SqueakheartLW

We don't really want a repeat of any of the winters from 2013/14 onwards to be fair. Although 2017/18 had the beast, 2020/21 had a few on/off moments and December 2022 had the early cold there has been little proper winter weather outside of these. However much I'd love to see a 1962/63 winter just so I could experience it I'd be surprised if we came anywhere close to this. A 2009/10 or 1995/96 repeat would be nice however or another December 2010. The Christmas to New Year period from 1996/97 would also be good to see again. I certainly don't want a 2013/14, 2015/16, 2019/20 or a 2021/22 repeat. All of these winters were dire in similar ways and very devoid of anything cold or snowy. Don't know which of these winters is the worst one.

Nice charts there that I hope verify BANK !!! Maybe we are starting to see more charts like this since the Nino forecasts got toned right down to moderate.

This looks interesting in regards to winter prospects and for me this looks rather mixed. Want the good or bad news first? Good News (Possibly) Areas 1 and 2 - These recent SST anomaly changes in the last week all to me look like potentially good news for the up coming winter. Notice all of those blue getting colder areas in the eastern tropical Pacific ENSO region and those orange getting warmer in the western tropical Pacific ENSO region. Is this finally the sign that this El Nino is now beginning to shift from the current EP status to more of a CP status? I hope so and also hope we can even achieve modoki status as well but this may be too much of an ask before the latter stages of the winter which sours the good news to an extent which is why I have possibly in brackets in the title to this section. Bad News Area 3 - Indian Ocean IOD The recent SST anomaly changes here all look like bad news for a colder winter as all significant +IOD winters generally come out milder than average and to see mostly blue getting colder anomalies in the eastern Indian Ocean and orange getting warmer ones in the western Indian Ocean isn't a promising sign for the winter. We don't want to end up with another 2019/20 repeat of the "Polar Vortex of Doom" winter do we? Summary A bit of a mixed signal here with the ENSO signal shifting more favourably for cold whilst the Indian Ocean generally less favourable. It all depends really on whether ENSO or the IOD ends up the dominant driver of the two.

Significant +IOD events seem to occur most often with EP El Nino's or sometimes non modoki CP El Nino's on occasions. 2019/20 seems to be a big outlier considering ENSO was neutral in that season. There is a difference between EP, CP and modoki El Nino's and a lot of us assume all CP events are modoki as well. Modoki events are measured on the difference of the anomalies between Nino 4 and 1+2 whilst EP and CP is the difference between Nino 4 and Nino 3. Therefore we have several El Nino types: Standard EP El Nino (Nino 3 and 1+2 warmest anomalies) Modoki EP El Nino (Nino 3 warmer than Nino 4 but Nino 1+2 cooler than Nino 4) Standard CP El Nino (Nino 4 and 3.4 warmest anomalies but 1+2 not much cooler) Modoki CP El Nino (Nino 4 and 3.4 warmest anomalies. Warmer than Nino 3 and much warmer than Nino 1+2) Basin wide El Nino (All 4 Nino regions close to the same anomaly) Standard EP El Nino's have greatest chance of significant +IOD events with modoki CP El Nino's the least. 1997 is a great example of a Super EP El Nino combined with significant +IOD. 2009 is also El Nino but a modoki CP event and barely registers anywhere on the IOD, just above neutral but not enough to be defined as a +IOD event.

"September, the warmest CET month of the year? Only occasion that happened was in 1890 Both June and September warmer than the July and August in between them? That would be even more remarkable" Just read the above in the September CET thread. Rather interesting fact this one that it happened in 1890 We all know from CET records what happened in December 1890. Hope we can see a repeat of that month to open up winter 2023/24

Predicted September CET's based on today's GFS 00z run Like my previous example of this I have yet again used the 2m temp mean as well as the coldest and warmest members as well. Today the cold member is P22 and the warm one is P16. The result is below. A wide range for the possible CET outcome here. Average (Run Mean 14.9C) - Using the 2m temp ensemble mean the rolling CET does drop away but by the 27th it is still above 17C at a warm 17.156C. It would seem based on the mean at present that a 17C September is currently not on the cards but it wouldn't take much of a shift upwards to bring this possibility into play. Also we are toying here with the possibility of not only beating September 2006 but also June 2023 as well for the warmest month of the year. Warm (Run Mean 17.1C) - Using the 2m temp ensemble member P16 the CET does still drop away but by a much slower value so that by the time the 27th arrives we are still at a balmy 18.448C. This would see the record smashed as well as the possibility of a 18C September. If we do end up with another warm or very warm spell then 17C would most likely be certain with 18C a possibility. Cold (Run Mean 12.8C) - Using the 2m temp ensemble member P22 the CET takes a bit of a nose dive, so much so that by the time the 27th arrives the mean drops down to 15.900C. This is still a respectable value for a September but no where as ridiculous as the projected values for the warm member or the ensemble mean. For those of us who want to avoid a warm September then P22 is the member we want to be banking on.

I'm starting to think a 11C CET year could be back on again if we get a 17C or warmer September. September 2022 wasn't that warm in the end due to a 2nd half of the month cooldown and if we go on to have October and November 2023 above +2C on the anomalies then it would only take a December slightly above average to achieve another 11C CET year due to the colder than average December 2022. A rather sobering thought that after setting that new 11C CET year that another one could be on the cards this year, whether we beat 2022 or fall short of it but still finish 11C or higher. Will have to hope the warm September / mild winter theory doesn't hold out. We would hope to see a 1659/60 repeat. September 1659 was a 16C month then winter 1659/60 was colder than average.

You can guess what will happen now you've said this and written off a 2009/10 style winter A 2009/10 redux will now be certain

Maybe best to get the December 2015 anomaly out of the way now in September so by the time winter comes we can see negative anomalies instead.

I think we'll struggle now to get anything below 16C by the end of the month. A good guess if we go back to around average would be around 16.5C meaning 2006 should be safe but if we get another warmer spell then 2006 looks in danger of falling. Also what are the chances we get a 17C September or even beat June 2023 to set the warmest month of the year in September. That can't happen very often, especially after average or above average summer months before it. GFS 00z Model runs to predict possible rolling September CET Using these three 2m temp runs I will create 3 possible scenarios of how September could play out up to the 25th. The 2m temp mean, P05 and P06. Average Using the 2m temp mean we get the following out to the 25th September Still a very respectable 17.188C by the 25th if the GFS 00z 2m temp mean plays out as shown here. The yellow numbers are provisional CET values and the green for average values are in for the 10th to 25th. This puts us very close to 2006 at this stage with 2023 only a small margin warmer but looking like we'll drop below it before the end of the month. Coldest member - P05 How will September 2023 possibly pan out if we go cooler than predicted and follow a route similar to P05? The result is below. With using the coldest P05 member and colour coding these figures blue for cold we can see what a difference this makes to the rolling September CET with a value at 15.924C by the 25th. Still a warm value for September but at least not so ridiculous. This also places us below 8 of the top 10 years by this stage with only 1895 and 1929 still provisionally below 2023 if this coldest run were to prove the correct one. Warmest member - P06 Now how ridiculously warm could September 2023 look if we do something similar to what is showing in P06?. The result is below. With using the warmest P06 member and colour coding these figures red for warm we can see how ridiculously warm September 2023 could possibly turn out if we do indeed bring in another warm or very warm spell later in the month. This particular run leaves a provisional rolling September 2023 CET of a whopping 18.248C by the 25th which would effectively guarantee the 2006 record is smashed by a country mile and would possibly not only guarantee at least a 17C September but would be threatening a 18C September. This would be the December 2015 equivalent of a September month if this were to come off.

Hope those in the great north run have some boats ready

LOL

Talking of Christmas A nice pre Christmas cold snap on CFS 06z 9 monthly today

Yet another model with Greeny blocking and a NE Pacific trough and Azores troughing too. Yet another 2 fingers stuck up at the CFS which looks to be out on its own so far for September updates. Do they have individual monthly charts from this model too are all of them these 3 month ones?

Think someone forgot to switch off the Northern Lincolnshire storm shield. It's struggling to get out of South Yorkshire

Lightning maps has gone mental around my part of the world This has also appeared just to the west of Scunthorpe too Looks like I'm in for something here

An extraordinary start to September here and having 5 of the 8 days so far with CET means above 20C as well We are now pulling well clear of any of the Septembers that went on to finish as a top 10 September on the CET mean and I expect the CET mean for today to come in above 20C as well and will very likely be the last one that does but tomorrow could be a close call for this. After that sub 20C looks certain.

Could the 36C September max temp record be under threat now. Never thought that was going to be on

If you want one Bartlett man Here you go LOL I'd much rather have this

You know once someone has uttered that dreaded name they jinx the up coming winter LOL

I know other years that started warmer are missing but when looking out for a possible top 10 September the best years to include are the top 10 CET mean Septembers. After all its not how the month starts on the rolling mean but where we are late in the month that counts. How we compare to 2006 is what I'll be particularly looking at for a record warmest chance.

After just 5 days of the month on the provisional CET September 2023 is already ranking ahead of all of the top 10 Septembers on the CET record between 1772 and 2022 as shown in the table below. Positive anomalies show 2023 ranking warmer than the year whilst negative ones show 2023 cooler. As can be seen we are already above all of these Septembers. Below we have how 2023 is comparing to these top 10 Septembers day by day. The top 5 rows already have the provisional CET values on the left highlighted in yellow. Below this I have included the average GFS, ECM and GEM 2m temp mean mins and maxes averaged for each day across all 3 models and this predicted CET value is a mean of all 3 models put together. It has predicted a CET mean daily value for today (6th) of 20.1C. I feel this could be a slight underestimate however and the high running means around the 10th to 12th over 20C could end up even higher when we do get to these. The other notable thing here is how far 2023 is predicted to get ahead of the top 10 Septembers if the models prove correct. However we start falling back towards the top 10 by the 21st but still have a rolling value of 17.710C if these models runs are spot on.

The first one was I think on the 1st or 2nd. I replied to it and it should be in my comment history LOL. It's so funny when they do it on the first day of September. Wonder when we'll have "winter is over" posts in August?

Not looking good if this warm September / mild winter theory holds true yet again but imagine the irony if this very warm start to the month results in our first ever 17C CET September or even the possible chance that September ends up warmer than June 2023 and ends up the warmest month of 2023.

Like that deep blue over the NE Pacific. Makes a change to the dreaded red blob we have got used to seeing on the winter output. The -NAO signature looks good here and at least it looks like it isn't west based. Its also clear to see the EP El Nino signature here with the blues in the eastern tropical Pacific and the oranges over the western Pacific and Indonesia.