NH Summer/SH Winter 2020 Discussion Thread

I talk about the NW/SE split in British summer weather quite a bit but this spell we're having at the moment is pretty much a perfect example of what I mean, often it means lows in the North Atlantic giving rain to the north of the UK like we had in July while the SE stays dry, but even without any fronts the SE corner is still much better placed to tap into the hot weather on the continent.



The usual difference in average highs between Bingley and Heathrow in August for example is 4.5C, but it's going to be much bigger than that again this month:

7th: Bingley 25.1, Heathrow 36.4
8th: Bingley 21.9, Heathrow 33.4
9th: Bingley 20.2, Heathrow 33.8

The difference in averages for July is 4.4C but last month the actual difference was 6.7C. I don't know about sunshine but the SE seems to be becoming warmer and drier in summer compared to the rest of the country because the continent is warming up a lot faster than the Atlantic, I bet we'll see that shown up in the 1991-2020 averages.

Going back to this, I found this list of the hottest days of the year since 1900:

www.trevorharley.com/hottest-day-of-each-year-from-1900.html

The hottest temperatures are hotter than they used to be but that's pretty much a given, what's really noticeable about the older years is how it often used to happen in places much further north or west than you'd expect it to now, even in some of the foehn hotspots in Scotland.

From 1958 to 1980 the hottest temperature of the year in Britain (either jointly or outright) happened outside England seven times but it hasn't happened outside England since then at all, and it's pretty hard to imagine it happening now with the way our summers have changed.

All the non-English ones were really cool summers with absolute maxes no higher than 30C, which presumably means no airmasses coming from the S or SE.

All this map means is that Central/Southern europe have hotter averages. If the average goes up 1C, London goes from 23C to 24C while somewhere in France might go from 29C to 30C. London’s not going to have that many more 30C days (sunce such a temperature is still extreme) but the french location is going to have a ton more. A better way to judge the frequency of heatwaves over time would be to look at the proportion of days more than 5C above average or something.

Compare the trends in absolute yearly maximums between uppsala 1980-present, with that of Paris 1980-present.

www.infoclimat.fr/climatologie/globale/uppsala/02458.html

www.infoclimat.fr/climatologie/globale/paris-montsouris/07156.html

Uppsalas absolute maximums remains relatively unchanged, while there's a strong trend in increased extreme maximums for Paris.

Here we go, one of the biggest NW/SE splits I've ever seen.

Another couple of inches of rain today to take us over the 15 inches mark for the month

Paju (NK) border just north of Seoul, already had 21 inches. Can only imagine the rainfall increases even higher as you go into North Korea

Gwangju in the Southwest of Korea reported 26 inches (!!!) of rain this August already. Including two 10 inch events on back to back days.

Just a reminder to some of you: weather is not climate, and trends only since 1961 are weak "evidence".

High today was 89 (32 c) 

So since July 10th, we have had 90 f forecast on 5 days including today. How many have actually hit 90? 1. Yes, fucking 1 of 5 days.

This means there are 10 days>90 so far this year...July 2018 alone had 11.

So a year with the 4th hottest July ever will only end up slightly above average for 90s.