LetItSnow!

Scorcher I checked and the precipitation charts show a big blob of rain over Scotland early in the day for some reason and into northern England so is it picking up a weather front grazing the top of the high, limiting temperature via cloud cover? Seems unusual. I would have expected decent thickness, uppers between 6-8C and strong May sun with light winds to give widespread 20-25C maxima.

Blob of rain on the way. The torrential rain associated with the thunderstorms on the 2nd, some patchy bits here and there and this upcoming rain will make sure that May 2024 won't be an arid month here at least! Signs of a pressure break around the 13th/14th making me wonder if May 2024 will be another wet one to some degree. Of course a persistent high pressure system in the second half could put rest to that idea but already I think it's not impossible for it to happen again.

GFS left, ECM right. Subtle differences but both looking unsettled by early next week with weakenign pressure. GFS would probably be very wet with areas of rain and thunderstorms meanwhile the ECM would be more frontal rainfall. Details of this type are not worth looking at 8 days ahead of time. The GFS has more of a well defined high up into the Barents Sea leading to more of an undercut. The ECM has more of a general area of low pressure that crashes into Scandinavia which we get pulled into. In terms of the ensembles, the pattern differences also show up. The GFS may be hinting at some members taking that undercut and stalling it so don't be surprised if some very warm, humid and thundery runs show up around the 13th-16th time frame. The ECM ensmbles look cooler though with much less of a Scandi high signal and look a bit more blocked. A lot to be resolved but one thing looks clear, it's probably going to turn more unsettled early next week with rain and maybe even some thunder, but whether it's due to a battleground/heat pump scenario, or cooler with low pressure around, it's yet to be solved. No extremes in temperatures either way being shown at the moment but a lack of cold nights and generally mild/warm days mean that it will likely be a period of unexceptionally above temperatures for the forseeable.

I'll make mine a guess (for fun, not because I'm hiding my age!) Here's the Heathrow stats for June, July and August of said year. Not a summer for the record books but a very average summer in many ways. Each month had a heatwave of at least 32C somewhere in the UK, there were some big storms at times such as June 26th, July 3rd/4th and August 9th. A summer I'd be very pleased with as it was a very un-extreme summer.

WYorksWeather I was just referring to the cold blob to our NE at days 8-10 that if that did happen would threaten at least relatively cooler conditions. If you have cool uppers and a NE flow it’s gonna be quite cool. But given it’s a long way out as stated I don’t expect it to happen.

Uncertainty It’s a long way out so I don’t expect it to come off but the GFS and the ECM around the 13th-15th looking like a cold pattern once again for more Scandinavian areas, a winter that’s never left them it seems. Even here it would threaten a return to colder than average conditions… I don’t expect it to happen but those type of weather patterns are most likely in April and May.

The moans thread has turned into riddles

June 2005, a month of great contrast. The C.E.T. up to the 14th was only 13.1C. There were some pretty cool charts. Spectacular flip in the second half. The 15th to 30th averaged 18.2C with a remarkable daily C.E.T. of 23.2C on the 19th. There was an unofficial high of 34.4C this day but the accepted high was only 32.8C. I think June 2005 is one of the months that got the largest increase to the overall C.E.T. when the dataseries was updated in 2022.

Looks like the divergence between the ECM and the GFS 12z starts on the Saturday the 11th. The GFS has a more robust area of high pressure up into the Norwegian Sea and also a more defined trough to our east. By Monday the 13th the GFS 12z is exploring the idea of a rather flabby Scandinavian high with winds turning to the east, a common pattern at this time of year but one that makes eastern coastal residens shudder! Meanwheile the ECM is sticking with the idea of a general breakdown from the west . Dare I say both look like they lead to potentially not the best conditions. Of course they're very different options so it's not worth worrying about whether they verify but the trend for a shake up of the high around the 13th still looks to be there, but how it comes off is uncertain. Expect many different outcomes to be toyed with. The ECM ensemble does show that the idea of the Atlantic coming in isn't without some support. Because it is a mean though, I could see how any one of the potential outcomes comes off. Perhaps high pressure to our north-east will nose in and turn the winds to the east, perhaps low pressure will come in off the Atlantic or berhaps it could stall and lead to some potentiall warmer conditions. Either way, nothing exceptional on the horizon and some lovely days to come shortly after some less bad than expected ones already. Enjoy the Bank Holiday everyone.

damianslaw A very typical set-up for the 21st century. Not the topic for it here but you have to wonder if the extra moisture in the warmer air is disproportionately affecting the nights more than the days during the warmer half of the year.

August 1927 somewhat reminds me of August 2004 for some reason. The latter had more of a influence of high pressure in the first half but the overall pattern wasn't too dissimilar with high pressure over Scandinavia and a slack southerly flow. Both then transitioned into a spell of frequent low pressure domination with northern blocking. Both were exceptionally thundery. August 1927 was a lot cooler but actually the Met Office reports of the time report it as a slightly warmer than average month for the time. I did a crude estimate of what the same synoptics would produce nowadays almost 100 years later and it would probably be in the low 17s.

There’s something beautiful about this thread— people moaning about people moaning in the dedicated space for moaning

Who knew a simple high could cause so much worry . I suppose when you don’t have ridges for a while you become over-sensitised to them! The outlook looks fine bar some unforeseen weather front or something. I think it’s a shame if anyone would approach the weather hobby as a point scoring thing and search for things to go wrong. The behaviour gets pointed out always but I find a lot of the ones who point it out usually do the same behaviour anyway. Unfortunately the weather does what it pleases to the chagrin of us all. But never mind all that, we’ll have high pressure for about 4 whole days at the very least. I thought that’s what people were excited about.

If anything the GFS 0z looked to be further gradual improvements. It’s no heatwave but there looks to be a nice anticyclone that’ll give nice low 20s weather and should be quite sunny plus the nights will be comfortable and perhaps rather chilly. The 0z has also put back the idea of a breakdown a couple of days. Could be signs the high may last a little longer than it did yesterday. That being said, the ECM does show perhaps a little pressure weakening around the 13th as does the ensemble. To me it looks similarly as it has down for a while, a nice spell of weather for a couple of days then perhaps turning unsettled again around the 13th.

Ah, the 19th century. When even some of the Mays could wallop our winters today.

B87 I dunno, looks pretty green to me. Even though there's no doubt it was behind that year, very mild springs in recent times have warped our sense of normal leaf, particularly the young (me!).

B87 Some but even then there was a nice spring feel. This is an image taken on Primrose Hill on 6 May 2013. I remember this day well actually. It was a warm and sunny day with temperatures around the 20C mark. One of the only warm days like it during that month . That image is how parts looked this year about a month earlier than that. These were taken on the 12th and growth was established.

I feel like years like 1986 where grey and unpleasant weather lasted well into the spring, while they probably did get taxing, they at least had cold and snow to make it enjoyable (for some of us). If 2024 had been similarly unsettled but an inverted temperature profile, aka cold and snowy throughout, at least it would have been fun and worth it. I feel like persistently mild and dull zaps the life out of everything. Everything gets grown prematurely, before you know it the blossom has blown away by early April and the daffodils look sad and then it's just muted greens by May. At least in a delayed spring I feel like you can enjoy things eventually. I don't remember spring 2013 feeling so bland. April 2013 even had a very warm and sunny spell. April 2024 just had a very warm sector within a low pressure system lmao.

Still a build of high pressure shown for the 7th on the 0z though a little cooler than the previous run. The high is oriented a little differently, the uppers are cooler and there is slight less thickness, though still I imagine would get the temperatures into the upper teens/low twenties in favoured spots, particularly come Friday. Some pretty cool nights with suggested minima around 5-6C in parts. After that, still a trend to introduce lower pressure by the 12th. You can't get nicer weather than that to be honest. Fair, sunny weather by day with temperatures in the upper teens/low twenties and cool single digit minima. The perfect balance between sunny and comfortable. The model is experimenting with slightly different orientations of high pressure, some warmer some a bit cooler. The previous run was quite warm and showed potentially our first 25C by about the 10th. This one is a cooler example.

Scorcher I don't know if you saw but in the thread about May 1833 and the polar (no pun intended) opposite spring of 1837, but the C.E.T. station was actually solely being recorded in London at that time. Now of course London was far less of a UHI producer back then, but the locale suggests that while it's still an exceptional month, if it had data from further north like now, it may have indeed been a tad cooler than 15.1C. Maybe at least. May 1992 apparently had a warmer mean than 15.1C in London but that's of course by the time London was built up. Interesting nonetheless.

Alderc 2.0 To be fair, last ECM I saw showed that low pressure was increasingly breaking down high pressure by about the 12th and this is the third GFS run in a row to break down the high around that time. I’m not convinced we’re into a sustained dry spell or anything but it could at least be a first bite of the cherry type affair.

Latest GFS run shows a slightly different but basically similar premise. After the shallow low on the 6th clears high pressure builds in by the 7th, though the remnants + weaker pressure could mean the risk of cloudier and showery weather in the southeast if this doesn’t correct southward. Then looking warm and dry from the 8th through til the 10th at least. The 10th looks particularly warm with a ridge over the country and 10C uppers in the south. I wouldn’t rule out mid-20s if that came off. Still, the trend is more things to turn more unsettled by day ten. The solution isn’t miles away from what the ECM showed earlier, the ridge breaking down with Atlantic low pressure taking over, though temperatures would still remain above average, most notably so by night. Like @WYorksWeathersaid, nothing unusual coming in terms of absolute max, but high minima and persistently rather warm days is all it takes to get the ball rolling on a warm May. All in all, still somewhat of a signal at this time that unsettled weather may shortly return, so we may not staring at a significant pattern change to warm and dry weather but it will be a pleasant and welcomed interlude for many. The models could always however be underestimating the strength of the block though and by day ten there does seem to be a strong Azores high. Not a terrible outlook at all.

raz.org.rain I feel like sunspots would have been more useful in a world where we weren't facing AGW, but any effect they have easily gets overridden. If I put a droplet of water into a giant bowl of flour I'm not going to make dough.

raz.org.rain This year has played out uncannily similar to 1998 though just in different times. You never get an exact match. It's why I eye-roll people who search for exact matches of months in terms of C.E.T. It's more about the general pattern, even if they occur maybe in a different order.

Only putting this here as I don't know where else to put it, so feel free to move this to a more appropriate place like in the CC section, but back in March the topic of rain days came up in order to determine whether if it's getting wetter or if the rain is getting more intense but rain days are increasing. It was allowed here then. Thanks to the Starlings Roost Weather website I'm able to see a graph of UK wide rain days (and other data) all the way back into the 19th century. Starting with annual rain days. We can see a very high frequency of rain days from the begininning of the graph until about 1931 which then it decreased. From the 1960s through until the 1990s there was a sharp reduction with somewhat of a return, albeit less so, to the values experienced in the first half of the 20th century. Compared to the mid-20th century there are more rain days now but not to an unprecedented level, at least since 1891. But annual can hide seasonal variation, so let's take a look at the trend for rain days in the winter. Again, we see a decline in the number of winter rain days in the mid-20th century and this makes sense as weather patterns were more blocked in the winter leading to more successful thwarting of Atlantic fronts. There does, unsurprisingly, seem to be a trend back up in the 21st century and quite sharply so, suggesting that rain days in the winter are becoming more common and with more moisture in the atmosphere this does follow the idea of our winters become wetter and stormier but not just by intensity, but in frequency. Now we'll look at the summer. Now there is a theory that UK summers will get drier. Let's see if the rain days data shows this. It actually shows a sharp decline already took place in cooler times but has now moderated back to a higher frequency though only sort of back to a regular level. Whether this was natural variation in the mid to late 20th century or a sign of things to come, who knows. But it shows that at least currently, summer rain days appear to be static. Here are spring and autumn too. Spring rain days appeared to drastically fall in the mid-20th century among other seasons but then increased in the late 20th century and have actually decreased again. Of all the seasons, spring seems to have the most of a sinewave pattern and whether we go back up again or not is unknown. Spring is a bit of a wild card as March could easily see a similar trend to the rest of the winter but by May blocking could be more intense. Autumn is the most straightforward however, with there being not much of a trend in terms of rain days, perhaps slightly upward. Again, October and November are more likely to be affected by the increasing zonal pattern whereas September is more of a wildcard. Winters look the most clear to me with summers a little less so. We're only about 30 years into this new phase of climat e so trends are very much in their infancy and will have to be monitered very closely. However, putting it all together, I would say at the moment there isn't much evidence to suggest our rain days are becoming more infrequent, at least yet. It's interesting looking at the sections of the graphs that cover the first 30 years of the 20th century, a time when the UK climate was warming quite fast compared to the 19th century, though this was mostly felt in the winter. It's telling to me how both times the climate has begun to warm, rain days and rainfall have increased. We know warmer air holds more moisture. Now larger scale patterns could change this, but provided we stay Atlantic dominated, I say keep those umbrellas at the ready.