Derecho

Summer Sun A mean of 3.9C for yesterday suggests that Pershore College is indeed the site the Met Office use. If the 27th and 29th come in milder then there is still a chance we may only drop to 8.0C and set a new record but the odds are slim.

Daniel* Makes sense it is the more rural site. I had used Pershore college all this time as I thought that was the station. Ooops

Daniel* Is the Pershore station a different one to that on weatherobs? Your min obs for Rothamstad and Stonyhurst match the ones I had but the Pershore above looks like it dropped to around freezing? Edit: Ah yeah I stand corrected, the Pershore station just to the north was much colder so that brings down todays predicted mean to 3.5C

If we presume the 3.1C is the actual value for yesterday, the EC is going for: 25th: 3.9C (8.1C) 26th: 5.2C (8.0C) 27th: 3.3C (7.8C) - Pegged back significantly by a chilly night forecast 28th: 5.2C (7.7C) 29th: 7.2C (7.7C) - May rise if the chillier air from the west takes longer to arrive However it probably won't be enough, the mild weather from the 27th to 29th has been downgraded so 7.7-7.8C is likely the final figure. This is based off calculating the max and min temps on the EC from 0000 to 0000 and dividing by 2 which is probably the closest way to resemble the CET figures, I think I've read in the past it might be 0600 to 0600 though?

WYorksWeather Yesterday came in at 7.2C so quite a bit above the forecast I gave yesterday. 8.0C is definitely a possibility now, especially if the colder temps over the next 3 days have been overplayed.

Didn't realise I wrote this comment back before the Ukraine war started but it has unfortunately aged very well. We need more renewables! and the Ukraine war highlights it... the less we rely on the likes of Russia the better as it weakens their hand. It's a shame Trump will serve to strengthen it from next year.

WYorksWeather From the obs I can see, 5.9C is my best guess... but this is based off midnight to midnight obs.... Based on the EC 12z... 22nd: 5.9 (8.6) 23rd: 3.7 (8.4) 24th: 3.1 (8.2) 25th: 4.9 (8.0) 26th: 4.8 (7.9) 27th: 4.6 (7.8) 28th: 8.8 (7.8) 29th: 7.6 (7.8) So the 23rd and 24th look the only colder then average days now. 25th looking less cold as the low pressure is set to move across closer to the UK with air a little less cold. 27th is pegged back by the cold morning. The remaining days are set to have an average of 5.4C. If that mean comes in half a degree higher (5.9C) the record is gone.

Mean temps on the EC12z as close to possible to Stonyhurst, Pershore and Rothamstad on the 12z EC are as follows: 21st: 9.6C (8.7C) 22nd: 7.1C (8.7C) 23rd: 3.8C (8.4C) 24th: 3.2C (8.2C) 25th: 2.3C (8.0C) 26th: 2.7C (7.8C) 27th: 4.7C (7.7C) 28th: 8.7C (7.7C) 29th: 8.3C (7.7C) So the EC from the 23rd to 26th is a bit too chilly for us to beat the record. The minima on the morning of the 25th and 27th are pretty cold. Clear skies and slack winds being the culprit. If it is a bit cloudier then expected the daily means might hold up more but it'll still come in a bit short of 7.9C I reckon.

So looking at the 12z EC and trying to match the data to Rothamstad, Pershore and Stonyhurst as much as I can I get the following: Daily mean and monthly mean in brackets 20th: 8.7C (8.7C) 21st: 9.4C (8.7C) 22nd: 7.0C (8.6C) 23rd: 3.8C (8.4C) 24th: 2.9C (8.2C) 25th: 3.4C (8.0C) 26th: 3.5C (7.8C) 27th: 5.0C (7.7C) 28th: 8.1C (7.7C) 29th: 8.0C(7.7C) So just short of the 1779 record if the EC temperatures are right... we will see. This will at least be a useful litmus test to compare the EC point data to the observed temps. I think the minima may hold up a bit more then predicted on the back of this mild and wet spell but we will see. Personally I think we will just fall short of the 1779 record.

Daniel* Looks like this table is wrong then, strange it is that far out as in the summer it was pretty accurate.... Meteociel.fr - Tableaux ECMWF-ENS WWW.METEOCIEL.FR La météo en temps réel et prévisions météo pour la France, Observations météo, modèles numériques et logiciels météo (GFS, ECMWF, UKMO, GEM, AROME, ARPEGE, JMA) Looking at the WZ temps as well they tie in more with the figure you gave. The GFS data looks far more in line with the WZ anomalies so there is a problem with the EC tables generating on the website it seems, especially with the minimum temps. Based on the GFS 00z values a final figure of 7.4C is expected though that is cooler from Feb 27th-29th. Edit: Looking at the EC tables, unfortunately you can't get data directly from a point using this function anymore. The interpolation tab does some funny stuff. You can change it to point data... Meteociel.fr - Tableaux ECMWF-ENS WWW.METEOCIEL.FR La météo en temps réel et prévisions météo pour la France, Observations météo, modèles numériques et logiciels météo (GFS, ECMWF, UKMO, GEM, AROME, ARPEGE, JMA) But it says 'the grid point is 22.2 km from the selected point' at Rothamstad so it looks like it's just pulling data from nearby cities. Not a valid estimate anymore unfortunately.

Based on the EC 00z this morning with daily mean followed by rolling monthly mean in brackets: 20th: 9.7C (8.7C) 21st: 10.5C (8.8C) 22nd: 7.7C (8.7C) 23rd: 5.6C (8.6C) 24th: 5.4C (8.4C) 25th: 5.9C (8.3C) 26th: 5.7C (8.2C) 27th: 6.6C (8.2C) 28th: 9.1C (8.2C) 29th: 8.0C (8.2C) So even if the EC is cool biased it still breaks the record comfortably.

WYorksWeather A few days ago the EC had 8.6C to the 22nd whilst the GFS only had 8.0C from its forecast. Even the milder EC came in as an underestimate. If we end up as absurdly high as 8.8C then I think this mornings EC would be enough as the 27th-29th are mild. GFS cooler again but no surprise there.

I don't think you can really compare the El Nino's from any of those winters to this one. The January MEI values (which give a more comprehensive overview of ENSO state for those 4 winters and this one are as follows: 1973 - 2.02 1983 - 2.6 1998 - 2.2 2016 - 2 January 2024 only had an MEI index of 0.7... which makes it only the 32nd largest El Nino since 1871 (though the 3.4 region anomalies were a bit stronger). Indeed January 2010 had a value of 0.9. Jan 1969 and 1940-1942 also had higher or similar MEI values but those winters were very blocked. So I don't think ENSO is to blame for this winter, more a case of climate change and bad luck with the knock on effect of those crazy high SSTs to the SW of Spain leeching into Europe. Hopefully next winter will see a better roll of the dice. December 2022 was a decent effort for the first 20 days before the fine margins worked against us.

WYorksWeather Agreed, yesterday's CET is likely to have come in at around 9.9C according to the obs at Stonyhurst, Pershore and Rothamstad (though I calculated midnight to midnight mean). Both today, tomorrow and the 21st at least should see a daily CET in double figures (again). The 13.7C for Thursday was truly remarkable.

Looking at the output this morning from the 00z's, the GFS has the CET at a peak of 8.4C on the 21st whilst the EC has a CET of 8.6C. Oddly, even at short range the EC has milder minimums then the GFS. Is the GFS cool biased? After that it turns cooler but not for long on the EC and the CET holds out to 8.2C by the 29th. GFS has a longer run of average temperatures and the CET drops to 7.3C at the end of the month. So a record very much a possibility if the cooler maritime flow on the 23rd is only a blip.

WYorksWeather Stonyhurst is on Weatherobs and got to 13.96C a short time ago. Weatherobs WEATHEROBS.COM Global weather observations (METAR, SYNOP, BUOY, SHIP, TAF, CWOP) decoded to enable display of latest temperatures, weather, snow depths, precipitation, wind and wave conditions and more

Weather-history And then by the next winter we got a very cold and cyclonic pattern instead! Wouldn't mind a repeat...

Weather-history This is backed up by the SLP observations for that month which were very high (London and Paris). Suggests a February 1998 type month synoptically. There was some analysis done which suggests the Feb 1779 CET may be an overestimate though. Oddly January 1779 was even more anticyclonic but that ended up with a CET well below average.

Yup if a warm September causes a mild winter, then why not a warm October or mild November?

Has to be up there with the worst in my life time though I think 2007 has to edge it here because of the floods. The jubilee celebrations took place in weather that is as bad as you can possibly get for June. August was quite reasonable though and I think the weather for the Olympics was quite nice. Quite a few thundery days to keep things interesting, though the big plume in late June we was unlucky for. The storms went to our south through Lincolnshire. Just very dark clouds and constant distant thunder here. Easily the most unstable synoptics I can remember with some decent hail storms in the Midlands and a tornado in southern Lincolnshire with the chase footage looking like something out of the Great Plains in the US.

North-Easterly Blast Disagree, in fact the NAO signal during La Nina phases is actually stronger. According to the multivariate ENSO index the La Nina of 2022 was also pretty strong. As I said it's not fully clear but you'd expect that given Europe is far away from the ENSO region but ENSO does affect wider atmospheric circulation patterns and this has been in the scientific literature for some time now. What is also worth adding that isn't considered in this list is the type of La Nina ENSO event that takes place. El Nino Modoki events and eastern based La Nina's tend to be best.

North-Easterly Blast There have been some in the past but it's not a clear link. Past observations suggest that Decembers have a distinct +NAO whilst Januaries and Februaries are often more blocked. So Januaries and Februaries tend to fare better. Looking at all the El Nino's since 1870 using the Multivariate ENSO index: Over half appear to be backloaded whilst the others are mixed. The NAO in a December is often more positive (see table above) in an El Nino which is where the notion of 'backloaded' comes from. Often the worst synoptics of an El Nino winter come in December. The reverse is true for La Nina's. December 2010 and 2022 are good examples of cold Decembers followed by mild February's. So there is some link but other factors are of course at play.

It looks like we are heading for a Feb 1998 / 2019 type month where instead of the usual backloaded El Nino winter we are getting a blocked pattern that we are stuck on the wrong side of. Looking at the anomalies this week indicates there is blocking around in the NH but Europe is acting as a road block. Interestingly Feb 1998 also saw a cold NE Europe. The problem this time is that high pressure is nowhere near as expansive so whilst still mild it is unsettled instead. Looking at the Feb CET as it stands it is a remarkable 7.9C to the 10th despite that brief colder interlude in the middle of last week. Based on the 06z GFS it could be at 8.0C so the 1779 record may be under threat...

Metwatch I have to some extent, the years in which there was an El Nino I showed the El Nino composite (January 1987 for example)

For those who are intrigued some interesting MJO periods from the past. For each cold month the key analogues for the most amplified phases during that month. Oct - Dec 1981. December 1981 phases 5 and 6 Jan - Mar 1985. January 1985 phases 8 and 1 Feb 1986 phases 8 and 1 Jan 1987 - Phases 2 and 3 Feb 1991 -Phases 5 and 6 Dec 1995 - Phases 7 and 8 Feb 2005 - Phase 6 and 7 Jan 2010 - Phase 7 Phase 4 and 5 - Dec 2010 Feb 2018 - Phase 7, 8 and 1 A pretty good record there. Maybe not for Dec 2010 or Feb 1991 though. A lot of the times 'it failed' were because people read the composites incorrectly or assumed it would go into a favourable phase when uncertainty was high. No way are they bulletproof but they were just a tool to examine whether we could get out of a SW'ly rut and it did pretty well. To say it's something used by snake-oil salesmen is pretty harsh against the academic research that has gone into it.