December and the first of the three meteorological winter months has been mild for Ireland, UK and much of Europe.

Europe temp anomaly through 24th December.

One of the warmest December’s over the higher lats of Eurasia, North America but also note the chill across N Africa, Middle East and mid lat Asia.

The rest of the month shall be on the whole, mild across particularly N Europe including UK, Ireland.

At times it’s been stormy with Storm Darragh causing significant impacts on 6-7th December with greatest impacts across England, Wales and Ireland while it turned very wet and windy for more northern areas of the UK 14-15th December with winds gusting 109 mph over Cairngorm, 83 mph South Uist and 77 mph Stornoway.

Cold spells have been somewhat brief and relatively tame by early winter standards.

The year will likely be one of the warmest of record both for Europe as well as globally.

One of the few places on earth where 2024 will be colder than normal is Iceland.

December 2024 Monthly Weather Report

Met Office UK December Extremes

Highest Maximum 15.9°C on 1st at Westonzoyland (Somerset, 3mAMSL)
Lowest Maximum -4.3°C on 10th at Balmoral (Aberdeenshire, 283mAMSL)
Highest Minimum 13.2°C on 1st at Bude (Cornwall, 15mAMSL)
Lowest Minimum -11.2°C on 11th at Tyndrum No 3 (Perthshire (in Central Region), 168mAMSL)
Lowest Grass
Minimum -14.3°C on 11th at Tyndrum No 3 (Perthshire (in Central Region), 168mAMSL)
Most Rainfall 144.2mm on 31st at Honister Pass (Cumbria, 358mAMSL)
Most Sunshine 6.9hr on 8th at Exeter Airport No 2 (Devon, 27mAMSL)
Highest Gust 83Kt 96mph on 7th at Berry Head (Devon, 58mAMSL)
Highest Gust
(mountain*)
95Kt 109mph on 15th at Cairngorm Summit (Inverness-shire, 1237mAMSL)
also on 21st at Cairngorm Summit (Inverness-shire, 1237mAMSL)
Greatest Snow
Depth at 0900
UTC
5cm on 31st at Strathy East (Sutherland, 68mAMSL) and Orkney: Loch Of
Hundland (Orkney, 28mAMSL)

My December Stats

My December Highlights

Much WETTER than Nov (only 39.07mm) & much MILDER than last Dec (3.9°C in 2023 v 5.3°C in 2024)

Very mild opening day (14.9°C) & Xmas Eve (14.0°C)

Fewer nights below 0°C (8) to Nov (10) & last Dec’s 15 nights.

Min Temp -4.2 in 2024 vs -9 in 2023

UK, Ireland & Europe Highlights

10th Dec: According to Thierry Goose, -49.5°C Sukhana, lowest temperature of the season in #Russia. Meanwhile, the two coldest inhabited places in the world, Verkhoyansk & Oymyakon, are experiencing one of the warmest first thirds of December since records began. In Oymyakon, the anomaly is +15.5°C. Crazy!

16th Dec: According to Extreme Temperatures Around The World, 31 AT NIGHT IN THE CANARY ISLANDS and… OVERNIGHT MINUMUM 29.6 Puerto de La Cruz is HOTTEST DECEMBER NIGHT EVER RECORDED IN THE WHOLE NORTHERN HEMISPHERE (it beats Bangkok)

18th Dec: According to Torsten Hanssen, The difference between the lowest and highest temperature in Norway Wednesday 18th December was 51.5C!! Cuovddatmohkki in northern Norway observed the lowest temperature so far in Norway this winter with -38.1C Wednesday night the temperature in Tafjord climbed to +13.4C.

23rd Dec: Heavy #snow in the Swiss Alps, up to 244 cm at Tsanfleuron [2,569 m] on the last 7 days. New snow in 24 h [stations > 2,000 m]: 119 cm Tsanfleuron 114 cm Grand Cor 92 cm Gandegg & Alpler Tor 90 cm Étang de Trente Pas 88 cm Ortstock Matt 85 cm Bortelsee … 39 cm Crans-Montana

24th Dec: It was the warmest Christmas Eve on record for Northern Ireland with 14.3C reached at Magilligan, Co Londonderry. This surpasses the previous NI Christmas Eve record of 13.9C set at Armagh back in 1942.

25th Dec: It was the mildest start to Christmas on record for Scotland. A low of 12.1 at Kinloss, Moray surpasses the previous Scottish record of 10.6C set at Dounreay on the North Coast back in 1971.

30th Dec: Cold night in the Swiss and French mountains, especially in sinkholes and mid-altitude sites. -26.8°C Darbounouse -25.6°C Combe d’Amburnex -25.0°C Sägistalsee -24.0°C La Brévine [Tx -11.9°C] -22.8°C Combe de l’Oscence -22.4°C Brizon – Doline de Solaison -22.3°C Combe de Reculfoz.

2024 Stats

Germany like much of Central Europe witnessed it’s warmest year on record in 2024.

The Paris-Montsouris site received 901mm of rain during 2024 which makes it the wettest year for the central Paris site since records began back in 1873. 3 out of the top 4 wettest years have occurred since 2000.

MJO Remains A Good Indicator For Warm & Cold Episodes into January…

Part of the cause for the milder than average and at times, stormy December is ‘in-part’ down to the rotation through the warm and somewhat stormy MJO phases of 2-3 and 4-5 coinciding with a strengthening of the polar vortex.

The below 90-day phase plot graphic shows this rotation commencing back around 20th November with full effects only kicking in during the close of the month into December.

The last rotation through the cold phases of 7-8 happened late October into early November with atmosphere roughly 10-14 days after.

The MJO and AO/NAO have both very nicely reflected each other through autumn as seen in the below graphic.

PROLONGED COLD SPELL IN JANUARY?

We are likely to see the return of phase 7 in the coming 10-15 days as can be seen in the below GFS ensemble phase diagram.

ECMWF also on board with amplitude into phase 7.

Both NAO and particularly AO are trending negative.

The models see the building of heights into the arctic following the initial low height field over Arctic/Greenland which mirrors nicely with the 50mb level above.

The two above height fields (50mb down to 500mb) essentially reinforce WHY the pattern is becoming SO MILD through the mid lats for Christmas.

The polar vortex has been somewhat decoupled through much of December with an ever strengthening ‘stratospheric PV’ but weaker ‘tropospheric PV’ hence the cross polar flow and arctic intrusions into North America but in the below vertical cross section, this shows increasingly cold upper levels propogating downwards into lower strat and this is forcing the tightening of the tropospheric circulation which drives an increasingly mild Europe, N America and Asia Christmas to New Year as seen above.

Record strong mean zonal winds at 10mb at 60N.

Note the cold transferring from 10mb downwards.

GFS ensemble polar cap height projection.

Change is likely, but WHEN?

With the aid of tropical forcing, high latitude blocking is set to re-establish itself over the higher latitudes and this ‘should’ drive upward heat flux, kicking off wave breaks from trop into strat which decelerates the mean zonal wind through the stratosphere.

Note the flip in the height field from negative back to positive.

Another aspect to consider is HOW COLD, if we get the right ridge-trough setup here in NW Europe. In other words the block W of Ireland extending up through Greenland which cuts off the Atlantic and holds more N or NE flow.

The build-up of cold within the arctic courtesy of a strong PV could mean ‘stronger cold’ released south. How strong and how long? Certainly the GFS ensemble holds the blocking within the arctic and Greenland most of January which would provide a lengthy drag on the strat circulation which the ECM suggests when looking again at the mean zonal wind. Could this lead to an SSW?

I suspect a lot depends upon how strong the MJO get’s in phase 7 and where it goes after. A collapse in 7 could support a longer lived cold, blocky setup but I shall lean towards milder perhaps from 20th onwards. Some fluctuation between cold and something milder is possible even within the overall cold pattern.

The GFS ensemble carries the cold signal pretty much all the way till the end of January.

7-day temp anomalies

Day 1-7

7-14

14-21

21-28

28-35

Here’s the upcoming 35 day temp anomaly for Europe.

My January Verdict

Average to Slightly Colder & Drier Than Average January for W/NW Europe Including UK & Ireland, Warmer than Average Eastern Europe.

Tags: featured, monthly-outlook