This week has brought warmth and sunshine. Today, saw 25+C forecast and 27.5C has been recorded at London Heathrow (81.5F). There has been rain and thunderstorms in the forecast too, for today and tomorrow, but the Tuesday chat is about the warmth.
Netweather Radar showing rain and (updated) Tuesday temps, List of highest hourly temps 17th May and Will it Thunder?
The UK media headlines are hyping up the HEAT and RED map, "HOTTEST day of the year" (so far, it’s only May), "North African tropical blast", "Britain to roast in sweltering 28C heatwave". It’s not a Heatwave, it's one hot day, Wednesday is also very warm for SE Britain but then maybe 23C as a maximum for London for the rest of the working week. A true Heatwave has impacts. India is having a heatwave and people are dying. It’s affecting crops, such as wheat, that are usually exported and wheat supply is already down due to the war in Ukraine. Spain now has a heightened wildfire risk as the dry, hot weather continues.
That may seem almost grumpy point of view when it is a lovely day outside with warmth and sunshine (also rain from the west) but we wouldn’t scream “it’s a drought” if it didn’t rain for two days and things had been okay otherwise. Our climate is changing and how we communicate matters. For an official UK heatwave, there are thresholds to meet for 3 consecutive days. For London and surrounding counties, it is 28C.
Tuesday forecast temperatures from UKV model
The UK has seen over 23C already this May and yesterday Heathrow airport reached 23.1C (73F). North Wales, Cheshire and Yorkshire all saw over 22C. Today over 26C is possible with more of the UK feeling very warm in fine sunshine and humid southerly flow. The UK record for May is 32.8C
This heat has moved up from north Africa, the desert rather than the tropics. It continues to feed up over Spain and through France, heating under sunny skies by day. Temperatures in France today are forecast to reach 28 to 30C with a Thunderstorm warning in the NW. Spain has a small area warning for high temperatures, up to 36C in Zaragoza and 38C in the south later this week.
Temperatures in mainland western Europe at 30C or above
For France, the ongoing warmth “makes it very likely that this month of May will be the hottest ever observed”
For the UK, we do often see great variations with our weather. May especially can bring cold weather early in the month with frost, even wintry flurries giving the impression that winter will never leave. However, once the sunshine gets to work there is strong warmth and with more daylight hours the temperatures lift. With the right wind direction and a feed of warm air we can see these very warm episodes.
Today looks to be the peak of it this week for the UK, although still warm on Wednesday. The rain from the west, a cold front does affect the temperatures, clearing out of the warm, humid feed but it does start up again tomorrow.
In the ongoing southerly feed and sunshine parts of Britain will again have warmth and temperatures in the high teens, low twenties. The southerly breeze will freshen through Ireland, so lee effects could result in a few northern higher temperatures on Wednesday.
During Wednesday night, a plume of very warm, humid air is forecast to push north, clipping SE England with the risk of thunderstorms being highlighted. After that, the air isn’t as warm for the rest of this week although any sunshine will still bring local warmth. Early next week could see UK temperatures nudging up again from the teens back into the 20s Celsius.