SqueakheartLW

BANK !!! I'll take this outcome from the SSW

A few potential split runs showing on both GFS 12z and GEM 12z GFS 9 of 32 members here with potential split vortex, hope this increases as we get nearer with 23 of the 32 looking like a displacement event on this run. GEM Again 9 members with the GEM only this time a higher proportion with only 21 to go on so GEM more keen for the vortex split on the 12z's

More like these please for warming peaks Also apart from the best one you have shown here there are a couple more on GEM that look like they are possibly headed the same way

An update on the SSW for me today and like yesterday it is based on the GFS 12z and GEM 12z GFS 12z GFS 12z is really churning out the toasty warm charts today That's 9 of 32 members of the 12z going for a +4C peak warming but my favourite one is P29 below A nice toasty +12C warming on this member GEM 12z GEM has this nice +384h chart showing on P07 This is the only chart on the 12z's between GFS and GEM that came anywhere close to a split vortex chance Not as many toasty +4C or above warmings on today's GEM 12z compared with yesterday with only two +4C's It does make up for it by having a +8C warming chart on P14 Analysing all members of both GFS 12z and GEM 12z (20/12/2023) GFS +12 29 +4 02,07,08,11,18 21,26,28,30 0 Op,Ct,03,06,09 10,14,20,24,25 Average GFS Warming Peak = -0.250C (-2.625 yesterday) -4 01,04,12,13,15 (Upgrade of 2.375C compared with 19/12/2023) 17,19,22,23,27 -8 05,16 GEM +8 14 +4 04,17 0 01,05,07,08 13,15,20 Average GEM Warming Peak = -2.095C (-2.286 yesterday) -4 Ct,02,03,09,10 (Upgrade of 0.191C compared with 19/12/2023) 12,16,18,19 -8 06 -16 11 Good news for those wanting a more toasty warming it would seem as both GFS and GEM have upgraded the peak warming temperature, especially the GFS. Seems even more nailed on today and what was telling is how every single member of both GFS and GEM that goes far enough out had a warming of some degree on it.

GFS 12z GFS 12z P07 looks great at the end Nice signs that a split could occur here Also the warmest warmings from the GFS 12z too. GEM 12z A nice attempt to split the vortex here on P09 GEM looks even more keen for a toasty warming 6 of 21 members going for +4C Analysing all members of both GFS and GEM GFS +4 11,22 0 Ct,01,06,08,10,13,16 18,21,23,28,29,30 -4 02,03,04,05,07,09,12 Average GFS Warming Peak = -2.625C 15,17,20,24,25,27 -8 19,26 -12 Op,14 GEM +4 Ct,01,06,14,15,20 0 04,11,18 -4 02,09,13,16,17,19 Average GEM Warming Peak = -2.286 -8 03,05,07,08,10,12 At present it seems both GFS and GEM are very keep for a significant warming with the GEM marginally warmer with the peak than the GFS but there's very little in it.

Looks like it when you compare the 10th Jan 2013 10mb strat chart with the 23rd March 2013 500mb trop chart I have roughly marked out where the trop ridging is and where the troughing is. Looks very similar to the strat chart from over 2 months before it, compare this with 14th Jan 2013 below and there's no resemblance to the strat pattern at all Generally still have the polar vortex in polar regions but split a little bit but nothing like the strat pattern.

Definitely a split with Jan 13. Main warming starts on Siberian side and peaks on 2nd Jan 13 at +12C This warming pushes into the pole and starts stretching the vortex by 8th Jan 13. Signs of another warming showing up here on the US side as well. Must be a wave 2 event taking place. This second warming intensifies and combines with the first main warming and starts splitting the vortex by the 9th Jan 13 Major warming complete by 10th Jan 13 with vortex split and a band of warm strat temps crossed between the US and Siberia

It would be a remarkable feat to see all 12 months above the 1961-90 average but what I think 2023 doesn't deserve is for us to see yet another 11C CET mean year. I have been creating the rolling CET for 2023 for some time now and it is looking like a very close run thing as to whether we not only get all 12 months above 1961-90 but we also get another 11C year. Now looking at the table above you can see how we are doing against the previous top 10 years. Currently we are tracking a little behind 2022 but we are very close to 2014. So what now looks very certain is that we are going to see a top 3 finish for 2023. We are provisionally at 11.190C up to 16th December and if the 17th December GFS 00z mean predictions come true then 2023 will finish in 2nd position on the mean CET record. We will also set a December 2023 mean CET of 5.855C. We will have achieved based on this prediction Another 11C CET year out of what seemed no where considering much of the year has been unremarkable except for June 2023 and the September heatwave. 2022 deserved it's 11C CET mean but to me 2023 doesn't and it would be such a shame for an unremarkable year overall to take another 11C CET mean. All 12 months above 1961-90. A December 2023 CET of 5.855C would easily see this record fall. We should have done this last year as 2022 deserved it but 2023 is going to steal this remarkable feat from an unremarkable year for big extremes in the UK at least. A top 2 year immediately following the warmest year on the CET record last year. Again undeserved really considering how 2023 has been but it is only June 2023 and 10 days of September 2023 that have really put us in this position.

Bring those negative anomalies down to the trop please Can't be too much to ask for surely

GFS 12z best warmings GEM 12z strange vortex stretching and weakening charts just like yesterday. No idea what is causing this.

When seeing lots of individuals over in the mod thread getting annoyed with the potential loss of blocking and cold to end the year need to think that we don't want to see a blocked pattern just prior to and during the potential SSW. If we have ZONAL BEFORE and DURING the SSW there is a much GREATER chance that the effects of the SSW will FLIP the pattern from ZONAL to BLOCKED. The reverse also holds true where a BLOCKED pattern BEFORE and DURING the SSW there is a much GREATER chance that the effects of the SSW will FLIP the pattern from BLOCKED to ZONAL. Example ZONAL to BLOCKED due to SSW Early 2013 was a perfect example. We went somewhat blocked in early December 2012 before we entered a more zonal period mid December to early January prior to and during the SSW which is exactly what we wanted as we then saw the result with the pattern flipping to generally blocked from mid January 2013 to early April 2013 and generally colder than average with some snow at times. Example BLOCKED to ZONAL due to SSW In contrast to this is winter 2001/02. We had a blocked and colder pattern just prior to and during the SSW. The result was that we lost the blocking signal early January 2002 and we FLIPPED back to default ZONAL for the rest of the winter. On this occasion the SSW RUINED the rest of the winter.

GFS looks to be odds on for this warming at the end of its ensembles at present but I can't say the same for the GEM although it has some interest in another way Here's the 4 best GFS 12z warmings +4C +8C These are at the warmest end but the main warmings appeared to peak more around -12C on the 12z The GEM has NO warmings showing at all but what is interesting on the GEM 12z is the number of ensemble members that are really stretching out the cold temperatures at the back end of the runs. I have included the 4 best ones below There were several more members doing something similar but slightly colder than these ones. These look close to splitting the vortex despite no actual warming showing up.

GFS 12z P17 would be the perfect run into Christmas 2023. The 2m temps are based on my location in Scunthorpe. Adjust accordingly for your own location of course but the whole UK more or less follows the same changes. Tuesday 19th December 2m Temp Min (Scunthorpe) = 4.3C 2m Temp Max (Scunthorpe) = 7.3C A dry and most likely cloudy day when looking at the 2m temps for this day with an above average 2m min but slightly below average 2m max suggesting an inversion situation here but change is already brewing up to the north with those colder uppers and the trough waiting to push down towards Europe. Wednesday 20th December 2m Temp Min (Scunthorpe) = 4.8C 2m Temp Max (Scunthorpe) = 7.9C The high pressure starts retrogressing out into the Atlantic, opening the doors to the Arctic. A cold front sweeps south during this day. Despite the lower uppers the day is in fact slightly milder than the 19th due to more mixing out of the air. The proper cold air doesn't arrive in Scunthorpe on this day which is why 2m mins and maxes are still mild. Thursday 21st December 2m Temp Min (Scunthorpe) = 1.6C 2m Temp Max (Scunthorpe) = 4.1C The UK is now into the cold Arctic airstream by the 21st with wintry showers a threat on exposed coastlines with the main snow risk in the north. The -5C 850hpa isotherm has swept through the country with the -10 850hpa isotherm waiting to the north. Most southern areas and inland areas getting a dry, sunny but cold day. Colder air is waiting to arrive however. Friday 22nd December 2m Temp Min (Scunthorpe) = -0.6C 2m Temp Max (Scunthorpe) = 1.3C An even colder day than the 21st with maxes struggling to get much above freezing (Scunthorpe +1.3C) with overnight air frosts. The snow threat has reduced in the east for now with the slight change to more of a NNW wind instead of a northerly. However some western areas are now at risk of snow showers coming in off the Irish Sea. A very cold winter solstice 2023 day too. Saturday 23rd December 2m Temp Min (Scunthorpe) = -2.4C 2m Temp Max (Scunthorpe) = 0.8C An even colder day sees the day before Christmas Eve almost an ice day in Scunthorpe but further north it may well be an ice day. A couple of troughs have formed in the flow here. One in the English Channel threatens a snow risk south of the M4 whilst another looks to be descending down across Eastern England giving a heightened snow risk for these areas (Including Scunthorpe) Christmas Eve 2m Temp Min (Scunthorpe) = -2.9C 2m Temp Max (Scunthorpe) = -0.6C Christmas Eve sees an ice day for Scunthorpe at least but most likely across a large part of the UK as well after the dumping of snow in some places on the 23rd. Christmas Eve itself sees the snow threat reduce once more to just showers in exposed locations towards the coast Christmas Day 2m Temp Min (Scunthorpe) = -3.0C 2m Temp Max (Scunthorpe) = -0.7C The big day itself looks very interesting with that trough that has moved up from France into southern UK. An ice day Christmas Day for Scunthorpe at least but the main interest here could be the widespread snow event associated with that trough and with the +0C 850hpa isotherm basically on the south coast then the snow could cover a large part of England. A nice white Christmas here on GFS 12z P17 if it came off. Even Scotland could get a white Christmas in more eastern parts with that flow from off the North Sea too.

For those of us like me who have really missed the GFS extended run after it had played up for what seemed like an eternity can be pleased now it appears to be back up and running once again I always liked looking at the runs post +384h just for fun and to see what crazy or unrealistic scenarios it was churning out. Just for fun here's the coldest or potential cold or snowy Christmas Day charts Cold and possibly wintry P01 P05 P07 P12 P14 P25 Battleground / Southerly Tracking Low options P03 A good few there to look at. Note P02, P04, P08, P10, P16, P17, P18, P21 (Worst one), P22 and P24 are horror show Christmas Day charts for coldies all with 850hpa temps widespread over the UK above 0C. P21 as indicated is the worst with +5C isotherm widespread over the UK. I don't recommend you view these unless as a coldies you want to throw up.

I notice this is starting to be a constant signal for vortex weakening on the GFS Maybe we won't have a raging vortex for much longer.

Now we know how to guarantee the UK a cold winter every year. Not good news for Canadians though.

The extreme high maxima in summer have typically come under ENSO Neutral or Weak/Moderate La Nina state during the summer itself. Aug 2003, July 2019 and July 2022 were all under Neutral or Weak/Moderate La Nina during the summer itself. The more generally warm summer months which set a monthly high mean seem more likely under El Nino or a developing El Nino. July 2006, Aug 1997 and July 2018 were all under developing El Ninos. Ongoing El Ninos don't often produce a record warm or daily extreme max and El Nino to La Nina summers typically turn out quite poor. 1998 and 2007 are perfect examples of this.

I think many places had an ice day for Christmas 2010 if I do recall and the mean CET daily value for the day was -5.9C. In fact 2010 was the last time we had notable cold leading up to Christmas, on the day itself and for a short time afterwards as well with a string of sub zero daily CET means from the 17th up to the 27th, the period averaged -3.93C. 2009 wasn't quite as cold for the period 24th to 31st as you might think and was in fact less cold than the equivalent period in 2010. 2009 was 1.91C for that period compared with 0.39C for 2010. The Christmas to New Year period in 2009 was in fact the less cold period that was sandwiched between the pre Christmas cold from the 17th to 24th and the post New Year cold from 4th to 10th January 2010. The last week of 2000 also averaged colder than 2009 as well at 0.95C. The ideal lead up to, Christmas to New Year period and early 2024 period for me The perfect build up for me would be: 2009 from 17th to 24th December 2000 from 25th to 31st December 2010 from 1st to 10th January 17th 1.90C 25th 2.90C 1st -0.50C 18th -0.90C 26th 1.10C 2nd 0.30C 19th -2.00C 27th 0.90C 3rd -0.60C 20th -1.80C 28th -0.20C 4th -3.40C 21st -0.80C 29th -1.90C 5th -2.70C 22nd -1.40C 30th -0.80C 6th -0.50C 23rd -0.30C 31st 1.70C 7th -4.60C 24th -0.40C 8th -3.70C 9th -2.10C 10th -1.20C This is a broad idea of what I would want but if I wanted to be even more specific I would substitute 30th and 31st of 2000 and 1st to 3rd January 2010 for 30th December 1996 to 3rd January 1997 for extra snow. However the average mean CET for the singled out 3 periods above is a decent -0.66C so a nice sub zero lead up to, Christmas and New Year and opening to 2024 would do me nicely.

It's tipped even more towards modoki again today. A big jump in the anomaly in region 3.4 since just yesterday and a bit more cooling again in 1+2 What we really need however to make it a true modoki event is for region 4 to be somewhat warmer than 1+2 and Nino 3 to also cool a little bit too

I'm dreaming of a White Christmas. If this proves true we look to be in with our best chance for years

How will 2023 as a year finish in comparison to the top 10 years on the CET record Currently up to the latest date of 15th November 2023 we are provisionally in 2nd position, just ahead of 2014 with only 2022 ahead of this year at the current stage 15th November 2023 1 2022 12.069 7 1999 11.389 2 2023 11.731 8 1949 11.324 3 2014 11.655 9 2011 11.274 4 1990 11.508 10 2002 11.261 5 2020 11.469 11 2018 11.233 6 2006 11.406 Assuming the estimated CET mean values from the latest GFS 00z for the rest of November 2023 come true this will give a November mean of 7.8C. If this proved true then 2023's rolling mean would be 11.519C at the end of November 2023 which would still place us in 2nd position just ahead of 2014 with only 2022 higher than this year. Below I have what the average December CET mean would need to be based on the above in order to place above 2022, between any of the top 10 as well as the value required in order for us to fail to set a top 10 year. Year Category 2023 Provisional CET mean Details Dec 2023 = 9.67C (Dec 2015) 11.363C (+0.214C above 2022) ANNUAL CET MEAN RECORD SMASHED Dec 2023 = 7.17C or more 11.150C or more NEW ANNUAL CET MEAN RECORD SET 1 - 2022 Dec 2023 = 7.15 to 7.16C 11.149C 2022 RECORD ANNUAL CET MATCHED Dec 2023 = 4.97C (91-20 Mean) 10.963C (Easy 2nd position) 2022 RECORD SAFE - 2014 DOWN TO 3RD Dec 2023 = 4.80C to 7.14C 10.949C to 11.148C 2ND POSITION SET - 2014 DOWN TO 3RD 2 - 2014 Dec 2023 = 4.79C 10.948C 2014 ANNUAL CET MATCHED Dec 2023 = 3.80C to 4.78C 10.864C to 10.947C 3RD POSITION SET - 2006 DOWN TO 4TH 3 - 2006 Dec 2023 = 3.79C 10.863C 2006 ANNUAL CET MATCHED Dec 2023 = 2.50C to 3.78C 10.753C to 10.862 4TH POSITION SET - 2020 DOWN TO 5TH 4 - 2020 Dec 2023 = 2.49C 10.752C 2020 ANNUAL CET MATCHED Dec 2023 = 2.05C to 2.48C 10.716C to 10.751C 5TH POSITION SET - 2011 DOWN TO 6TH 5 - 2011 Dec 2023 = 2.04C 10.715C 2011 ANNUAL CET MATCHED Dec 2023 = 1.64C to 2.03C 10.680C to 10.714C 6TH POSITION SET - 2018 DOWN TO 7TH 6 - 2018 Dec 2023 = 1.62C to 1.63C 10.679C 2018 ANNUAL CET MATCHED Dec 2023 = 1.41C to 1.61C 10.661C to 10.678C 7TH POSITION SET - 1999 DOWN TO 8TH 7 - 1999 Dec 2023 = 1.40C 10.660C 1999 ANNUAL CET MATCHED Dec 2023 = 1.35C to 1.39C 10.656C to 10.659C 8TH POSITION SET - 1990 DOWN TO 9TH 8 - 1990 Dec 2023 = 1.34C 10.655 1990 ANNUAL CET MATCHED Dec 2023 = 1.20C to 1.33C 10.643C to 10.654C 9TH POSITION SET - 1949 DOWN TO 10TH 9 - 1949 Dec 2023 = 1.19C 10.642C 1949 ANNUAL CET MATCHED Dec 2023 = 0.95C to 1.18C 10.622C to 10.641C 10TH POSITION SET - 2002 DOWN TO 11TH 10 - 2002 Dec 2023 = 0.94C 10.621C 2002 ANNUAL CET MATCHED Dec 2023 = 0.93C or lower 10.620C or lower 11TH OR LOWER SET - NO TOP 10 SET Dec 2023 = -0.69C (Dec 2010) 10.482C NO TOP 10 SET

2000 is a good match for position in the solar cycle as well as an odd cycle too and an EQBO winter too. The major difference is ENSO which was La Nina in 2000 compared with El Nino now. 2009 is a better match for ENSO as well as QBO but a poor match for solar cycle position and is in an even cycle as well.

I'll take this to open up December BANK !!!

Hope this puts a jinx on the mild dross we often get and then we can look forward to you getting this wrong and we have the coldest winter for quite a few years, a 2009/10 redux perhaps or another 1995/96 would do fine as well except swapping out the mild weather of January 1996 for the first 20 days of January 2010 instead. If I wanted a perfect combination of these 2 winters I'd take it as follows December 2023? First half of December 1995 followed by Second half of December 2009 January 2024? First half of January 2010 followed by Second half of January 1996 February 2024? Have less preferences here as both Februaries saw little snow for me. 2010 had a frontal event early in the month and another one later on in the month. 1996 was cold to start before some snow showers later in the month.

I particularly remember one of these headlines in autumn 2013 saying winter 2013/14 would be the COLDEST and SNOWIEST for DECADES. Think we all know how that one turned out don't we