W of the UK. In the WMO superensemble works out near average as the wetter solutions cancel out with the drier ones.
Caution:
1: Due to large scale stratospheric warming out of the polar vortex there is increased uncertainty for the second half of March.
2: Large scale blocking with cold easterly types seem to only be forecastable about two weeks ahead.

Comment: Above average temperature forecast good (three month average). Rainfall poor buut suggestion of wetter March in south was good.

Scoring will attempt to state good, fair, poor or no signal.
Note du3 to averaging period in models hindcast being below closer to the 1991-2020 period this new period will after this period be used for verification.
1. Russia (WMO): Temp good . PPN poor.
2. USA – CFS2 : Temp good . PPN fair.
3. UKMO Contingency: Temp good . PPN fair.
4. UKMO : Temp good . PPN fair . PMSL fair
5. USA – IRI : Temp good. PPN poor .
6. KMA APCC : Temp good . PPN poor .
7. JMA : Temp good PPN fair . PMSL good
8. NMME : Temp good . PPN poor.
9. WMO multi : Temp good . PPN poor..
10. BCC : Temp good . PPN fair. .
11. NASA : Temp good . PPN poor .
12. CanSips : Temp good . PPN poor .
13. Copernicus Temp good . PPN poor . PMSL poor
14. CMCC Temp good . PPN poor . PMSL fair
15: DWD Temp good. PPN fair . PMSL fair
16. EC Temp good. PPN fair . PMSL fair
17 JMA Temp good. PPN poor . PMSL fair
18 UKMO Temp good . PPN fair . PMSL fair
19. MF Temp good. PPN poor . PMSL fair
20 NCEP Temp good . PPN fair . PMSL fair
21 ECCC Temp: poor . PPN poor . PMSL fair

WMO low res data:
WMO low Temp good . PPN poor .
BoM Temp good . PPN fair .
Can Temp good. PPN poor .
DWD Temp good. PPN fair .
KMA Temp good. PPN poot .
MOSC Temp fair . PPN fair .
WASH Temp good . PPN poor .
CMA Temp good. PPN poor .
ECMWF Temp good . PPN fair .
UK Temp good. PPN poor .
JMA Temp good. PPN poor
MF Temp good. PPN fair .
CMCC Temp good. PPN poor .
CPTEC Temp good. PPN poor.

D: Text Forecast for SW England

Remainder of Summer 2023 (July August)

Temperature: Overwhelming indication for above or well above average temperatures for the season and each month.

Rainfall: Mixed signals. Above average more likely than below average in northern and western parts of SW England, elsewhere normal perhaps below normal but could be made above normal by local thunderstorm rainfall. Uncertain as to whether above average rain relates to more wet days or just shorter spells of heavier rain with fewer wet days compared to average.

Summer climate: 1981 to 2010 average daily mean temperature 14 or 15°C in many areas to 16 or 17°C in main urban areas also locally east of the moors and more widely in Somerset. Maximum temperatures average 19 to over 21°C in similar areas. July often warmer than August. Average 1981 to 2010 rain 300mm over the moors, typically 200 to 250mm in many coastal and eastern areas. July often drier than August.

Autumn 2023 (September October November)

Temperature: Milder than average Autumn is most likely, consistent across models. Slightly reduced anomalies in November.

Rainfall: Probably wetter than average for the season. Month to month detail unreliable but suggestion of drier start and wetter October/November.

Autumn climate: 1981 to 2010 average mean temperature 11 or 12°C but nearer 10°C in rural areas. Maximum temperatures average 14 to 16°C. November normally colder than October which is colder than September. Average 1981 to 2010 rain 300 to 400mm, 600 to 800mm over the moors but east of the moors and in lowland Somerset more like 200 to 300mm. September often drier than October or November.

Winter (December 2023 January and February 2024) limited data

Milder than normal for the season and each month. Average or above average precipitation in December and then average perhaps below. Overall wetter than average season. Snowfall likely to be below average.

Winter Climate: 1981-2010 average temperature values for lowland areas 7°C in the West and 5°C in the East. Rainfall; Dec and Jan typically wetter than February. 1981-2010 Autumn average 300-400 mm lowlands but 200-300 mm areas to E of Dartmoor. Snow climatology less than 5 days lying snow over lowland areas 5 to 10 hills, say hills around 200 metre elevation – one in three years have no lying snow.

E: Caution.

Experimental Long Range Forecasts do not have a good success rate, especially with regards to precipitation. The models are good at predicting above average values but not for picking out a one off colder month. The data used for the above forecast summary can be seen at here.

The attempt at a Regional Forecast for SW England aims to test whether such a forecast of temperature and rainfall variation from average can be made using numerical model data available on the internet. The forecast should not be used for any other purpose. A brief verification summary for the UK and Eire is routinely published at http://www.weather-info.co.uk/wxsvc/Verification.html or Click here for the Teignmouth and Dawlish summary

F: References.

SST anomaly NOAA Remote Sens. 2014, 6(11), 11579-11606; doi:10.3390/rs61111579

IRI statistics: Mason, S.J. and L. Goddard, 2001: Probabilistic precipitation anomalies associated with ENSO. Bull. Amer. Meteor. Soc., 82, 619-638.

UK climate details see: http://www.metoffice.gov.uk/public/weather/climate/

NMME information: http://journals.ametsoc.org/doi/abs/10.1175/BAMS-D-12-00050.1

CFS2 info

GLOFAS Acknowledgement: Data were provided by the Global Flood Awareness System – GloFAS (http://www.globalfloods.eu/) of the European Commission Joint Research Centre and the European Centre for Medium-Range Weather Forecasts.
Reference: Alfieri, L., Burek, P., Dutra, E., Krzeminski, B., Muraro, D., Thielen, J., and Pappenberger, F.: GloFAS – global ensemble streamflow forecasting and flood early warning, Hydrol. Earth Syst. Sci., 17, 1161-1175, doi:10.5194/hess-17-1161-2013, 2013.

‘Copernicus Products’ as listed in the C3S or CAMS Service Product Specification or any other items available through an ECMWF Copernicus http://climate.copernicus.eu

International seasonal monthly data from WMO

Climate data from The Met Office UK and NCEP USA

Contains public sector information licensed under the Open Government Licence v3.0.

Climate review and Experimental Long Range Forecast for SW England. May 2023.

Published 20May 2023.

A: Overview

1. Influences.

Changes in sea temperature

Sea temperature anomalies in most of the North Atlantic remain warmer than climatology for the middle of May. Parts of the Adriatic and central Mediterranean Sea are cooler due to recent cyclonic activity which brought floods to parts of Italy. Pacific Ocean anomalies along the equator have warmed as part of the transition towards El Nino state and the extent of the cold anomaly to the west of North America has reduced in size a little. Temperatures in the Bay of Bengal show a cold anomaly following MOCHA the CAT 4/5 storm.

Storm MOCHA 9th to 15th May 2023. CAT 5 storm, sea temperature in Bay of Bengal prior to storm over 30C. Advance forecast of over 10 days for the development of the storm. Provisional death toll 463 over 100 missing.

Myanmar: More than 78,250 people evacuated from at-risk areas, including 18,800 internally displaced persons in Rakhine. The nation’s government preparations shelter stockpiled to accommodate 100,000 people. The World Food Programme (WFP) in Myanmar said it was preparing food and relief supplies to support over 400,000 people in Rakhine and nearby areas. According to the United Nations Office for the Coordination of Humanitarian Affairs (OCHA), Mocha was anticipated to reach Myanmar’s Rakhine state and northwest region, where six million people require humanitarian assistance and 1.2 million are displaced. The World Health Organization has positioned 500,000 water purification pills in Myanmar, along with additional supplies.

Bangladesh: By 14 May, approximately 1.27 million people evacuated from Cox’s Bazar and over 100,000 from Chittagong.

https://en.wikipedia.org/wiki/Cyclone_Mocha

The Tropical Atlantic sea temperature anomalies are warmer than average, also warmer than forecast, and are now forecast to maintain similar anomalies through Autumn 2023. (see Met Office graphic below).

Forecasts suggest that tropical Pacific Sea Surface Temperatures (Nino3.4) are now in an El Nino state and forecast to move to strong El Nino condition during the summer and autumn. This may result in a higher global average temperature for 2023 and there are suggestions that over the next few years the global temperature average will set a new record.

The North Atlantic Oscillation index (500hPa index shown below) became positive around the 12th May but is forecast to return to neutral or negative over the next few weeks. Affects on the UK area are inconclusive for a neutral state.

See https://www.metoffice.gov.uk/weather/learn-about/weather/atmosphere/north-atlantic-oscillation

2. Recent Climatology

SW England

May to the 19th average temperature between 12 and 13 Celsius, about 0.5C above average. Rainfall between about 50 and 70 mm (although thunderstorms locally brought 25mm or so across eastern parts of SW England on the 19th) which was above average for most places. (Drier weather for the latter parts of May could return this to average). Sunshine 90 to 120 hours has been slightly below average so far.

UK:

Met Office provisional Temperature and Rainfall anomalies for 2023 February March April are shown below. Temperatures in most areas were above average. The very dry February was offset to some extent by the wetter March and in the south of the UK also the wetter April.

Storm Noa on 12 April 2023 was the second named storm of the 2022/2023 storm season. The storm was named by Meteo-France and brought widespread gusts of over 50Kt around coastlines of England and Wales. This was an unusually severe storm for the time of year; the most significant April wind storm to affect England and Wales since April 2013.

The 1981-2010 anomalies are no longer available on the Met Office site so will be using 1991-2020 graphics in future. Note that due to the rises in temperature decade on decade the April value sho2s as above average compared to 1961 to 1990 but near average when using the higher averages in the 30 years to 2020. Rainfall shows a similar trend suggesting rainfall amounts (30 year average) have increased decade on decade.

Copernicus, European sourced temperature and rainfall anomalies for April 2023 and the 12 months to the end of April compared with the 30 year period 1991-2020, are shown below:

UK River flows and ground water levels in April 2023 can be found in the 2023 Hydrological Summary

River flow across SW England were above average in April 2023. River flow data for the 16th of May in the UK Water Resources Portal shows normal to above normal river flows

Reservoir levels, according to SW Water remain below the long term average across SW England as of 14th April 2023 mainly due to Colliford and Roadford being only 70% full despite above average rainfall over winter. Consequently hosepipe bans remain in force across Cornwall and much of Devon.

The Global Flood Awareness System – GloFAS – forecast from May1st to end of August 2023 shows an enhanced flood risk across SW England, S and SE England.

B: Forecast data:

1. Stratosphere:

Stratospheric warming event ended on 21st March 2023. The polar vortex remains very weak and is in summer mode as shown by the GFS 19/1200UTC analysis at10hPa

CFSv2 200hPa contours (top row) and CFSv2 anomaly (middle row) NMME anomaly (lower row) for May June July 2023. Anomalies suggest above normal heights and reduced Atlantic jet flow through May to July.

2. Upper troposphere:

CFSv2 200hPa contours (top row) and CFSv2 anomaly (lower row) for June July August 2023. Inconstant anomalies between CFS and the NMME ensemble suggest problems with rainfall forecast.

3. Lower Troposphere:

A selection of model solutions for June to August 2023 using May data are shown below. The full set, including available graphics for Autumn 2023 can be found at https://www.weather-info.co.uk/wxsvc/seaslatest.html

Top row temperature anomaly and lower row precipitation anomaly

June to August 2023

NASA EU not available.

Data from WMO:

Three month average anomaly followed by June July August. Top row temperature anomaly and lower row precipitation anomaly.

WMO super ensemble (below) is a mean of data supplied by National Meteorological organisations across the globe. Because of the amount of data the output is a low resolution. Note also rainfall anomalies show marked cancellation between wetter and drier solutions. (UKMO data missing).

Individual members of the WMO super ensemble are shown below.

Temperature:

Precipitation:

C: Comparing previous output:

February to April 2023 – based on January 2023 data, for the UK.

Observed data.

Temperature. above average (March and April near normal but above normal compared to earlier 30 year periods).

Rainfall. Scotland below elsewhere normal or above (Feb dry other months wet)

Sunshine. Below average

Pressure. above average (below in March)

Original Summary – 190123 – Main theme is for above average temperatures for the three months taken together. There is a hint that March could have nearer normal values. Precipiation near normal overall with a chance of below average in parts of south and above in parts of the N. However, February probably wetter than average esepecially in western exposures (hill snow especially in N), March could see more areas near or below average except perhaps the N. April uncertain probably near average. Caution: 1: Due to large scale stratospheric warming out of the polar vortex there is increased uncertainty for the second half of February and for March. At present the indications are for a mostly mild and unsettled period which could lead to an early Spring. 2: Large scale blocking with cold easterly types seem to only be forecastable about two weeks ahead.

Comment: Temperature forecast good. Precipitation forecast fair overall but did not get very dry (February) or very wet (March) months, again month to month detail unreliable.

Scoring will attempt to state good, fair, poor or no signal.
Revised order
1. Russia (MHC+MGO): Temp good . PPN poor .
2. USA – CFS2 : Temp good . PPN poor .
3. UKMO Contingency: Temp good . PPN poor.
4. UKMO : Temp good . PPN poor. PMSL fair
5. USA – IRI : Temp poor . PPN poor. .
6. KMA APCC : Temp good . PPN poor.
7. JMA : Temp good . PPN poor PMSL poor
8. NMME : Temp fair . PPN poor but good in NW .
9. WMO multi : Temp good . PPN fair.
10. BCC : Temp good . PPN poor.
11. NASA : Temp good . PPN poor.
12. CanSips : Temp good . PPN poor.
13. Copernicus Temp good . PPN fair . PMSL poor
14. CMCC Temp good . PPN fair . PMSL poor
15: DWD Temp good . PPN fair. PMSL poor
16. EC Temp good . PPN poor. PMSL poor
17 JMA Temp good . PPN fair . PMSL good
18 UKMO Temp good . PPN fair . PMSL poor
19. MF Temp good . PPN fair . PMSL poor
20 NCEP Temp good . PPN fair . PMSL poor
21 ECCC Temp: good . PPN poor. PMSL poor

WMO low res data:
BoM Temp good . PPN poor .
Can Temp good . PPN poor .
DWD Temp good . PPN poor .
KMA Temp good . PPN poor .
MOSC Temp poor . PPN poor .
WASH Temp good . PPN poor .
CMA Temp good . PPN poor .
ECMWF Temp good . PPN poor .
UK missing .
JMA Temp good . PPN poor
MF Temp good . PPN poor .
CMCC Temp good . PPN poor .
CPTEC Temp good . PPN good .

D: Text Forecast for SW England

Summer 2023 (June July August)

Temperature: Overwhelming indication for above average temperatures for the season and each month although some models suggest Scotland could be nearer normal and some models hint at nearer normal values elsewhere in June which looks fairly unlikely.

Rainfall: Very little consistency month to month. Slightly mod models suggesting above average rainfall across SW England than below average. Uncertain as to whether this is more wet days or just shorter spells of heavier rain with fewer wet days compared to average. Hint that July could have the higher rain totals.

Autumn 2023 (September October November) limited data.

Temperature: Milder than average Autumn is most likely, consistent across models.

Rainfall: Probably wetter than average for the season. Month to month detail unreliable.

Winter (December 2023 January and February 2024) very limited data

E: Caution.

F: References.

SST anomaly NOAA Remote Sens. 2014, 6(11), 11579-11606; doi:10.3390/rs61111579

IRI statistics: Mason, S.J. and L. Goddard, 2001: Probabilistic precipitation anomalies associated with ENSO. Bull. Amer. Meteor. Soc., 82, 619-638.

UK climate details see: http://www.metoffice.gov.uk/public/weather/climate/

NMME information: http://journals.ametsoc.org/doi/abs/10.1175/BAMS-D-12-00050.1

CFS2 info

‘Copernicus Products’ as listed in the C3S or CAMS Service Product Specification or any other items available through an ECMWF Copernicus http://climate.copernicus.eu

International seasonal monthly data from WMO

Climate data from The Met Office UK and NCEP USA

Contains public sector information licensed under the Open Government Licence v3.0.

Climate review and Experimental Long Range Forecast for SW England. April 2023.

Published 21April 2023.

A: Overview

1. Influences.

Changes in sea temperature

Sea temperature anomalies in most of the North Atlantic remain warmer than climatology for the middle of April. Pacific Ocean anomalies along the equator have warmed as part of the transition towards El Nino state and the area of sea to thw west of North America has become relatively colder than average. The cold area to the NW of Australia probably stems from the recent CAT 4 storm in that area.

The Tropical Atlantic sea temperature anomalies remain slightly warmer than average and are forecast to maintain similar anomalies through to at least Autumn 2023. (see Met Office graphic below).

Forecasts suggest that tropical Pacific Sea Surface Temperatures (Nino3.4) are moving towards a strong El Nino condition. This may result in a higher global average temperature for 2023.

Met Office El Nino impact chart.

The North Atlantic Oscillation index (500hPa index shown below) has been trending negative recently and forecasts suggest a negative outlook through to the end of April. Negative values imply WEAKER westerly winds across the Atlantic towards Europe although a neutral or weak signal is inconclusive.

See https://www.metoffice.gov.uk/weather/learn-about/weather/atmosphere/north-atlantic-oscillation

2. Recent Climatology

SW England

Temperatures to 20th are running a fraction above average in western parts of the region and a fraction below in eastern parts. Rainfall has also been a little above average so far. Pressure has been a little higher than average with sunshine not far from average.

UK:

Met Office provisional Temperature and Rainfall anomalies for 2023 January, February and March are shown below. The higher rainfall in places during January and the very wet March period did go some way to recovering reservoir levels but clearly not yet enough for parts of Cornwall and Devon.

Copernicus, European sourced temperature and rainfall anomalies for March 2023 and the 12 months to the end of March compared with 30 year period 1981-2010, are shown below:

UK River flows and ground water levels in March 2023 can be found in the 2023 Hydrological Summary

River flow data is only available to the 10th of April in the UK Water Resources Portal, hence a recent graphic has not been included.

Reservoir levels, according to SW Water remain below the long term average across SW England as of 16th April 2023. Some of the reservoirs are at 100% capacity except in the N and W of the region, for details check SW Water website.

Due to low reservoir levels at Colliford and Roadford the hosepipe ban in Cornwall continues and is being extended to parts of Devon from the 25th April (see map below) despite the September to March rainfall being above average across most of SW England.

The Global Flood Awareness System – GloFAS – forecast from April 1st to end of July 2023 shows no enhanced flood risk.

The Global Flood Awareness System – GloFAS – forecast from March 1st to end of June 2023 shows neutral or reduced river flood risk.

B: Forecast data:

1. Stratosphere:

Temperature in the upper stratosphere over the N Pole at 30hPa and 10hPa are shown below.

Stratospheric warming event ended on 21st March 2023. The polar vortex is now very weak as shown by the GFS 21/0600UTC analysis at10hPa

3. Lower Troposphere:

A selection of model solutions for May to July 2023 using April data are shown below. The full set, including available graphics for Summer 2023 can be found at https://www.weather-info.co.uk/wxsvc/seaslatest.html

Top row temperature anomaly and lower row precipitation anomaly

May to July 2023

NASA missing.

Data from WMO:

Three month average anomaly followed by May June July. Top row temperature anomaly and lower row precipitation anomaly.

WMO super ensemble (below) is a mean of data supplied by National Meteorological organisations across the globe. Because of the amount of data the output is a low resolution. Note also rainfall anomalies show marked cancellation between wetter and drier solutions.

Individual members of the WMO super ensemble are shown below.

Exeter UKMO

Temperature:

Precipitation:

WMO super-ensemble for Summer 2023:

C: Comparing previous output:

January to March 2023 – based on December 2022 data, for the UK.

Observed data.

Temperature. Above normal overall and each month except for N Scotland which was colder in March.

Rainfall. For the UK as a whole rainfall was a tiny fraction below average, largely due to N Ireland and Scotland being drier on aggregate and Wales and England wetter.

Sunshine. Was slightly above aveage despite a cloudier than average March.

Pressure. on aggregate pressure above average (SW flow) due to High pressure in February which did not offset lower pressure in March.

Original Summary – 191222-

The overall signal for the three month period is for above normal temperatures, although some models suggest near average or slightly above. Met Office contingency, issued 19th, has a slightly increase in below average solutions for January although the majority are near average. Several other models hint at near average temperatures in January so another cold snap is possible before a milder end to winter. Precipitation very mixed indication with the wetter than average solutions balanced against the drier than average. Probably a drier (and colder spell in January) then near normal precipitation but with a chance of above in western exposures.

Comment: Temperature forecast was good for the three month average. Rainfall forecast of near average was good but did not indicate the very dry February and in the south the very March.

Scoring will attempt to state good, fair, poor or no signal for the three month overall.

Brazil and DWD made a stab at the drier Feb and wetter March also Moscow WMO hinted that way but given the very dry and very wet observed data these events were not reflected by the mean anomalies.
Non of the models got the colder March in N half of Scotland

1. Russia (WMO): Temp good . PPN fair .
2. USA – CFS2 : Temp good . PPN fair .
3. UKMO Contingency: Temp fair . PPN good .
4. UKMO : Temp good . PPN good . PMSL fair
5. USA – IRI : Temp good . PPN fair .
6. KMA APCC : Temp good . PPN no signal .
7. JMA : Temp good . PPN poor . PMSL fair
8. NMME : Temp good. PPN fair .
9. WMO multi : Temp good . PPN fair .
10. BCC : Temp good . PPN fair .
11. NASA : Temp good . PPN poor .
12. CanSips : Temp good. PPN fair.
13. Copernicus Temp good . PPN fair . PMSL fair
14. CMCC Temp good . PPN fair . PMSL poor
15: DWD Temp good . PPN fair . PMSL good
16. EC Temp good . PPN fair . PMSL good
17 JMA Temp good . PPN fair . PMSL fair
18 UKMO Temp good . PPN fair . PMSL fair
19. MF Temp good . PPN fair . PMSL fair
20 NCEP Temp good . PPN fair . PMSL fair
21 ECCC Temp: good . PPN fair . PMSL poor

WMO low res data:
BoM Temp good . PPN poor .
Can Temp good . PPN fair .
DWD Temp good . PPN good .
KMA Temp good . PPN poor .
MOSC Temp poor/fair . PPN fair .
WASH Temp good . PPN poor .
CMA Temp good . PPN poor .
ECMWF Temp good . PPN poor .
UK Temp good. PPN fair .
JMA Temp good . PPN poor
MF Temp good . PPN poor.
CMCC Temp good . PPN poor .
CPTEC Temp good . PPN fair.

D: Text Forecast for SW England

Remainder of Spring 2023 (May)

Temperature: Strong indication for above average temperature values.

Rainfall forecast very uncertain overall suggestion of average or above average. Above average more likely in western parts of the region. Number of models suggesting above average similar to those suggesting below.

Caution:
1: Large scale blocking with easterly types seem to only be forecastable about two weeks ahead.

May climate: 1981-2010 average mean temperature 11 or 12°C. Average May rainfall roughly 70mm but 150mm over moors and 40mm in drier east each month.

Summer 2023 (June July August)

Temperature: Likely to be above average for the season and each month.

Rainfall: Slightly more models suggest a drier than average season rather than a wetter than average season. Rainfall totals may be above average but with more dry days than average. Month to month data unreliable.

Autumn 2023 (September October November) limited data.

Temperature: Milder than average Autumn is most likely, consistent across models.

Rainfall: Probably wetter than average for the season. Month to month detail unreliable.

Winter (December 2023 January and February 2024) very limited data

Milder than normal with average or above average precipitation.

E: Caution.

Experimental Long Range Forecasts do not have a good success rate. especially with regards to precipitation. The models are good at predicting above average values but not for picking out a one off colder month. The data used for the above forecast summary can be seen at here.

F: References.

SST anomaly NOAA Remote Sens. 2014, 6(11), 11579-11606; doi:10.3390/rs61111579

IRI statistics: Mason, S.J. and L. Goddard, 2001: Probabilistic precipitation anomalies associated with ENSO. Bull. Amer. Meteor. Soc., 82, 619-638.

UK climate details see: http://www.metoffice.gov.uk/public/weather/climate/

NMME information: http://journals.ametsoc.org/doi/abs/10.1175/BAMS-D-12-00050.1

CFS2 info

‘Copernicus Products’ as listed in the C3S or CAMS Service Product Specification or any other items available through an ECMWF Copernicus http://climate.copernicus.eu

International seasonal monthly data from WMO

Climate data from The Met Office UK and NCEP USA

Contains public sector information licensed under the Open Government Licence v3.0.

Climate review and Experimental Long Range Forecast for SW England. March 2023.

Published 19 March 2023.

A: Overview

1. Influences.

Changes in sea temperature

Sea temperature anomalies in most of the Northern Hemisphere remain warmer than climatology for the middle of March. Pacific Ocean anomalies have warmed along the equator as the La Nina decays and transitions towards El Nino state. The South China Sea along with the West coast of North America show below normal anomalies.

The Tropical Atlantic sea temperature anomalies remain slightly warmer than average and are forecast to maintain similar anomalies through Spring and Summer 2023. (see Met Office graphic below).

Forecasts suggest that tropical Pacific Sea Surface Temperatures (Nino3.4) are moving towards El Nino conditions as previously forecast. This may aid higher global average temperatures for 2023.

The North Atlantic Oscillation index (500hPa index shown below) has been neutral recently and forecast to remain neutral through March. Negative values imply WEAKER westerly winds across the Atlantic towards Europe although a neutral or weak signal is inconclusive.

See https://www.metoffice.gov.uk/weather/learn-about/weather/atmosphere/north-atlantic-oscillation

2. Recent Climatology

SW England

Up to the 18th of February, the average temperature has been around 7.5C which is near or slightly below average. Rainfall has been above average for the month so far with totals 50 to 90mm, most of which fell after the 7th. Sunshine has been bellow average.

UK:

Met Office provisional Temperature and Rainfall anomalies for 2022 December, 2023 January and February are shown below. The higher rainfall in places during the November to January period did go some way to recovering reservoir levels at least in parts of the SW but the low rainfall in February has not helped further recovery. December was the only colder than average month of 2022 and for southern areas since August 2021.

Copernicus, European sourced temperature and rainfall anomalies for February2023 and the winter period December to February compared with 30 year period 1981-2010, are shown below.

“In February 2023, most of western Europe experienced below-average soil moisture, reaching more than 4% below average in many regions, and more than 8% below average in parts of Spain and Türkiye. Although not as low in magnitude as for Spain and Türkiye, the soil moisture levels in parts of Ireland, UK and France, were lower than in any previous February in the ERA5 soil moisture record from 1979 onwards.

The pronounced lack of precipitation along with above-average temperatures that led to such conditions was related to persistent anticyclonic conditions shielding the affected areas from weather disturbances.

According to the UK MetOffice, England had its eighth driest February in a series which goes back to 1836, and its driest since 1993, with an average of 15.3mm of rain. Météo France reported over 30 days without precipitation after the 21st of January for France; a record in a dataset going back to 1959. The current dryness of soils in France is untypical for February and rather expected in mid-April. Further evidence of the severity of the drought comes from the European Drought Observatory which, for the second 10-day period of the month, issued a warning based on the impact of the precipitation deficit on soil moisture for France, Belgium, most of the UK and Ireland, and an alert to highlight the fact that vegetation was also being affected, for much of Ireland and regions of Spain and Türkiye.” Source Copernicus.

UK River flows and ground water levels in February 2023 can be found in the 2023 Hydrological Summary

The exceptionally dry February resulted in very low river flows data on the 16th March reflects the recent wetter weather.

Reservoir levels, according to SW Water remain below the long term average across SW England as of 12th March 2023. Some of the reservoirs are at 100% capacity except in the N and W of the region, for details check SW Water website.

The Global Flood Awareness System – GloFAS – forecast from March 1st to end of June 2023 shows neutral or reduced river flood risk.

B: Forecast data:

1. Stratosphere:

Temperature in the upper stratosphere over the N Pole at 30hPa and 10hPa are shown below. Stratospheric warming has occurred and the polar vortex is now very weak.

Very weak polar stratospheric vortex, not quite summer mode as shown by GFS 10hPa plot 18th March 2023

2. Upper troposphere:

CFSv2 200hPa contours (top row) and CFSv2 anomaly (middle row) NMME anomaly (lower row) for and April May June 2023. Anomalies suggest above normal heights and reduced Atlantic jet flow through May and June.

3. Lower Troposphere:

A selection of model solutions for April to June 2023 using March data are shown below. The full set, including available graphics for Summer 2023 can be found at https://www.weather-info.co.uk/wxsvc/seaslatest.html

Top row temperature anomaly and lower row precipitation anomaly

April to June 2023

CFSv2 E3 data (above)

NMME

ECMWF

NASA

Data from WMO:

Three month average anomaly followed by April May June. Top row temperature anomaly and lower row precipitation anomaly.

WMO super ensemble (below) is a mean of data supplied by National Meteorological organisations across the globe. Because of the amount of data the output is a low resolution.

WMO super-ensemble

Individual members of the WMO super ensemble are shown below.

BCC China

BOM Australia

CMCC (Southern Europe)

CPTEC Brazil

DWD Germany

ECMWF low resolution

Canada CMA

Russia Moscow

Seoul KMA Korea

Tokyo JMA

Toulouse France

UKMO Exeter

Washington USA

WMO super-ensemble for Summer 2023:

Graphics for Summer 2023 can be found at https://www.weather-info.co.uk/wxsvc/seaslatest.html

C: Comparing previous output:

December 2022 to February 2023 – based on November 2022 data, for the UK.

Observed data

Temperature. Despite colder December the season had average or above average temperatures

Rainfall. Despite the exceptionally dry February some parts of the UK had above average rain although balanced by the larger area with below average

Sunshine. above average in S, elsewhere near average but below in N Ireland

Pressure. below normal in December but overall above average for season. H over S in February

Original Summary -18NOV2022 –
Temperature:
The main indication remains for above normal temperatures through the season and probably for each month. There are, however, a few more models suggesting nearer normal values in December (most likely in England) and recent Met Office monthly forecasts suggest a colder spell in December. The Met Office seasonal forecast issued late October also hinted at some colder spells but the most recent forecast indicates above normal values. Output from Russia (via WMO) suggests colder than average across England later in the winter but earlier Russian output (from Russian Met Service) was for above average. A caution is that over recent years models have not picked out a colder spell more than about two or three weeks ahead.
Precipitation: Forecast suggest below average in the south and perhaps above in the north but are not consistent month to month and are less reliable than temperature forecast. December and to a less extent February, have the biggest chance of being below average in the south. Snow risk likely to be lower than average for most areas except high ground.
Sea level pressure probably above average.

Comment: Good steer for above average overall and also the hints at a colder December. Rainfall signal for some areas drier than average and hint at drier February but not that strong a signal. Pressure forecast good.
Models did not pick out exceptionally dry February.

Scoring will attempt to state good, fair, poor or no signal for the three month averages.
Revised order
1. Russia (WMO): Temp fair. PPN fair .
2. USA – CFS2 : Temp good . PPN fair .
3. UKMO Contingency: Temp fair . PPN good .
4. UKMO : Temp good . PPN good . PMSL good
5. USA – IRI : Temp no signal . PPN no signal.
6. KMA APCC : Temp fair . PPN no signal .
7. JMA : Temp good. PPN fair . PMSL fair
8. NMME : Temp good . PPN fair.
9. WMO multi : Temp good. PPN good .
10. BCC : Temp fair. PPN fair .
11. NASA : Temp fair. PPN poor .
12. CanSips : Temp good . PPN fair.
13. Copernicus Temp good . PPN fair. PMSL good
14. CMCC Temp good . PPN fair. PMSL good
15: DWD Temp good . PPN good. PMSL good
16. ECMWF Temp good . PPN good. PMSL good
17 JMA Temp good . PPN fair. PMSL good
18 UKMO Temp good . PPN good. PMSL good
19. MF Temp good . PPN fair. PMSL good
20 NCEP Temp good. PPN fair . PMSL poor
21 ECCC Temp: good . PPN fair. PMSL good

WMO low res data:
BoM had the best shot at the drier February
BoM Temp good . PPN good .
Can Temp good . PPN good .
DWD Temp good . PPN fair .
KMA Temp good . PPN good .
MOSC Temp poor. PPN fair .
WASH Temp good . PPN poor .
CMA Temp good . PPN fair .
ECMWF Temp good . PPN good .
JMA Temp good . PPN fair
MF Temp good . PPN fair .
CMCC Temp good . PPN good .
CPTEC Temp good . PPN fair .

D: Text Forecast for SW England

Remainder of Spring 2023 (April May)

Temperature: Strong indication for above average temperature values with higher anomalies in May than in April.

Rainfall forecast very uncertain overall suggestion of average or above average,

Caution:
1: Large scale blocking with easterly types seem to only be forecastable about two weeks ahead.

Spring climate: 1981-2010 average mean temperature 9 or 10°C but a few degrees cooler over the moors. Roughly Apr 8 or 9°C May 11 or 12°C. Average 1981 to 2010 rain similar totals in April and May roughly 70mm but 150mm over moors and 40mm in drier east each month.

Summer 2023 (June July August) Limited data

Temperature: Likely to be above average for the season and each month.

Rainfall: Slightly more models suggest a drier than average season rather than a wetter than average sesason. Rainfall totals may be above average but with more dry days than average. A hint that August less likely to be a drier than average month though usually month to month detail unreliable.

Autumn 2023 (September October November) very limited data.

Temperature: Milder than average Autumn is most likely, consistent across models.

Rainfall: probably wetter than average for the season but some indication of a drier October, though monthly detail unreliable.

E: Caution.

F: References.

SST anomaly NOAA Remote Sens. 2014, 6(11), 11579-11606; doi:10.3390/rs61111579

IRI statistics: Mason, S.J. and L. Goddard, 2001: Probabilistic precipitation anomalies associated with ENSO. Bull. Amer. Meteor. Soc., 82, 619-638.

UK climate details see: http://www.metoffice.gov.uk/public/weather/climate/

NMME information: http://journals.ametsoc.org/doi/abs/10.1175/BAMS-D-12-00050.1

CFS2 info

‘Copernicus Products’ as listed in the C3S or CAMS Service Product Specification or any other items available through an ECMWF Copernicus http://climate.copernicus.eu

International seasonal monthly data from WMO

Climate data from The Met Office UK and NCEP USA

Contains public sector information licensed under the Open Government Licence v3.0.

Climate review and Experimental Long Range Forecast for SW England. February 2023.

Published 16 February 2023.

A: Overview

1. Influences.

Changes in sea temperature

Sea temperature anomalies in most of the Northern Hemisphere remain warmer than climatology for the middle of February. Baltic and Mediterranean temperatures remain well above normal. Pacific Ocean anomalies are similar in size to last month although the area of colder than average temperature in the East Pacific near the North American coast has increased again after a decrease last month.

The Tropical Atlantic sea temperature anomalies remain slightly warmer than average and are forecast to maintain similar anomalies through Spring and into summer 2023. (see Met Office graphic below).

Forecasts suggest that tropical Pacific Sea Surface Temperatures (Nino3.4) are likely to move to El Nino conditions from mid Spring 2023 which may help increase global average temperatures for 2023.

The North Atlantic Oscillation index (500hPa index shown below) has been marginally positive recently. The ensemble forecast is for neutral or slightly negative conditions by early March. Negative values imply WEAKER westerly winds across the Atlantic towards Europe although a neutral or weak signal is inconclusive.

See https://www.metoffice.gov.uk/weather/learn-about/weather/atmosphere/north-atlantic-oscillation

2. Recent Climatology

SW England

Up to the 16th of February, the average temperature has been between 6 and 8C in most areas which is about 1C to 1.5C above average. Rainfall has been well below average for the month so far with most parts recording less that 10% of normal rainfall and in many places totals are below 1mm. Even over hilly areas in W Devon and Cornwall rainfall has been low.

UK:

Met Office provisional Temperature and Rainfall anomalies for 2022 November December and 2023 January are shown below: The higher rainfall in places during the November to January period has gone some way to recovering reservoir levels at least in parts of the SW but the recent low rainfall will not help further recovery. December was the first colder than average month of 2022 and for southern areas since August 2021.

Copernicus, European sourced temperature and rainfall anomalies for January 2023 and the year to January compared with 30 year period 1981-2010, are shown below.

UK River flows and ground water levels in January 2023 can be found in the February 2023 Hydrological Summary

The wet weather at the end of 2022 meant that levels recovered in many parts of the SW during December and January. However the recent dry spell has once again reduced river flow rates as shown in the data from the nrfa.ceh.ac.uk UK water resource portal below:

Reservoir levels, according to SW Water remain below the long term average across SW England as of 12th February 2023. Some of the reservoirs are at 100% capacity except in the N and W of the region, for details check SW Water website.

The Global Flood Awareness System – GloFAS – forecast from February 1st to end of May 2023 shows neutral or reduced river flood risk.

B: Forecast data:

1. Stratosphere:

Temperature in the upper stratosphere over the N Pole at 19 and 30hPa is shown below. Stratospheric warming is under way having started later in January.

The stratosphere having been in winter mode is currently being disrupted (warmed out) and the patter of winds at these levels have deviated from average which could well be why the “Chinese Spy Balloon” ended up slower moving over the USA that would typically be the case. It is surprising that little mention has been made of the unusual wind patterns. Back trajectories are available to estimate to track of balloons at any specified level.

In the next 15 days further warming in likely – see GFS forecast below.

The warming out of the polar stratospheric vortex may lead to a reversal of the stratospheric winds or a jump into “summer mode” although extended (6 week) ECMWF products show some cooling in several weeks time and this may help refresh the vortex.

2. Upper troposphere:

CFSv2 200hPa contours (top row) and CFSv2 anomaly (middle row) NMME anomaly (lower row) for and March, April and May 2023. Anomalies suggest above normal highest and reduced Atlantic jet flow and consequently a less mobile weather pattern

3. Lower Troposphere:

A selection of model solutions for March to May 2023 using February data are shown below. The full set, including available graphics for Summer 2023 can be found at https://www.weather-info.co.uk/wxsvc/seaslatest.html

Top row temperature anomaly and lower row precipitation anomaly

March to May 2023

Data from WMO:

Three month average anomaly followed by March April May. Top row temperature anomaly and lower row precipitation anomaly.

WMO super ensemble (below) is a mean of data supplied by National Meteorological organisations across the globe. Because of the amount of data the output is a low resolution.

Individual members of the WMO super ensemble are shown below.

Russia Moscow – August temperature data looks to have a data error.

Graphics for Summer 2023 can be found at https://www.weather-info.co.uk/wxsvc/seaslatest.html

C: Comparing previous output:

November 2022 to January 2023 – based upon October 2022 data, for the UK.

Observed data:

Temperature. Thanks to the very mild November and despite the cold December the three month average works out at a little above normal.

Rainfall. Northern Ireland and parts of Scotland three month average below normal elsewhere above normal. Rainfall patterns a little messy with E Scotland probably above average and parts of NE England below average.

Sunshine. above average for three month period.

Pressure. below average (predominant SW flow) for three month period.

Forecast:

Full review data available here https://www.weather-info.co.uk/wxsvc/VerifNDJ2022.html

Original Summary -18OCT2022 –
Temperature: The mean over the three months is likely to be above average. One model (NASA) suggests normal with a hint of below normal in December and several models (not the majority) suggest that parts of England could see near normal values in December and a few suggest January could be near normal which would allow for an average number of frosts.
Precipitation: Very mixed indication but several models suggest below average precipitation for the season with the strongest signal being during January. Areas with above average most likely across the north and NW of UK which would be normal, but a small number also include the East of England in the risk. Snowfall probably below average (except for mountains) but with a risk of wintery showers more widespread in December Sea Level Pressure: Possibly higher than average (implies slightly less windy) but January could see below average values in the SW.

Comment: The indication from NASA for a colder December was correct and the hint from other that near normal values for December also pointed to a colder month BUT overall the three month value ended up above average. Precipitation not very helpful but idea of more wintry precipitation in Dec was OK. Pressure forecast misleading.

Scoring will attempt to state good, fair, poor or no signal for the three month average.
Revised order. Note although marked as good for above average temperature (3 month average) most did not get the colder December

1. Russia (WMO): Temp good. PPN poor .
2. USA – CFS2 : Temp good. PPN fair (earlier runs better) .
3. UKMO Contingency: Temp fair. PPN poor .
4. UKMO : Temp good. PPN no signal PMSL good
5. USA – IRI : Temp fair . PPN no signal .
6. KMA APCC : Temp good. PPN poor .
7. JMA : Temp good. PPN poor . PMSL poor
8. NMME : Temp good. PPN poor .
9. WMO multi : Temp good . PPN poor .
10. BCC : Temp good. PPN poor .
11. NASA : Temp fair. PPN fair .
12. CanSips : Temp good. PPN poor .
13. Copernicus Temp good . PPN poor . PMSL poor
14. CMCC Temp good . PPN poor . PMSL poor
15: DWD Temp good . PPN poor . PMSL poor
16. EC Temp good . PPN poor . PMSL poor
17 JMA Temp good . PPN poor . PMSL poor
18 UKMO Temp good . PPN poor . PMSL poor
19. MF Temp good . PPN poor . PMSL poor
20 NCEP Temp good . PPN poor . PMSL poor
21 ECCC Temp: good . PPN poor . PMSL poor

WMO low res data: Three month average only.
BoM Temp good . PPN poor .
Can Temp good . PPN poor .
DWD Temp good . PPN poor .
KMA Temp fair . PPN poor .
MOSC Temp good . PPN poor .
WASH Temp good . PPN good.
CMA Temp good . PPN poor .
ECMWF Temp good . PPN poor .
UK Temp good . PPN poor .
JMA Temp good . PPN poor
MF Temp good. PPN poor .
CMCC Temp good . PPN poor .
CPTEC Temp good . PPN poor .

D: Text Forecast for SW England

Spring 2023 (March April May)

Strong indication for above average temperature values for Spring, although the size of the anomaly is less clear. Some hints that there could be a colder spell around the middle or late March linked to changes in the stratosphere but uncertain. Rainfall forecast very uncertain overall suggestion of average or below average rainfall BUT some models suggest a wetter than average March.

Caution:
1: Due to large scale stratospheric warming out of the polar vortex there is increased uncertainty for the second half of March.
2: Large scale blocking with cold easterly types seem to only be forecastable about two weeks ahead.

Spring climate: 1981-2010 average mean temperature 9 or 10°C but a few degrees cooler over the moors. Roughly Mar 7 or 8°C Apr 8 or 9°C May 11 or 12°C. Average 1981 to 2010 rain 200 to 300mm lowest values in E Devon and over parts of Somerset

Summer 2023 (June July August) Limited data

Temperature likely to be above average for the season and each month. Rainfall uncertain, near or above average overall but despite this number of rain days could be below average.

Autumn 2023 (September October November) very limited data.

Milder and wetter than average for the season and each month.

E: Caution.

F: References.

SST anomaly NOAA Remote Sens. 2014, 6(11), 11579-11606; doi:10.3390/rs61111579

IRI statistics: Mason, S.J. and L. Goddard, 2001: Probabilistic precipitation anomalies associated with ENSO. Bull. Amer. Meteor. Soc., 82, 619-638.

UK climate details see: http://www.metoffice.gov.uk/public/weather/climate/

NMME information: http://journals.ametsoc.org/doi/abs/10.1175/BAMS-D-12-00050.1

CFS2 info

‘Copernicus Products’ as listed in the C3S or CAMS Service Product Specification or any other items available through an ECMWF Copernicus http://climate.copernicus.eu

International seasonal monthly data from WMO

Climate data from The Met Office UK and NCEP USA

Contains public sector information licensed under the Open Government Licence v3.0.

Climate review and Experimental Long Range Forecast for SW England. January 2023.

Published 20 January 2023.

A: Overview

1. Influences.

Changes in sea temperature

Sea temperature anomalies in most of the Northern Hemisphere remain warmer than climatology for the middle of January. Baltic and Mediterranean temperatures remain well above normal. Pacific Ocean anomalies are similar in size to last month although the area of slightly colder than average temperature in the East Pacific near the North American coast has slightly reduced anomalies..

Antarctic anomalies showing positive values near 150 deg W.

The Tropical Atlantic sea temperature anomalies remain slightly warmer than average and are forecast to maintain similar anomalies through Spring and into early summer 2023. (see Met Office graphic below).

Forecasts suggest that tropical Pacific Sea Surface Temperatures (Nino3.4) are likely to move to El Nino conditions from late Spring 2023 which may help increase global average temperatures for 2023.

The North Atlantic Oscillation index (500hPa index shown below) has been marginally positive recently. The ensemble forecast is for neutral or slightly negative conditions. Negative values imply WEAKER westerly winds across the Atlantic towards Europe although a neutral or weak signal is inconclusive.

See https://www.metoffice.gov.uk/weather/learn-about/weather/atmosphere/north-atlantic-oscillation

The negative NAO phase represents the reverse with a weaker than usual difference in pressure.

Winds from the east and north-east are more frequent, bringing with them cold air, while the adjusted position of the jet stream leads to weaker and less frequent storms. Consequently, Europe and eastern US are more likely to experience cold, calm and dry winters. In contrast, northern Canada and Greenland will tend to be mild and wet.

2. Recent Climatology

SW England

Up to the 19th of January, despite the recent cold days, the average temperature has been between 7 and 9C in most areas which is about 1.5C above average. This anomaly may well reduce given lower than average values for at least parts of the remainder of January. Rainfall has been above average for the month already and over the last few days there has been some snow in places, especially over the moors and across parts of Cornwall

UK:

Met Office provisional Temperature and Rainfall anomalies for October November December and the Year 2022 are shown below: The higher rainfall in places during November has gone some way to recovering reservoir levels in Cornwall although northern parts of the region were less wet than southern parts. December was the first colder than average month of 2022 and for southern areas since August 2021.

Copernicus, European temperature and rainfall anomalies for December 2022 and the year (Jan to Dec 2022) compared with 30 year period 1981-2010, are shown below..

UK River flows and ground water levels in December 2022 can be found in the January 2023 Hydrological Summary

Recent wet weather meant that levels recovered in many parts of the SW during December and in January. Data from the nrfa.ceh.ac.uk UK water resource portal shown below:

Reservoir levels, according to SW Water remain below the long term average across SW England as of 15th January 2023. Some of the reservoirs are at 100% capacity except in the N and W of the region, for details check SW Water website.

The Global Flood Awareness System – GloFAS – forecast from January 1st to end of April 2023 shows an elevated river flood risk in Scotland and a normal risk elsewhere.

B: Forecast data:

1. Stratosphere:

Ozone values and deviation from average for the northern hemisphere are shown above as of 18th January 2023.

Temperature in the upper stratosphere over the N Pole at 19 and 30hPa is shown below. Some recovery from very low values at 10hPa are starting.

The stratosphere is in winter mode the N Pole at present but a major warming event is likely to occur later in January. The images below show the 10hPa height temperature anomaly analysis on the 19th January with selected forecast frames to 4th February. The stratospheric vortex is forecast to relocate and weaken as strong warming takes place. Despite the warming a westerly flow is maintained above UK and Europe in this forecast, A reversal of the flow takes place over USA and Canada and this may impact the surface weather evolution later in February and into March. It is too early to say if this will be the start of an early transition to “summer” mode for the stratospheric circulation.

2. Upper troposphere:

CFSv2 200hPa contours (top row) and CFSv2 anomaly (middle row) NMME anomaly (lower row) for and February, March and April 2023. The lower anomalies near the W of UK in February suggest a stronger Atlantic jet in February leading to an unsettled and possibly stormy period of weather for the UK. This risk markedly reduced for March and April in this forecast sequence.

3. Lower Troposphere:

A selection of model solutions for February to April 2023 using January data are shown below. The full set, including graphics for Spring 2023 can be found at https://www.weather-info.co.uk/wxsvc/seaslatest.html

Top row temperature anomaly and lower row precipitation anomaly

February to April 2023

CFSv2 E3 data

NMME

ECMWF

NASA

Data from WMO:

Three month average anomaly followed by Feb March April. Top row temperature anomaly and lower row precipitation anomaly.

WMO super ensemble (below) is a mean of data supplied by National Meteorological organisations across the globe. Because of the amount of data the output is a low resolution. (Exeter UKMO data missing from WMO server as of 20JAN2023)

Individual members of the WMO super ensemble are shown below.

BCC China (below)

BoM Australian (below)

CMCC (below)

CPTEC Brazil (below)

DWD Germany (below)

ECMWF (below)

CMA Canada (Below)

Moscow Russia (below):

Korea KMA (below):

Japan (below):

France (below):

UKMO Exeter – missing

USA Washington (below):

WMO super ensemble (below) for March April May: Indeterminate rainfall due to cancelling out of above and below forecasts from the various model output.

Graphics for Spring 2023 can be found at https://www.weather-info.co.uk/wxsvc/seaslatest.html

C: Comparing previous output:

October to December 2022 – based upon September 2022 data.

Full review data available here https://www.weather-info.co.uk/wxsvc/VerifOND2022.html

Original Summary – 200922 –

Above normal temperature is forecast for the season and each month although a limited number of models suggest December could have nearer normal values. Rainfall near normal for many areas but above in the N mainly NW and chance of below normal in the S/SW. Some suggestion that October could see well above normal rainfall and December less so and even below average. Pressure possibly above average.
Comment on the summary: Models continue to underestimate the occurrence of colder than average months. Overall forecast for above normal weas correct as was the suggestion that December cold be nearer average hinting at a colder month. Rainfall forecast of near average was OK for parts of England and Scotland but for most areas was under estimate of rainfall. Pressure forecast was poor.

Scoring will attempt to state Temperatures: good (if December was colder month), fair (above average for the 3 months), poor or no signal. Rainfall good for above average for season.
Revised order
1. Russia (combined): Temp fair . PPN good .
2. USA – CFS2 : Temp fair . PPN fair .
3. UKMO Contingency: Temp poor . PPN poor .
4. UKMO : Temp fair . PPN poor . PMSL poor
5. USA – IRI : Temp fair . PPN poor .
6. KMA APCC : Temp fair . PPN poor .
7. JMA : Temp good . PPN poor . PMSL poor
8. NMME : Temp fair . PPN good .
9. WMO multi : Temp fair . PPN poor .
10. BCC : Temp fair . PPN poor .
11. NASA : Temp fair . PPN poor .
12. CanSips : Temp good. PPN fair .
13. Copernicus Temp fair . PPN poor . PMSL poor
14. CMCC Temp fair . PPN poor . PMSL poor
15: DWD Temp fair. PPN poor . PMSL poor
16. EC Temp . PPN poor . PMSL poor
17 JMA Temp fair. PPN poor . PMSL poor
18 UKMO Temp fair . PPN poor . PMSL poor
19. MF Temp fair . PPN poor . PMSL poor
20 NCEP Temp fair . PPN poor . PMSL poor
21 ECCC Temp: fair. PPN poor . PMSL fair

WMO low res data:
BoM Temp fair . PPN poor .
Can Temp good . PPN fair .
DWD Temp fair . PPN poor .
KMA Temp GOOD . PPN poor .
MOSC Temp good . PPN poor .
WASH Temp fair . PPN poor .
CMA Temp fair . PPN poor .
ECMWF Temp fair . PPN poor .
UK Temp fair . PPN poor .
JMA Temp fair . PPN poor
MF Temp fair . PPN poor .
CMCC Temp good . PPN poor .
CPTEC Temp fair . PPN good .

D: Text Forecast for SW England

Remainder of Winter 2022/23 (February 2023).

After a cold start February is likely to be unsettled and milder than average although there is a chance of a colder end to the month.

Increased risk of gales.

Rainfall forecast (low confidence) is for above average rainfall, especially in western exposures and over the moors. Reduced snowfall compared to average although a small risk of snowfall remains for late in the month, mostly over hills.

Caution:
1: Due to large scale stratospheric warming out of the polar vortex there is increased uncertainty for the second half of February and for March. At present the indications are for a mostly mild and unsettled period which could lead to an early Spring.
2: Large scale blocking with cold easterly types seem to only be forecastable about two weeks ahead.

Winter Climate: 1981-2010 February average temperature values for lowland areas 6 or7°C in the West and 5 or 6°C in the East. Rainfall; February, lowland areas 80-100mm but 60-80mm in east. Around 200mm over moors. Snow climatology February possibly around 2 days on average with lying snow for low ground less than 5 days lying snow over lowland areas 5 to 10 hills, say hills around 200 metre elevation – one in three years have no lying snow.

Spring 2023 (March April May)

Overall milder than average temperature for the season. Chance of nearer normal in both March and May. Rainfall near normal. Slightly more indication of below average in April but a lot of inconsistency between models.

Summer 2023 (June July August) Limited data

Temperature likely to be slightly above average. Rainfall uncertain, near or above average overall but despite this number of rain days could be below average.

Autumn 2023 (September October November) very limited data.

Milder and wetter than average although just a hint some drier periods but this time suggestion is for October and / or November rather than September which was indicated in the December summary.

E: Caution.

F: References.

SST anomaly NOAA Remote Sens. 2014, 6(11), 11579-11606; doi:10.3390/rs61111579

IRI statistics: Mason, S.J. and L. Goddard, 2001: Probabilistic precipitation anomalies associated with ENSO. Bull. Amer. Meteor. Soc., 82, 619-638.

UK climate details see: http://www.metoffice.gov.uk/public/weather/climate/

NMME information: http://journals.ametsoc.org/doi/abs/10.1175/BAMS-D-12-00050.1

CFS2 info

‘Copernicus Products’ as listed in the C3S or CAMS Service Product Specification or any other items available through an ECMWF Copernicus http://climate.copernicus.eu

International seasonal monthly data from WMO

Climate data from The Met Office UK and NCEP USA

Contains public sector information licensed under the Open Government Licence v3.0.

Climate review and Experimental Long Range Forecast for SW England. December 2022.

Published 19 December 2022.

A: Overview

1. Influences.

Changes in sea temperature

Sea temperature anomalies in most of the Northern Hemisphere remain warmer than climatology for the middle of December. Baltic and Mediterranean temperatures remain well above normal. Pacific Ocean anomalies are similar in size to last month although the area of slightly colder than average temperature in the East Pacific near the North American coast has expanded slightly.

The Atlantic tropical storm season has ended. According to Wikipedia the tally for 2022 includes 16 depressions, 14 tropical storms, 8 Hurricanes 2 of which were major hurricanes (Cat3+). Estimated fatalities over 337 with total damage over 56 billion US dollars.

The Tropical Atlantic sea temperature anomalies remain slightly warmer than average and are forecast to move to near average through Spring 2023. (see Met Office graphic below).

Forecasts suggest that tropical Pacific Sea Surface Temperatures (nino3.4) are likely to trend towards El Nino conditions from late Spring 2023.

The North Atlantic Oscillation index (500hPa index shown below) has been neutral recently. The ensemble forecast is for a brief positive phase but then for negative conditions to develop although GFS operation model is not so convinced. Negative values imply WEAKER westerly winds across the Atlantic towards Europe although a neutral or weak signal is inconclusive.

See https://www.metoffice.gov.uk/weather/learn-about/weather/atmosphere/north-atlantic-oscillation

“The negative NAO phase represents the reverse with a weaker than usual difference in pressure.

Winds from the east and north-east are more frequent, bringing with them cold air, while the adjusted position of the jet stream leads to weaker and less frequent storms.

As a result, Europe and eastern US are more likely to experience cold, calm and dry winters. In contrast, northern Canada and Greenland will tend to be mild and wet.”

2. Recent Climatology

SW England: Up to the 18th of November, the temperature has been below average with negative anomalies of around 3 or 4 Celsius and frequent frost and even a little snow in places.. On the 18th and 19th temperatures rose to well above normal. Rainfall had been below average until the start of the wet spell on the 18th.

UK:

Met Office provisional Temperature and Rainfall anomalies for September, October and November 2022 are shown below: The higher rainfall in places during September and November has gone some way to recovering reservoir levels in Cornwall.

Copernicus, European temperature and rainfall anomalies for November 2022 and the year (Dec 2021 to Nov 2022) compared with 30 year period 1981-2010, are shown below..

UK River flows and ground water levels in October 2022 can be found in the November 2022 Hydrological Summary

Due to the very wet weather in November 2022 river levels recovered in many parts of the SW. The recent drier and colder spell in December has again reduced river flows as can be seen in the data for the 14th December (data from the nrfa.ceh.ac.uk UK water resource portal) shown below:

Reservoir levels, according to SW Water remain below the long term average across SW England as of 11th December 2022.

The Global Flood Awareness System – GloFAS – forecast from December 1st to end of May 2023 shows an elevated river flood risk in the S and E of England.

B: Forecast data:

1. Stratosphere:

Ozone values and anomalies as at 15th December (are shown above) for the N and S polar regions. The large Ozone hole over the Antarctic has largely reduced.

The stratosphere is in winter mode the N Pole. The images below show the 10hPa height temperature anomaly analysis on the 16th December with a forecast for 1st January 2023. The stratospheric vortex is forecast to intensify with a strengthening of the westerly flow at that level across the Atlantic and UK.

2. Upper troposphere:

CFSv2 200hPa contours (top row) and CFSv2 anomaly (lower row) for and January, February and March 2023. The lower anomalies near the NW of UK in January and possible stronger Atlantic jet in February, suggest an unsettled period of weather for the UK.

3. Lower Troposphere:

A selection of model solutions for January to March 2023 using December data are shown below. The full set, including graphics for Spring 2023 can be found at https://www.weather-info.co.uk/wxsvc/seaslatest.html

Top row temperature anomaly and lower row precipitation anomaly

January to March 2023

CFSv2

NMME

ECMWF

NASA

Data from WMO:

Three month average anomaly followed by Jan Feb and March. Top row temperature anomaly and lower row precipitation anomaly.

WMO super ensemble (below) is a mean of data supplied by National Meteorological organisations across the globe. Because of the amount of data the output is a low resolution.

Individual members of the WMO super ensemble are shown below.

BCC China (below):

BoM Australia (below):

CMCC (below):

CPTEC Brazil (below):

DWD Germany (below):

ECMWF EU (below)

Canada (below):

Moscow Russia (below):

Korea KMA (below):

Japan (below):

France (below):

UKMO Exeter (below):

USA Washington (below):

WMO super ensemble (below) for March April May:

Graphics for Spring 2023 can be found at https://www.weather-info.co.uk/wxsvc/seaslatest.html

C: Comparing previous output:

Autumn, September to November 2022 – based upon August 2022 data.

Full review data available here https://www.weather-info.co.uk/wxsvc/VerifSON2022.html

Original Summary – 160822 –

Temperature : Russia and Brazil output a little colder than the other models but only Russian data suggests (for the UK) near average with some areas below. The vast majority of model output suggests above average temperatures for the season and each month although probabilities are reduced across northern areas where there is a chance of nearer normal values. In addition there is a hint that anomalies may be lower in November but month to month details are not reliable.

Precipitation: For the season there is a fairly strong indication for normal or below average rainfall for the south of the UK and normal or above in the north. Strongest indication for wetter than average is in the NW, also more widely in October and perhaps for the east of the UK also in November.
Sea Level Pressure: above average pressure is indicated, highest probs in the south and west.

Comment on the summary: Temperature forecast was OK but rainfall and pressure were poor.

Scoring will attempt to state good, fair, poor or no signal.
Revised order
1. Russia (MHC,MGO): Temp good. PPN fair .
2. USA – CFS2 : Temp good. PPN poor .
3. UKMO Contingency: Temp good. PPN poor .
4. UKMO : Temp good. PPN poor . PMSL poor
5. USA – IRI : Temp poor. PPN poor .
6. KMA APCC : Temp good. PPN poor .
7. JMA : Temp good. PPN fair . PMSL poor
8. NMME : Temp good. PPN fair .
9. WMO multi : Temp good. PPN poor .
10. BCC : Temp good. PPN poor .
11. NASA : Temp good. PPN fair .
12. CanSips : Temp fair. PPN fair .
13. Copernicus Temp good. PPN poor . PMSL poor
14. CMCC Temp good. PPN poor . PMSL poor
15: DWD Temp good. PPN poor . PMSL poor
16. EC Temp good. PPN poor . PMSL poor
17 JMA Temp good. PPN poor . PMSL poor
18 UKMO Temp good. PPN poor . PMSL poor
19. MF Temp good. PPN poor . PMSL poor
20 NCEP Temp good. PPN poor . PMSL poor
21 ECCC Temp: good. PPN poor . PMSL poor

WMO low res data:
BoM Temp good. PPN fair .
Can Temp good PPN poor .
DWD Temp good. PPN poor.
KMA Temp good . PPN poor .
MOSC Temp poor . PPN fair .
WASH Temp good. PPN fair .
CMA Temp good. PPN poor .
ECMWF Temp good . PPN poor .
UK Temp good . PPN poor .
JMA Temp good . PPN poor
MF Temp good . PPN poor .
CMCC Temp good . PPN fair .
CPTEC Temp good . PPN fair .

D: Text Forecast for SW England

Remainder of Winter 2022/23 (January February 2023).

Temperature forecast for January is for near average but with a chance of another colder spell sandwiched between milder weather. It is possible that January could start colder than average. February is likely to be milder than average. Caution over recent years models have not picked out a colder spell more than about two or three weeks ahead.

Rainfall forecast (low confidence) is for near average precipitation in January with a chance of a drier and colder spell in between wetter periods.. February probably wetter in the N and W and drier in the S an E of the region. Snowfall likely to be below average, which means little if any snow for lower ground but some snow over the moors. Snow may be less likely in February.

January and February Climate: 1981-2010 average temperature values for lowland areas 7°C in the West and 5°C in the East similar for both months. Rainfall; January typically wetter than February. 1981-2010 January average 100-150 mm lowlands but over 200-300 mm over the Moors. February average 80-100mm for lowland areas, less in the east and a little more in the west. Moors over 150mm. Winter snow climatology less than 5 days lying snow over lowland areas 5 to 10 hills, say hills around 200 metre elevation – one in three years have no lying snow.

Spring 2023 (March April May)

Overall milder than average temperatures, though perhaps nearer normal May. Rainfall near normal, the chance of below normal being slightly higher than chance of above normal.

Summer 2023 (June July August) Limited data

Temperature likely to be above average. Rainfall uncertain, suggestion of below average in S and risk of above average in N and some western areas.

Autumn 2023 (September October November) very limited data.

Milder and wetter than average although just a hint that September could be drier.

E: Caution.

F: References.

SST anomaly NOAA Remote Sens. 2014, 6(11), 11579-11606; doi:10.3390/rs61111579

IRI statistics: Mason, S.J. and L. Goddard, 2001: Probabilistic precipitation anomalies associated with ENSO. Bull. Amer. Meteor. Soc., 82, 619-638.

UK climate details see: http://www.metoffice.gov.uk/public/weather/climate/

NMME information: http://journals.ametsoc.org/doi/abs/10.1175/BAMS-D-12-00050.1

CFS2 info

‘Copernicus Products’ as listed in the C3S or CAMS Service Product Specification or any other items available through an ECMWF Copernicus http://climate.copernicus.eu

International seasonal monthly data from WMO

Climate data from The Met Office UK and NCEP USA

Contains public sector information licensed under the Open Government Licence v3.0.

Climate review and Experimental Long Range Forecast for SW England. November 2022.

Published 19 November 2022.

A: Overview

1. Influences.

Changes in sea temperature

Sea temperature anomalies in most of the Northern Hemisphere are much warmer than climatology for the middle of November. Baltic and Mediterranean temperatures remain well above normal. Pacific Ocean anomalies are similar in size to last month although slightly colder than average in the East Pacific near the North American coast.

Wikipedia Atlantic tracks to 17th November 2022 are shown above. The tally for 2022 includes 16 depressions, 14 tropical storms, 8 Hurricanes 2 of which were major hurricanes (Cat3+). Estimated fatalities over 337 with total damage over 54 billion US dollars.

Timeline of storms shown below. (Wikipedia)

The Tropical Atlantic sea temperature anomalies remain slightly warmer than average and are forecast to remain slightly warmer through Spring 2023. (see Met Office graphic below).

Forecasts suggest that tropical Pacific Sea Surface Temperatures (nino3.4) are likely to trend towards El Nino conditions from late Spring 2023.

The North Atlantic Oscillation index (500hPa index shown below) has been uncertain/slightly positive recently. The ensemble forecast is for negative conditions to develop although GFS operation model is not so convinced. (CORRECTION) Negative values imply WEAKER westerly winds across the Atlantic towards Europe although a weak signal is inconclusive.

See https://www.metoffice.gov.uk/weather/learn-about/weather/atmosphere/north-atlantic-oscillation

“The negative NAO phase represents the reverse with a weaker than usual difference in pressure.

Winds from the east and north-east are more frequent, bringing with them cold air, while the adjusted position of the jet stream leads to weaker and less frequent storms.

As a result, Europe and eastern US are more likely to experience cold, calm and dry winters. In contrast, northern Canada and Greenland will tend to be mild and wet.”

2. Recent Climatology

SW England: Up to the 17th of November. The temperature has been above average with positive anomalies of between 2 and 4 Celsius, although some of this exaggerated by the typical fall in temperatures through November . Rainfall has been above average with many places already reaching or exceeding the November total and in places almost double the monthly total already.

UK:

Met Office provisional Temperature and Rainfall anomalies for August, September, October 2022 are shown below: The higher rainfall in places during September and October has not offset the “drought” with hosepipe bans still in effect across Cornwall and NW Devon from August 23rd.

Copernicus, European temperature and rainfall anomalies and soil moisture for October 2022 and the year (Nov2021 to Oct 2022) compared with 30 year period 1981-2010.

UK River flows and ground water levels in October 2022 can be found in the October 2022 Hydrological Summary

Due to the very wet weather in November 2022 river levels are now above average in many parts of the SW and in some areas are exceptionally high. (see image below for 16th November data from the nrfa.ceh.ac.uk UK water resource portal.)

Reservoir levels, according to SW Water, are well below the long term average across SW England as of 13th November 2022. Of the main reservoirs on Burrator was at almost full capacity.

The Global Flood Awareness System – GloFAS – forecast from November was not available on the 18th.

B: Forecast data:

1. Stratosphere:

Ozone values and anomalies as at 16th November (are shown above) for the N and S polar regions. A large Ozone hole is evident over the Antarctic.

The stratosphere is in winter mode the N Pole. The images below show the 10hPa height temperature anomaly analysis on the 18th November with a forecast for 22nd. The stratospheric vortex is not very stable and is forecast to split with a reduction in the westerly flow at that level across the Atlantic and UK. It is far too early to say if this will impact of the westerly jet stream and hence the winter temperatures.

2. Upper troposphere:

CFSv2 200hPa contours (top row) and CFSv2 anomaly (lower row) for December 2022 and January and February 2023. The lower anomalies near the W or NW of Uk in January and possible stronger Atlantic jet in February suggest an increasingly unsettled period for the UK.

3. Lower Troposphere:

A selection of model solutions for December 2022 to February 2023 using November data are shown below. The full set, including graphics for Sprig 2023 can be found at http://www.weather-info.co.uk/wxsvc/seaslatest.html

Top row temperature anomaly and lower row precipitation anomaly

December to February

CFSv2

NMME

ECMWF

NASA – (below)

Date from WMO:

Three month average anomaly followed by Dec Jan and Feb. Top row temperature anomaly and lower row precipitation anomaly.

WMO super ensemble (below)

BCC China (below)

BoM Australia (below)

CMCC (below)

CPTEC Brazil (below)

DWD Germany (below)

ECMWF EU (below)

Canada (below)

Moscow Russia (Below)

Korea KMA (Below)

Japan (Below)

France (Below)

UKMO Exeter (Below)

USA Washington (below)

C: Comparing previous output:

August to October 2022 – based upon July 2022 data.

Original Summary — 170722 –
Temperature: Strong signal for above average temperatures. Lower probs of occurance in the North where also lower anomalies. Anomalies in the south 1 C and in some models 1.5 C especilly in August. Several models indicate lower anomalies in October. Rainfall: Indication for drier than average conditions especially in the south. North probably near average for season but may start drier and end wetter. Some agreement for a wetter October more especially across the north and some western exposures with a minority suggesting this starts in September. Sea level pressure: more likely above normal in S..

Comment on the summary: Very good temperature indication. Fairly good rainfall and pressure indication.

Scoring will attempt to state good, fair, poor or no signal.
Revised order
1. Russia (WMO): Temp V Good got the less warm Sept in S . PPN good . (interesting difference with WMO data)
2. USA – CFS2 : Temp fair . PPN fair .
3. UKMO Contingency: Temp good . PPN poor .
4. UKMO : Temp good . PPN poor . PMSL fair
5. USA – IRI : Temp no signal . PPN no signal .
6. KMA APCC : Temp good . PPN no signal.
7. JMA : Temp good . PPN good . PMSL fair
8. NMME : Temp good . PPN good .
9. WMO multi : Temp good . PPN fair.
10. BCC : Temp fair . PPN fair .
11. NASA : Temp good . PPN poor .
12. CanSips : Temp good . PPN fair .
13. Copernicus Temp good . PPN good . PMSL fair
14. CMCC Temp good . PPN fair . PMSL poor
15: DWD Temp good . PPN good . PMSL good
16. EC Temp good . PPN poor . PMSL good
17 JMA Temp good . PPN poor PMSL poor
18 UKMO Temp good . PPN poor . PMSL fair
19. MF Temp good . PPN good . PMSL good
20 NCEP Temp good . PPN fair. PMSL fair
21 ECCC Temp: good . PPN poor. PMSL poor

WMO low res data:
BoM Temp good . PPN fair .
Can Temp good . PPN fair
DWD Temp good . PPN fair.
KMA Temp good . PPN fair .
MOSC Temp poor. PPN fair .
WASH Temp good. PPN fair .
CMA Temp good . PPN fair
ECMWF Temp good . PPN good .
UK Temp good . PPN poor .
JMA Temp good . PPN poor
MF Temp good . PPN fair.
CMCC Temp good. PPN poor .
CPTEC Temp good. PPN fair .

Verification details can be found here: http://www.weather-info.co.uk/wxsvc/Verification.html

D: Text Forecast for SW England

Winter 2022/23 (December January February).

Temperature forecasts continue to suggest a milder than average winter. Each month may well be above average but December may be closer to average and there is a chance of a colder spell during the month. A caution is that over recent years models have not picked out a colder spell more than about two or three weeks ahead.

Rainfall forecast is for near average or below average for the season. Near average may be a result of averaging out between the wetter and drier model solutions. December possibly near or below average other months not clear cut. Snowfall likely to be below average, which means little if any snow for lower ground but some snow over the moors. Snow may be less likely in February and slightly more likely in December than average (again most likely over the moors).

Spring 2023 (March April May)

Overall milder than average temperatures, perhaps nearer normal May. Near or above average rainfall,

Summer 2023 (June July August) Limited data

Above normal temperatures indicated with below average rain early in the summer but above average later.

E. Caution.

F: References.

SST anomaly NOAA Remote Sens. 2014, 6(11), 11579-11606; doi:10.3390/rs61111579

IRI statistics: Mason, S.J. and L. Goddard, 2001: Probabilistic precipitation anomalies associated with ENSO. Bull. Amer. Meteor. Soc., 82, 619-638.

UK climate details see: http://www.metoffice.gov.uk/public/weather/climate/

NMME information: http://journals.ametsoc.org/doi/abs/10.1175/BAMS-D-12-00050.1

CFS2 info

‘Copernicus Products’ as listed in the C3S or CAMS Service Product Specification or any other items available through an ECMWF Copernicus http://climate.copernicus.eu

International seasonal monthly data from WMO

Stratospheric Diagnostics from Japan Met Agency and ECMWF via Free University Berlin

Climate data from The Met Office UK and NCEP USA

Contains public sector information licensed under the Open Government Licence v3.0.

Climate review and Experimental Long Range Forecast for SW England. October 2022.

Published 19 October 2022.

A: Overview

1. Influences.

Changes in sea temperature

Sea temperature anomalies in most of the Northern Hemisphere are much warmer than climatology for the middle of October apart from a colder anomaly just to the North of Scotland. Baltic and Mediterranean temperatures remain well above normal. Pacific Ocean anomalies are similar in size to last month.

Wikipedia Atlantic tracks to 15th October 2022

Wikipedia details the 2022 Atlantic hurricane season to 16 October as follows. Since the first system on 5th June there have been 13 tropical depressions, 11 tropical storms, 5 hurricanes two of which were CAT3 or above. There have been at least 296 deaths and damages estimates amount to over 53 billion US dollars. (Wikipedia).

Timeline for the Atlantic Hurricane season 2022

The Tropical Atlantic sea temperature anomalies remain warmer than average and are forecast to remain slightly warmer through to Sprin 2023. (see Met Office graphic below).

Forecasts suggest that tropical Pacific Sea Surface Temperatures (nino3.4) are likely to have similar anomalies through the autumn with weak La Nina conditions forecast to persist. A trend to Neutral conditions is possible during the winter 2022/23 and perhaps turning to El Nino conditions for Spring 2023.

The North Atlantic Oscillation index (500hPa index shown below) has been uncertain/neutral for a week or two before turning negative on 13th October. The forecast is for a return to near neutral conditions over the next two weeks. Negative values imply stronger westerly winds across the Atlantic towards Europe although a weak signal is inconclusive.

2. Recent Climatology

SW England: Up to the 19th of October. Temperature was above average for the month with anomalies of 1.5 to 2 degrees Celsius. Rainfall was below average across SW England although local thunderstorms make totals rather variable. Sunshine was a little above average to date..

UK:

Met Office provisional Temperature and Rainfall anomalies for July, August, September 2022 are shown below: Rainfall in July was a record low across southern and SE England and in some central and southern parts of the UK record high temperatures also occurred. The higher rainfall in places during September has not offset the “drought” with hosepipe bans still in effect across Cornwall and NW Devon from August 23rd.

Copernicus, European temperature and rainfall anomalies and soil moisture for September 2022 and the year (Oct 2021 to Sept 2022) compared with 30 year period 1981-2010.

UK River flows and ground water levels in September 2022 reflected the very dry weather and were well below average. Details can be found in the September 2022 Hydrological Summary

From the nrfa.ceh.ac.uk UK water resource portal. River flow data as of 17th October 2022 (shown below) shows limited recovery from the exceptionally low flows in September.

Reservoir levels, according to SW Water, are well below the long term average across SW England as of 16th October 2022.

Global Flood Awareness System – GloFAS – flood risk for October to January suggests that the river flood risk is average or below average across the England and Wales due to low ground water values. This does not include “flash” floods caused for example by localised heavy rain which with dry soils can lead to increased run off.

B: Forecast data:

1. Stratosphere:

Top 10hpa 19th October N pole and S Pole. Below stratospheric Ozone deviations from average.

The stratosphere is in winter mode the N Pole. In the South there is a strong stratospheric vortex and marked ozone hole. The graphs below show the t0hPa temperature tracks and Ozone hole details for the S Polar region (left) and for comparison the N Polar region.

Global Ozone average total atmosphere in DU for the 1st of each month.

2. Upper troposphere:

CFSv2 200hPa contours (top row) and CFSv2 anomaly (lower row) for November, December 2022 and January and February 2023. The higher than average heights forecast could be due to higher than average temperatures in depth through the atmosphere? Note the lower anomalies near the NW of Uk in January and possible stronger Atlantic jet in February due to increased thermal contrast.

3. Lower Troposphere:

A limited selection of model solutions for November 2022 to January 2023 using October data are shown below followed by winter period December 2022 to February 2023. The full set can be found at http://www.weather-info.co.uk/wxsvc/seaslatest.html

Top row temperature anomaly and lower row precipitation anomaly

November to January

Winter – December to February

Date from WMO: Three month average anomaly followed by Dec Jan and Feb. Top row temperature anomaly and lower row precipitation anomaly.

C: Comparing previous output:

July to September 2022 – based upon June 2022 data.

Original Summary — 180622 –
Temperature: Above average temperature most likely although July may be near normal with larger anomalies in August and possibly September Rainfall: More models have below average rainfall than above at least for the south. In the north more likely to be normal with a stronger signal for above normal rainfall. Hint at September being the most likely wetter than average month.

Comment: Above average temperature was correct and the hint at larger anomalies in August was correct for southern half of UK although not September. Rainfall, good indication for below average rainfall and the wetter September.

Scoring will attempt to state good, fair, poor or no signal.
Revised order
1. Russia (WMO): Temp good . PPN good .
2. USA – CFS2 : Temp fair . PPN fair .
3. UKMO Contingency: Temp good . PPN poor .
4. UKMO : Temp good . PPN fair . PMSL fair
5. USA – IRI : Temp good . PPN poor .
6. KMA APCC : Temp good . PPN poor .
7. JMA : Temp good . PPN good . PMSL poor
8. NMME : Temp good . PPN good
9. WMO multi : Temp good . PPN poor .
10. BCC : Temp good . PPN fair .
11. NASA : Temp good . PPN poor .
12. CanSips : Temp good . PPN fair .
13. Copernicus Temp good . PPN fair . PMSL fair
14. CMCC Temp good . PPN poor. PMSL poor.
15: DWD Temp good . PPN poor. . PMSL poor.
16. EC Temp good . PPN poor . PMSL poor
17 JMA Temp good. PPN good . PMSL poor
18 UKMO Temp good . PPN poor . PMSL poor
19. MF Temp good . PPN good . PMSL fair
20 NCEP Temp good . PPN fair . PMSL fair
21 ECCC Temp: good. PPN fair . PMSL poor

WMO low res data: 3 month mean.
BoM Temp good. PPN good/fair .
Can Temp good. PPN good/fair .
DWD Temp good. PPN good/fair .
KMA Temp good PPN poor .
MOSC Temp fair . PPN fair .
WASH Temp good. PPN good/fair .
CMA Temp good . PPN poor .
ECMWF Temp good . PPN poor .
UK Temp good . PPN fair .
JMA Temp good. PPN good/fair
MF Temp good. PPN good/fair .
CMCC Temp good . PPN poor
CPTEC Temp good . PPN good .

D: Text Forecast for SW England

Remainder of Autumn 2022 (November).

Strong indication for above normal temperature values.

Rainfall in November near or below average. Slightly more solutions favor below average rainfall than above average.

Autumn climate: 1981 to 2010 average mean temperature 11 or 12°C but nearer 10°C in rural areas. Maximum temperatures average 14 to 16°C. November average around 9 or 10 Celsius. Average 1981 to 2010 rain 300 to 400mm, 600 to 800mm over the moors but east of the moors and in lowland Somerset more like 200 to 300mm. November totals range from around 80mm east of the moors to over 200mm over the moors.

Winter 2022/23 (December January February).

Temperature forecasts continue to suggest a milder than average winter although December may be close to average and February well above.

Rainfall forecast is for near average or below average for the season. Near average may be a result of averaging out between the wetter and drier model solutions. December possibly near average, chance of below in January but above average in February. Snowfall likely to be below average, which means little if any snow for lower ground but some snow over the moors. Snow may be less likely in February and slightly more likely n December than average. (again most likely over the moors)

Spring (2023 March April May) Limited data

Overall milder than average temperatures, perhaps nearer normal April. Near or above average rainfall although possible drier than average in March and wetter than average in May.

E. Caution.

Experimental Long Range Forecasts do not have a good success rate. especially with regards to precipitation. The models are good at predicting above average values but not for picking a one off colder month. The data used for the above forecast summary can be seen at here.

F: References.

SST anomaly NOAA Remote Sens. 2014, 6(11), 11579-11606; doi:10.3390/rs61111579

IRI statistics: Mason, S.J. and L. Goddard, 2001: Probabilistic precipitation anomalies associated with ENSO. Bull. Amer. Meteor. Soc., 82, 619-638.

UK climate details see: http://www.metoffice.gov.uk/public/weather/climate/

NMME information: http://journals.ametsoc.org/doi/abs/10.1175/BAMS-D-12-00050.1

CFS2 info

‘Copernicus Products’ as listed in the C3S or CAMS Service Product Specification or any other items available through an ECMWF Copernicus http://climate.copernicus.eu

International seasonal monthly data from WMO

Stratospheric Diagnostics from Japan Met Agency and ECMWF via Free University Berlin

Climate data from The Met Office UK and NCEP USA

Contains public sector information licensed under the Open Government Licence v3.0.

Climate review and Experimental Long Range Forecast for SW England. September 2022.

Published 20 September 2022.

A: Overview

1. Influences.

Changes in sea temperature

Sea temperature anomalies in most of the Northern Hemisphere are much warmer than climatology for the middle of September. The area of colder than average temperatures southwest of Portugal have warmed out which may account for the recent increase in Atlantic tropical cyclone activity, although this is normally a time when increased activity is present. Mediterranean temperatures have been high enough for tropical storm type formation. Pacific Ocean anomalies are similar to last month.

Wikipedia Atlantic tracks to 15th September 2022 does not show Fiona

The Tropical Atlantic sea temperature anomalies remain warmer than average and are forecast to remain slightly warmer through most of the winter. (see Met Office graphic below). (NOTE last month Indian Ocean graphic was used in error)

Forecasts suggest that tropical Pacific Sea Surface Temperatures (nino3.4) are likely to have similar anomalies through the autumn with weak La Nina conditions forecast to persist. A trend to Neutral conditions is possible later in the winter 2022/23 and perhaps an El Nino for Spring 2023, although there is not a great deal of support for the CFS forecast.

The North Atlantic Oscillation index (500hPa index shown below) has been uncertain/slightly positive recently. The ensemble forecast is for negative conditions to develop although GFS operation model is not so convinced. (CORRECTION) Negative values imply WEAKER westerly winds across the Atlantic towards Europe although a weak signal is inconclusive.

Seehttps://www.metoffice.gov.uk/weather/learn-about/weather/atmosphere/north-atlantic-oscillation

“The negative NAO phase represents the reverse with a weaker than usual difference in pressure.

Winds from the east and north-east are more frequent, bringing with them cold air, while the adjusted position of the jet stream leads to weaker and less frequent storms.

As a result, Europe and eastern US are more likely to experience cold, calm and dry winters. In contrast, northern Canada and Greenland will tend to be mild and wet.”

2. Recent Climatology

SW England: Up to the 15th of September. Temperature was above average for the month with anomalies of 2 or 3ven 3 degrees Celsius. Rainfall was average or above average across SW England but sunshine was about half of what might be expected so far in September.

UK:

Met Office provisional Temperature and Rainfall anomalies for June, July, August 2022 are shown below: Rainfall in July was a record low across southern and SE England and in some central and southern parts of the UK record high temperatures also occurred.

June rainfall shown as near average was in fact slightly below average across most of Devon and slightly above in south Cornwall and parts of N and E Somerset.

Copernicus, European temperature and rainfall anomalies and soil moisture for August 2022 and the Summer (June to August 2022) compared with 30 year period 1981-2010.

UK River flows and ground water levels in August 2022 reflected the very dry weather and were well below average. Details can be found in the August 2022 Hydrological Summary

From the nrfa.ceh.ac.uk UK water resource portal. River flow data as of 18th September 2022 (shown below) shows some recovery from the exceptionally low flows in August.

Global Flood Awareness System – GloFAS – flood risk for September to December suggests that the river flood risk is average or below average across the UK, due to low ground water values. This does not include “flash” floods caused for example by localised heavy rain which with dry soils can lead to increased run off.

Reservoir levels, according to SW Water, are below the long term average across SW England as of 4th September 2022 (not sure why this has not been updated). The Environment Agency previously confirmed drought status in 14 areas of the UK including: Devon and Cornwall.

B: Forecast data:

1. Stratosphere:

The stratosphere remains in “summer” mode across the N Pole. In the South there is a strong stratospheric vortex and marked ozone hole.

2. Upper troposphere:

CFSv2 200hPa contours (top row) and CFSv2 anomaly (lower row) for October November December 2022. The higher than average heights forecast could be due to higher than average temperatures in depth through the atmosphere?

3. Lower Troposphere:

Selection of model solutions for October to December 2022 using September data are shown below.

Other graphics can be viewed at http://www.weather-info.co.uk/wxsvc/seaslatest.html

Top row temperature anomaly and lower row precipitation anomaly

ource Data WMO low resolution super ensemble for August to October 2022 based on July data. Full data at http://www.weather-info.co.uk/wxsvc/seaslatest.html

Top row temperature anomaly and lower row precipitation anomaly. Left image three month mean then individual months.

Available Graphics for Winter (December 2022 / January and February 2023) can be seen at http://www.weather-info.co.uk/wxsvc/seaslatest.html Previous issues are available by following link on the web page.

C: Comparing previous output:

June to August 2022 – based upon May 2022 data.

Original Summary -Summary – 170522 –
Temperature: all models suggest “summer” will have above average temperatures. A few models suggest either June or July could be near average. Typical values suggested 0.5 to 1C above average locally 1 to 2C in south and 0.2 to 0.5C in the north.
Rainfall: Main theme seems to be increased chance of below average rainfall in the south and above average in the N or NW of Scotland. Elsewhere near normal although August might be see above average rainfall in the south after a drier July.
Pressure: near normal perhaps below in the north early on and below in the south later in the season.

Comment: Temperature forecast good anomalies over 2 C in parts of S and E. Rainfall good indication including idea of July being drier than August in parts of the south. Pressure indication poor.

Scoring will attempt to state good, fair, poor or no signal.
Revised order
1. Russia (WMO): Temp fair . PPN poor .
2. USA – CFS2 : Temp good . PPN poor .
3. UKMO Contingency: Temp fair . PPN poor .
4. UKMO : Temp good . PPN poor . PMSL poor
5. USA – IRI : Temp fair . PPN poor .
6. KMA APCC : Temp good . PPN no signal – fair in S .
7. JMA : Temp good . PPN good . PMSL poor
8. NMME : Temp good . PPN poor .
9. WMO multi : Temp good . PPN fair .
10. BCC : Temp good . PPN good .
11. NASA : Temp good . PPN poor .
12. CanSips : Temp good . PPN almost good .
13. Copernicus Temp good . PPN fair . PMSL poor
14. CMCC Temp good . PPN poor . PMSL poor
15: DWD Temp good . PPN poor almost fair . PMSL poor
16. EC Temp good . PPN fair . PMSL poor
17 JMA Temp good . PPN fair . PMSL poor
18 UKMO Temp good . PPN fair . PMSL poor
19. MF Temp good . PPN fair . PMSL fair
20 NCEP Temp good . PPN poor . PMSL poor
21 ECCC Temp: good. PPN fair . PMSL poor
22 ECMWF monthly Temp: good. PPN fair almost good .

WMO low res data: 3 month average
BoM Temp good. PPN poor.
Can Temp good. PPN good.
DWD Temp good. PPN fair.
KMA Temp good. PPN fair.
MOSC Temp good. PPN poor.
WASH Temp good. PPN poor.
CMA Temp good. PPN fair.
ECMWF Temp good. PPN fair.
UK Temp good. PPN poor.
JMA Temp good. PPN good
MF Temp good. PPN almost good.
CMCC Temp good. PPN fair.
CPTEC Temp good. PPN good .

D: Text Forecast for SW England

Remainder of Autumn 2022 (October November).

Strong indication for above normal temperature values for both months.

Rainfall, October probably well above normal with near normal values likely in November.

Autumn climate: 1981 to 2010 average mean temperature 11 or 12°C but nearer 10°C in rural areas. Maximum temperatures average 14 to 16°C. November normally colder than October. Average 1981 to 2010 rain 300 to 400mm, 600 to 800mm over the moors but east of the moors and in lowland Somerset more like 200 to 300mm.

Winter 2022/23 (December January February). Very limited data.

Temperature forecasts continue to suggest a milder than average winter although December may only be slightly above.

Rainfall forecast is for near average for the season although some western exposures may have above average values. January could be wetter than average. Some models suggest much wetter than normal but these are balanced by the drier than average solutions. Snowfall likely to be below average, which means little if any snow for lower ground but some snow over the moors.

Spring (2023 March April May)

Overall milder than average temperatures and near or above average rainfall

E. Caution.

Experimental Long Range Forecasts do not have a good success rate. The data used for the above forecast summary can be seen at here.

F: References.

SST anomaly NOAA Remote Sens. 2014, 6(11), 11579-11606; doi:10.3390/rs61111579

IRI statistics: Mason, S.J. and L. Goddard, 2001: Probabilistic precipitation anomalies associated with ENSO. Bull. Amer. Meteor. Soc., 82, 619-638.

UK climate details see: http://www.metoffice.gov.uk/public/weather/climate/

NMME information: http://journals.ametsoc.org/doi/abs/10.1175/BAMS-D-12-00050.1

CFS2 info

‘Copernicus Products’ as listed in the C3S or CAMS Service Product Specification or any other items available through an ECMWF Copernicus http://climate.copernicus.eu

International seasonal monthly data from WMO

Stratospheric Diagnostics from Japan Met Agency and ECMWF via Free University Berlin

Climate data from The Met Office UK and NCEP USA

Contains public sector information licensed under the Open Government Licence v3.0.

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