December follows October and November as being a very wet month. It started cold and dry then turned very mild but also very wet. Christmas to New Year has seen it turn somewhat colder and snowier, especially in the north.
The month overall coincides quite well with my December Outlook (scoring 8 out of 10)
First week of December 2023
1-28th December 2023
A look back at December 2023
Howard Davis Farm recorded a total of 328.7mm of rain in November 2023. This is provisionally the highest amount of rain reported at any of our observing sites in Jersey, for any month across all the years that we've been observing the weather. pic.twitter.com/9J2WeXZi7E
— Jersey Met (@Jersey_Met) December 1, 2023
HISTORIC WARM SPELL IN EUROPE
Bosnia and Herzegovina 23.5C Zenica NEW NATIONAL RECORD HIGH FOR DECEMBERSeveral other records were beaten in Italy,Albania,Serbia,Croatia,France (Corsica).
See list of the most important below:
[also 19.4C Sibiu ROMANIA not on the list] pic.twitter.com/d76Fmbw7K4— Extreme Temperatures Around The World (@extremetemps) December 1, 2023
????️-17.0°C in Isenvad, #Denmark ????????! ????
It's the coldest temperature this early in the winter in the country since 1985.
It's also the 4th Tmin < -10°C in a row in the country, which is unseen this early since 1973. https://t.co/Bc92eyB5EM pic.twitter.com/mqvz2Ov8Pr— Thierry Goose (@ThierryGooseBC) December 2, 2023
❄️ Close to 50 cm of #snow in some parts of #Munich ????????, the greatest snowfall in 20 years in the Bavarian capital! #München @extremetemps @ScottDuncanWX @MAnderson003 https://t.co/PKkPNybff6
— Thierry Goose (@ThierryGooseBC) December 2, 2023
????️Nombreux records mensuels de Tmax dans les Balkans ce 2-12-2023
En #Serbie, 25.6°C à Valjevo, à 0.4° du record national de 1989. 22.7°C à #Belgrade, nouveau record pour la capitale (et 22.9 à l'aéroport)
En #Croatie, 23.5°C à Slavonski Brod, à 0.2° du record national de 1989.???? https://t.co/efCHRmmOgH pic.twitter.com/CCocttkdlf— Etienne Kapikian (@EKMeteo) December 2, 2023
In #Austria ????????, there is #snow on the ground in all state capitals, which is quite rare in early December.#Vienna is experiencing its greatest snow depth (21 cm) since February 2013. #schnee @GeoSphere_AT @severeweatherEU @GaetanHeymes @Francois_Jobard @TheSnowDreamer https://t.co/8oFnbX8xIg
— Thierry Goose (@ThierryGooseBC) December 3, 2023
???? Very cold temperatures this morning in #Switzerland ???????? (high elevations + frost hollows).
Note a frigid diurnal *Tmax* just above -32°C at Sägistalsee! Source: https://t.co/5Kek4StowR
Tomorrow morning could be even colder. pic.twitter.com/xx4TjQeQnZ
— Thierry Goose (@ThierryGooseBC) December 3, 2023
Brutal cold night in the Alpine area.
The airport of Munich in GERMANY dropped to -18.1C this morning,extremely low for early December.
This week will remain frigid, than milder conditions might be on the way.
Spain will enjoy temperatures up to 25C+ and Morocco even 30C. pic.twitter.com/2az70CsVde— Extreme Temperatures Around The World (@extremetemps) December 4, 2023
???? #Siberia ???????? strikes again this morning with -58.7°C in Iema, its coldest temperature in December in more than 40 years.
This is the 3rd year in a row that Siberia has extreme #cold in early December (-61.1°C Delyankir, Dec. 8, 2021; -61.0°C Oymyakon, Dec. 12, 2022). #Russia pic.twitter.com/mbYsD7AuWQ— Thierry Goose (@ThierryGooseBC) December 5, 2023
Currently 22C in parts of Spain, 12C SW England while it's -44.2C at Kazym River, Russia. pic.twitter.com/YCfHNMQ2Ie
— MarkVoganWeather.com (@MarkVogan) December 10, 2023
Exceptional heat in #Spain ???????? with up to 29.7°C in Partaloa, north of #Almeria!
If reliable, this would [unofficially] be the highest temperature ever recorded in Spain in December!Also 27.7°C in #Valencia Airport and 27.3°C in Valencia Observatory, both are monthly records. https://t.co/UCVnkkl2ZP pic.twitter.com/jTaWrlOXas
— Thierry Goose (@ThierryGooseBC) December 11, 2023
New December national record broken in #Spain ???????? with 29.9°C in Malaga! ????
Amateur stations recorded up to 31.2°C in Arboleas (Almeria), unofficially the highest temperature ever recorded in Europe in December! Crazy. @ScottDuncanWX https://t.co/raRX5ScFqf— Thierry Goose (@ThierryGooseBC) December 12, 2023
The flood situation continues in France. https://t.co/egBOwa8524
— MarkVoganWeather.com (@MarkVogan) December 14, 2023
Cold has been remarkable in northern Europe since October. Interestingly, Oct-Dec cold in Finland is much more common during La Niña, but 2002 (exceptionally cold) was an El Niño winter.
Highlights for rest of winter 02/03 were the SSW on Jan 18, and the US East Coast blizzard. https://t.co/HsTvUrI526 pic.twitter.com/FUaaGLe8Ap
— World Climate Service (@WorldClimateSvc) December 14, 2023
The wettest place in Finland this year, Nurmes Mujejärvi, has recently passed the 1000 mm annual precipitation threshold.
The station is currently the only one in Finland with four-digit annual precipitation. The last time 1000 mm was exceeded was in 2020. pic.twitter.com/GxmphTjaBu
— Mika Rantanen (@mikarantane) December 14, 2023
Helsinki has been now below zero (0°C) for an impressive 21 consecutive days, i.e. since 25 November.
This long frosty spell will be broken tomorrow.
Such a long period of frost this early in the winter is very unusual ???? pic.twitter.com/sBdeiRD4LE
— Mika Rantanen (@mikarantane) December 15, 2023
The October-November combined was the second coldest such period in Finland in this century. Only Oct-Nov 2002 was colder.
In the last century, however, such cold spells were much more common. pic.twitter.com/v6106BrSDG
— Mika Rantanen (@mikarantane) December 9, 2023
☔ Sur la période de 2 mois qui va du 15 octobre au 11 décembre, il est tombé jusqu'à 1263 mm de #pluie au #Falgoux à 950 mètres dans le #Cantal ! On note aussi 1105 mm au Mont-Dore (63), 1052 mm à Vallorcine (74) ou 1040 mm à Sewen (68) ! – carte @meteofrance pic.twitter.com/3zXPr5Gyg3
— Guillaume Séchet (@Meteovilles) December 14, 2023
UK has a bit of a squeeze in the pressure field tonight. 1016 vs 1040 with strong WSW winds in the N. These winds are drawing some pretty warm air for time of year and time of day/night up from the subtropics! Fresher in far S nearer the centre and where winds are less. pic.twitter.com/boKtn9dT2q
— MarkVoganWeather.com (@MarkVogan) December 16, 2023
Kinloss, Lossiemouth and Tain Range in Scotland reported new December record high daily min temperatures 0900 yesterday-0900 today
Rain and wind in the north are the main features now
Kinlochewe has had 141 mm of rain last 48hrs, and Brizlee Wood saw a 68mph wind gust recently pic.twitter.com/NvN178HB8A
— Met Office (@metoffice) December 17, 2023
Very warm in Northern Europe and in the Alps.
In SCOTLAND records of December HIGHEST TMIN. at 12.1C Kinloss, 11.9C Lossiemouth and 11.0C Tain RangeIn SWITZERLAND record of December highest Max on the Weissfluhjoch (2691m) with +8.1C. pic.twitter.com/RpR5S99oyi
— Extreme Temperatures Around The World (@extremetemps) December 17, 2023
NW winds continue to go through the gears tonight as the pressure gradient increases. 1051 high over Atlantic vs sub 976 (falling) low headed for Norway! pic.twitter.com/rBXK7wwRIP
— MarkVoganWeather.com (@MarkVogan) December 20, 2023
Got my shot in #Edinburgh at 4pm today of the #polarstratosphericcloud #nacreuscloud ???? pic.twitter.com/xNCBjUfOBw
— Laura Dodds (@LaursD1) December 19, 2023
Rough weather for Denmark and NW-Europe as #StormPia rapidly intensifies in the left exit region of the strong jet stream.
Quite a strong pressure gradient between the storm and the Azores High (88 hPa!). pic.twitter.com/n96sLMhPMo
— Mika Rantanen (@mikarantane) December 21, 2023
Historic in DENMARK:
It 's now a fact that 2023 is the wettest calendar year recorded in Denmark since 1874.As of 20th December morning, 906.6 mm has fallen since 1st January and more rain is on the way.
That despite a long dry spell in early summer with no rain for 22 days. https://t.co/TeiTvYOrVX
— Extreme Temperatures Around The World (@extremetemps) December 21, 2023
It has been a very windy start across the UK this morning with a yellow wind warning in force until 3pm today ⚠️
Take a look at some of the maximum gust speeds we have seen so far ???? pic.twitter.com/U6f2In97Uq
— Met Office (@metoffice) December 21, 2023
The formation of nacreous clouds requires temperatures close to −85 °C. Such temperatures have been observed today at 30 hPa altitude by radiosonde ascent in Lerwick, Scotland.
These temperatures are close to record lows for this time of year. https://t.co/lS6Z8b0FfU pic.twitter.com/WcMvTX6A9J
— Mika Rantanen (@mikarantane) December 21, 2023
GFS portrayed a jet streak of 207 kts or close to 240 mph between Iceland and Low Countries late this eve… The centre of #StormPia is now over the SE corner of #Sweden at 961mb. A 99 mph gust observed @ Thyboroen #Denmark (strongest in 8 yrs). Cairngorm 115 mph! pic.twitter.com/kA0YYV6fec
— MarkVoganWeather.com (@MarkVogan) December 22, 2023
A short time ago, this guy was clocking a ground speed of 683 kts, that's 785 mph over the North Sea en-route yo Leipzig. She's within a jet streak of near 240 mph… pic.twitter.com/42MFZs3wyW
— MarkVoganWeather.com (@MarkVogan) December 22, 2023
A powerful jet stream gives eastbound flights some impressive tailwind above the North Sea. Multiple aircraft have a ground speed of 650+ knots. Note that Mach 1 is 666 knots.
Those traveling from the US towards Europe are getting some excellent time savings. Map: @flightradar24 pic.twitter.com/VPrg1nlpvN— severe-weather.EU (@severeweatherEU) December 22, 2023
Waking to the first snow ❄ of the season @ MVW HQ. pic.twitter.com/X8tdkGqXNO
— MarkVoganWeather.com (@MarkVogan) December 23, 2023
Despite pouring it down all morning, the slushy, sloppy inch of snow is clinging on, helped by the fact it has yet to hit 1°C as of 11am. Thoroughly cold & miserable day to be getting last minute presents, groceries etc! Different story further south where it's 10°C warmer… pic.twitter.com/bhnkM2Cw2T
— MarkVoganWeather.com (@MarkVogan) December 23, 2023
Just 3 or 4 miles apart as the crow flies… 3.0°C here in Evanton vs 9.2°C on the Black Isle. pic.twitter.com/c3X0JojwuT
— MarkVoganWeather.com (@MarkVogan) December 23, 2023
Temperatures have been well above the December average today with a top temperature of 15.3°C, making today provisionally the warmest Christmas Eve since 1997 ????️ pic.twitter.com/FVawNpMfUl
— Met Office (@metoffice) December 24, 2023
Rain, sleet & snow has moved across parts of Scotland today
In the last hour Tulloch Bridge & Aviemore have both recorded a mixture of rain & snow, making it an official white Christmas this year ❄️????
For more info on how we declare a white Christmas ???? https://t.co/ZnhaClgZnU pic.twitter.com/IiMgNqG63R
— Met Office (@metoffice) December 25, 2023
#WhiteChristmas in #Aviemore. Wishing you a very Merry Christmas! pic.twitter.com/QfNWwF5Qtt
— Netweather.tv (@Netweather) December 25, 2023
Exceptionally high temperatures in #Ticino, southern #Switzerland, thanks to strong foehn wind.
Monthly records fell and we were only 1.3°C below the Dec. national record.22.3°C Locarno/Monti della Trinità
22.0°C Biasca
21.9°C Cadenazzo
21.3°C Lugano
21.2°C Grono
20.6°C Stabio pic.twitter.com/E0bn0TlHTw— Thierry Goose (@ThierryGooseBC) December 23, 2023
More monthly records in Italy.https://t.co/dFPZrOOvUF
— Thierry Goose (@ThierryGooseBC) December 23, 2023
25.2C yesterday at Cumiana (Turin Province) is the new official highest temperature in December in Northern Italy.
4 stations with 25C+ in Piedmont.
In Emilia 24.2C at Vignola.
Table below is courtesy of Arpa Piemonte. https://t.co/K3YuONMiGt pic.twitter.com/PGH4dtZUfH— Extreme Temperatures Around The World (@extremetemps) December 24, 2023
Record warm #Christmas in eastern #Austria ???????? with up to 18.6°C in Vienna, close to the national record for this day (19.1°C). @extremetemps @EKMeteo @ExtremeMeteo @severeweatherEU https://t.co/9S9dttgXAU
— Thierry Goose (@ThierryGooseBC) December 25, 2023
It has been a very mild 24 hours across parts of the UK
Provisionally this Christmas we have recorded the highest daily minimum temperature for Christmas Day on record, with both Exeter Airport and East Malling not falling below 12.4 °C pic.twitter.com/K3SvkSCLkZ
— Met Office (@metoffice) December 25, 2023
No Christmas day maximum temperature record, but with 13.6C recorded in the southwest it has been the mildest Christmas Day since 2016 ????️ pic.twitter.com/pZiYQFgGD1
— Met Office (@metoffice) December 25, 2023
Heavy Boxing Day snowfall in #Reykjavik, #Iceland this evening 26th December! Can’t get any better than this ???? #Snowfall
(Video via FJolagu on instagram) pic.twitter.com/Rx6mWF8CxO— WEATHER/ METEO WORLD (@StormchaserUKEU) December 26, 2023
This was NASA’s photo of Scotland yesterday afternoon, during a rare clear spell. This weather system is delivering a lot more snow today. By the weekend there’ll hopefully be ample reserves for good winter walking across much of the Highlands. pic.twitter.com/Hgeq16F12k
— Iain Cameron (@theiaincameron) December 27, 2023
Current conditions on the A9 at Drumochter. Winds gusting 112 mph over Cairngorm. #StormGerrit pic.twitter.com/fvPdB8ZtJJ
— MarkVoganWeather.com (@MarkVogan) December 27, 2023
#A82 Fort William Inverlochy nr Ben Nevis Hotel. Police Scotland have closed the road due to fallen trees and lighting column. BEAR teams are assisting.@trafficscotland @HighlandCouncil @PSOSHighland pic.twitter.com/XOL76iDSrz
— BEAR NW Trunk Roads (@NWTrunkRoads) December 27, 2023
#StormGerrit is just the latest to have a tropical connection… A very wet 2nd half to 2023 continues. #ElNino #WarmAtlantic pic.twitter.com/y65OUEzQ2a
— MarkVoganWeather.com (@MarkVogan) December 27, 2023
Could be a long day! #Drumochter A9 pic.twitter.com/OU378wePIh
— Bibby's of Ingleton (@Bibbyscoaches) December 27, 2023
Another day with a distinct N-S contrast… latest temperature/wind chill/wind gusts (kph). Blizzard conditions on high road routes… Gusting 123 mph over Cairngorm! #StormGerrit pic.twitter.com/PNP9hzRFWy
— MarkVoganWeather.com (@MarkVogan) December 27, 2023
#A9 near Dowally, local water course has burst, overflowing onto the A9@trafficscotland @PSOSTayside pic.twitter.com/Fn84Wq6GGO
— BEAR NW Trunk Roads (@NWTrunkRoads) December 27, 2023
Same spot which flooded during #stormbabet https://t.co/Y5w0L5jDb8
— MarkVoganWeather.com (@MarkVogan) December 27, 2023
The view on the #A9 in #Scotland near Dalwhinnie right now. Huge lines of stationary traffic and severe gales and drifting snow. Not moved for two and a half hours. Seen one snowplough so far. #StormGerrit pic.twitter.com/cxOg2tsKVK
— Dr Shaun Dellenty B’Ed/NPQH/FRSA/FCCT (@ShaunDellenty) December 27, 2023
I’ve plotted year to date rainfall in Heathrow, it has turned into a notably wet year #London.
Currently to 26th Dec standing on 752mm the 1991-2020 annual average is 615mm, so 122% of average.
Back to 1973 only 2000, 2002 & 2014 were wetter, and all these in past 23 years in… pic.twitter.com/SMRJfpCKag
— London & Southeast ???? (@TheSnowDreamer) December 27, 2023
American 777 insane landing at London Heathrow!
Caught during our livestream at @HeathrowAirport. Strong, gusting crosswind elements catching-out even the most seasoned pilots! Wouldn’t have liked being the NFP on this one ???? watch the flight surfaces ????Get involved: what’s… pic.twitter.com/PjfqhsQjX2
— BIG JET TV (@BigJetTVLIVE) December 27, 2023
Tempête Géraldine en images à Porspoder aujourd’hui.
De belles conditions pour admirer le phare du Four pour le dernier jour de l’année.
Passez de belles fêtes et à l’année prochaine !!! pic.twitter.com/h0e8BCGVSi— Le Moigne Adrien (@Adilemoigne) December 31, 2023
My Weather Station Stats for December 2023
MAX TEMP: 14.1C MIN TEMP: -9.0C WETTEST DAY: 40.69 mm PEAK GUST: 73.4 kph WET DAYS: 24 DRY DAYS: 7 MAX PRESS: 1024 mb MIN PRESS: 975 mb TOTAL RAIN: 170.60 mm AVG Temp: 3.9C
My 2023 Wx Station Stats
Warmest 28.1C (8 Sep)
Coldest -9.0C (3 Dec)
Wettest Day 60.40mm (7 Oct)
Wettest Month 257.05mm (October)
Driest Month 28.43mm (May)
Strongest Gust 78.8kph (17 Feb)
Highest Pressure 1041mb (28 Feb)
Lowest Pressure 971mb (14 Jan)TOTAL RAIN: 1,196.14mm pic.twitter.com/00O9b8o5s7
— MarkVoganWeather.com (@MarkVogan) January 1, 2024
Reasoning behind another ‘good monthly forecast’
In mid to late November we had an amplified phase 1 into 2 MJO which resulted in a firmly -AO/NAO pattern with cold Europe.
As expected however, the MJO continued to progress eastwards in the tropics but rotating through the warmer phases of 3, 4, 5 and 6.
So, as the cold arrived it also left and the jet stream over both Pacific and Atlantic wakened pushing a lot of warm, moisture rich air across North America as well as Europe.
My thinking was that towards the all important Christmas-New Year period, IF the MJO happened to continue it’s eastward rotation back in to phases 7, 8 and 1, then the return of colder was likely.
We are back in phases 1, albeit the colder air has been fighting warmth across much of Europe (as expected) and we find a north-south split over the UK as well as the continent…
Note it’s becoming more amplified into 1.
Correlation
After briefly entering the ‘null’ or less amplified state, it’s once again becoming stronger (more amplified equates to more influence towards the pole). Due to the previous comment, I would expect a slackening off of the polar jet over both ocean basins and a renewed period of large-scale height rises into the higher latitudes once again with return of the -AO/NAO.
Lo and behold…
Here’s the extended GFS ensemble
Note the height change over N Pacific and Atlantic as jet streams weaken and flip from negative to positive.
Day 0-7
Day 7-14
Day 14-21
Day 21-28
2m temperature anomaly
Day 0-7
Day 7-14
Day 14-21
Day 21-28
ECMWF Ext 30-day
I believe the active phase 1 response only properly impacts the 500mb pattern as we progress through week 1 of January and the ‘colder’ push only kicks in between 6-8th January, maturing mid month say from 10-20th January with either a continuation of the chill or a bit of a pull back to milder.
Sudden Stratospheric Warming?
As for what’s happening within the 10mb or upper stratosphere, the strong Eurasia to pole warming has begun.
The question is twofold, 1) do we see such a deceleration of the mean zonal winds to a point of reversal (constituting a true sudden stratospheric warming event) 2) If so, is the result a displacement, split or collapse of the polar vortex? These are all important questions, I believe we see either a major displacement or splitting of the PV rather than complete collapse.
Keep in mind that even with a Major SSWE, 70% of these result in significant UK/Ire/W Europe cold.
What actually is a Major SSWE? It’s a strong warming or wave breaking within the stratospheric layer which causes a slowing down of the mean zonal winds which circle the cold vortex usually spinning above the pole.
The strong warming from outwith the arctic forces the cold PV core to become displaced and as we’re observing now, is leaning towards the N Atlantic and Europe hence the widespread observation of nacreus or polar stratospheric clouds.
Insane Polar Stratospheric clouds over North East england this morning @FujifilmUK @metoffice @Lauratobin1 @Ross_Hutchinson @JenBartram @StormHour @BBCNEandCumbria @BBCBreakfast @bbcweather @itvnews @itvweather @TamithaSkov @MarkVogan pic.twitter.com/uI6qeasoAJ
— Steven Lomas (@StevenLomas10) December 21, 2023
Nacreous clouds require temperatures of below -78°C to develop, and due to the stratospheric polar vortex being displaced on our side, the conditions have been prime today for such widespread visibility of the phenomena!
On the topic of the stratospheric polar vortex, there are… pic.twitter.com/kBSP8JUQgC
— UK Weather Updates (@UKWX_) December 21, 2023
What do sightings of polar stratospheric clouds over NW Europe & discussion of a potential sudden stratospheric warming have in common?
The amplitude of mid/low stratospheric wave-1 is extremely high, shunting the vortex toward Europe. This may set things up for a future SSW. https://t.co/6DhMU75iba pic.twitter.com/59AZiKiDJ2
— Dr Simon Lee (@SimonLeeWx) December 21, 2023
This warming if strong enough can force a 50C temperature rise over the polar region with the ‘wave breaking’ becoming strong enough for the typical west to east winds to flip back on themselves and reverse. The warming within the stratosphere causes the stratospheric layer to expand which then forces the troposphere beneath to contract. This contraction of the tropospheric layer then forces pressure to build within the 500mb level or within the lowest 18,000ft of the atmosphere ultimately triggering a -AO and often -NAO. The whole process if stratosphere-troposphere coupling is successful takes bitter cold out of the stratosphere into the troposphere and then away from the arctic towards the equator.
IF and it remains an if, we see a Major SSWE and all of the above happens, the response comes typically 2 WEEKS after the zonal winds have reversed. It takes time for all the energy to propagate downwards through the lowest two layers of Earth’s atmosphere.
There could well be somewhat of a baton exchange between cold phases of the MJO (explained above) and SSW continuing if not strengthening a cold pattern for Eastern North America/W Europe.
The very wet conditions during particularly October and early November may have been a hint at the cold spell to end November, begin December and I wonder whether the most recent spell of very wet weather could be yet another hint at a coming cold pattern?
Conclusion
I suspect Atlantic resistance through the first week to 10 days but as heights are expected to build between Scandinavia, Iceland and Greenland I would think the jet pushes further south into France or Iberia. This should allow intrusions of polar or cold continental air to slide down from north or northeast presenting increasing threats of snowfall and colder conditions.
All in all I suspect a Slightly Colder & Drier Than Average January is Likely for the UK/Ireland and all of Northern Europe including Denmark, Northern Germany & Poland, Baltics & Scandinavia Inc Finland and Russia, Warmer & Wetter Across S Europe
FEATURED IMAGE CREDIT: Kairo Kiitsak
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