virtualsphere

A quick and dirty comparison of September vs following winter CET from 1760 to 2015 (because Excel will only allow 255 entries on the chart) shows the relationship is all rather random aside from the few very warmest Septembers > 15.7 showing the following winters to be above 5C - probably not enough examples for a meaningful comparison as yet.

You'd be correct on that! Source: Climate Prediction Center - Monitoring and Data: Regional Climate Maps - Europe WWW.CPC.NCEP.NOAA.GOV

14.4C and 97mm please

Enjoying the sunshine compared to last July's drizzle but a bit too warm for me especially at night. Feels more oppressive than 2013 which is my benchmark for good weather at this time of the year, having said that I was able to work in an office in July 2013 which was much cooler than having to work in the bedroom! This summer hasn't been too bad here in west Wales, better than last year so far. I think we've got off lightly compared to those further east, it's been relatively dry here after the washout May.

Tough one to call at present, I'm going to risk a total bust by going for the rather unusual dry and cool combination - 15.1C and 32mm please.

Although my memories of the 1980s are a bit sketchy being a child at the time, I remember some fairly dry but rather chilly weather on a 3 week holiday to Scotland in August 1987 (I have a photo taken in a duffle coat with shorts at John O'Groats). I spent a lot of time outdoors so I'm sure I'd remember if any had been as consistently wet as 2012 here. These show 1985 as the wettest of the period, on a par with 2007 but not as wet as 2012: 1987 as the dullest, on a par with 2012 and less sunny than 2007 or 2008: Interestingly 1989 comes in sunnier than 2018 and everything else since 1995. Temperature is where the 1980s summers fall back, we've not had anything colder than that run of late 80s summers since in terms of mean temperature although looking slightly further back they weren't quite as cold as some of the summers in the 50s and 60s. Our recent poor summers don't fare as badly in that respect (if it's heat you like: I'm finding this week a bit too warm!) UK temperature, rainfall and sunshine time series WWW.METOFFICE.GOV.UK Time series graphs of climate variables for previous months, seasons and years

17.3C and 82mm please

Thanks, that sounds like a really fascinating project. I wondered about the data as getting historical records back that far seems challenging, and because the timescales for the data we have are so short in climate terms there are probably a lot of interesting natural cycles like this that we haven't yet paid much attention to. I've been wondering whether there's a dataset for average wind direction / speed, or average SLP in the UK over a specific period (e.g. a month, year etc).

Slightly off topic here but I'm curious as to when you did your dissertation and what data you used? I feel like there was a notable absence of easterly winds in the years up to around 2008/09, replaced by an increased frequency in easterlies in the 2010s, and it seems there has been an absence of northerlies in recent years until last winter - but it could just be my perception. Other than the volcanic activity, did you find any likely drivers for longer term changes in circulation patterns which particularly affected the CET?

It would be interesting to compare the average CET for the first halves of the months so far this year against others - quite a few months so far with a warm up towards the end after a cold start. June does look set to break that pattern though!

14.7C and 46mm please

The problem with May 2012 is the last 2 weeks were the only decent dry sunny spell of the entire 'summer'! Though I don't feel like this is a 2012 style year, for me more like 2013 but running a little later. If that holds then we could have a cold start to summer but a decent spell later on, perhaps end of July into August, a bit later than the nice July weather in 2013. Of course it could all surprise us as it often does!

Precipitation, relative humidity and soil moisture for March 2021 | Copernicus CLIMATE.COPERNICUS.EU

10.5C and 37mm please

Maybe I'm one of very few enjoying the current spell of weather? It's not felt too chilly here in west Wales, aside from first thing in the morning, and the sunny dry weather has been a very welcome break from the deluge of the 18 months prior to March (last April & May aside). We've been overdue a lengthy dry spell here and I'm hoping it will last into the summer this time, unlike last year!

It's quite bizarre how the last 3 months have all started with below average temperatures and no warmth being modelled in the longer term, only for very warm conditions to turn up after mid month. The near average CET returns this year are masking some interesting cold / warm switches and variations. April looks to start on a chilly note so could go in the same vein. I was caught out in March going low, so have plumped for a warmer April!

9.7C and 56mm please

5.3C and 48mm for me please.

It looks like the last time the annual CET fell below 9C without any winter month being below 2C (or indeed 3C) was in 1922. I was wondering if it could be done using 21st century months but without any of the extremes in the winter. I'm not quite sure how it's calculated but on the basis of purely averaging the months this should do it without any one month below 3C: Jan 21 (3.1), Feb 09 (4.1), Mar 06 (4.9), Apr 12 (7.2), May 13 (10.4), Jun 12 (13.5), Jul 11 (15.2), Aug 14 (14.9), Sep 15 (12.6), Oct 12 (9.7), Nov 16 (5.6), Dec 17 (4.8) That would be an atrocious summer though!

I'm sure we will but as in 2010 I suspect it would be driven by larger negative winter anomalies, as it seems much rarer to see significantly colder months from April to October - probably because our colder summer months are caused by a northerly influence which naturally has a longer sea track over warming waters. In winter, easterlies can still deliver continental cold, but as the continent warms in summer the same synoptics would likely be warm. It would be interesting to see what would happen if we ever had a significant cold SST anomaly to the north of the UK in the summer though. Best chance would probably be a sub 2C Jan / Feb and or Dec, colder March / Nov and then something cyclonic, wet and dull in the summer like July 2007 or June 2012. If we can go subzero for a month and / or get all three winter months under 3C like 2010 then we could still return some milder months during the rest of the year and end up below 9C.

June 1991 and to a lesser extent May 1996 were also chilly. I think June 1991 may be in the top 10 coldest but that's still 30 years ago this year.

This was my favourite Candlemas / Groundhog Day in recent times - the start of a memorable wintry spell. Here's an example from 2019 which goes against the rule. We had a dusting of snow but the rest of the month was mild and the CET finished at 6.7. Actually rather unusual here to get snow 10 years to the day apart!

2.6C and 70mm please

Woke up to this today... the biggest fall here since 2013. Hope others wanting snow get to see some of the white stuff as the front pushes through!

I've been looking at some charts from January 2013 - there are some differences between the 2013 SSW and the current one, I think 2013 was a split rather than a displacement warming, and the UK was in a stormy Atlantic-driven trop pattern prior to the SSW back then. My reasoning for looking at Jan 2013 though is that, unlike Feb 2018, there wasn't a massive block in place driving a 'beast from the east' but rather smaller wedges of heights to our north which delivered snow from areas of low pressure sliding underneath - a bit like the pattern currently being suggested by some of the models. We had some surprise snow from the 2013 set-up which was originally forecast to turn to rain and stayed as snow throughout. Looking at the GFS 12Z for T+72 - high latitude block developing over Greenland, low pushing underneath and also an arctic high in the middle of the vortex segments. Now compare this to 18th Jan 2013 - similar process underway but this time the high latitude block develops to the north of the UK towards Scandinavia which is more beneficial in keeping the UK cold than the current blocking which is further west. Here's the 22nd Jan 2013 and the GFS for T+150. I've rotated the GFS to show how the synoptics could look if the block had set up in a different place! Worth taking a look at the charts for the rest of Jan and Feb 2013 before that famously cold March. The high latitude blocking ebbs and flows, and we get synoptics like this - for the UK, not dissimilar to what is being suggested for us towards the end of the week, even if the rest of the NH pattern is a little different. Still a lot of interest left this winter I think, given how the rest of that winter / spring turned out!