Jeff Masters Hurricane Blog

104°F? A Continental heat wave heads for England » Yale Climate Connections

Relentless heat that’s been plaguing much of Europe this summer is now making a run for the United Kingdom, which appears likely to experience the hottest temperatures in its long history of record keeping on or around Tuesday, July 19.

On Friday, July 15, the U.K. Met Office issued its first-ever “Red Extreme” heat warning, accompanied by the first forecast ever issued by the agency for any part of the United Kingdom of temperatures reaching 40 degrees Celsius (104 degrees Fahrenheit). The nation’s all-time record high is 38.7°C (101.7°F), recorded on July 25, 2019, at the Cambridge Botanic Garden.

In London, Friday’s officially predicted high of 37°C (98.6°F) on Tuesday would approach the city’s all-time high of 38.1°C (100.6°F), set at Kew Gardens on August 10 during Europe’s catastrophic heat wave of 2003.

Read: Heat waves and climate change: Is there a connection?

Meteorologist Simon Lee, co-editor of the Royal Meteorological Society’s magazine Weather, tweeted a compelling comparison of a hypothetical weathercast in 2050 and an actual one for next week.

“I don’t think you can interpret this as climate change occurring ‘faster than anticipated,’” Lee added. “Climate models have shown that 40 C is possible in the UK in the current climate, just very rare. My point is that what is coming on Tuesday gives an insight into the future. In the present climate, 40 C represents a new extreme, which is becoming more likely due to climate change.”

Perhaps even more shockingly, the official forecast for the overnight low in London on Monday night is 25°C (77°F). The warmest daily minimum ever reliably observed in the entire United Kingdom is 23.9°C (75.0°F), recorded in Brighton on August 3, 1990. If London does stay above 25°C early Tuesday, that could easily become the 24-hour minimum for the day, as no dramatic cooling is predicted before at least midnight Tuesday night.

“Nights are also likely to be exceptionally warm, especially in urban areas. This is likely to lead to widespread impacts on people and infrastructure,” warned Met Office chief meteorologist Paul Gunderson in a press release.

The forecast also includes lows of 20°C (68°F) on both Sunday and Tuesday nights, which would give buildings and people little chance to cool down with predicted highs on Sunday, Monday, and Tuesday of 29°C, 35°C, and 37°C (84°F, 95°F, and 99°F).

Only around 3% of residential homes in the U.K. have air conditioning, and many public facilities (including the London Underground) are not air conditioned thoroughly or at all.

While the peak of this heat wave will be limited to Monday and Tuesday — reducing the risk of a nightmarish death toll at least slightly — unusually stifling conditions will afflict much of the U.K. for much of the week. All told, London could experience more than 80 consecutive hours above 20°C between Sunday morning and Wednesday evening.

For context, the average daily high and low in London in mid-July are around 24°C and 14°C (75°F and 57°F), respectively.

Wildfires rage as scorching heat sprawls across much of Europe this month

The prospect of a brief but intense encounter with 40°C heat in London pales next to the torrid temperatures being recorded for days on end across much of western and southern Europe. The epicenter of this month’s protracted heat wave (which follows a similar event in June) has been in France, Spain, and Portugal, where several cities have set monthly and all-time heat records, including on Friday.

The preliminary high of 47.0°C (116.6°F) in Pinhão, Portugal, on July 14 will be a new national record for July if confirmed, noted weather records expert Maximiliano Herrera. Also on July 14, the tiny nation of Andorra tied its all-time monthly record with 38°C (100°F) in Borda Vidal.

One death has already been reported from wildfire in Portugal, which is especially prone to devastating fires during its dry, hot summers. According to The Guardian, more than 800 people have been evacuated from fires in Portugal, and in southwest France, more than 10,000 people were forced from campgrounds on Wednesday and Thursday.

The stage was set for this summer’s intense European heat by relatively dry conditions in late summer and spring, combined with unusually early springtime warmth that helped hasten evaporation from already dry soils. Similar conditions preceded Europe’s horrific 2003 heat wave, which peaked in early August. Multiple studies found that the heat-induced death toll across Europe that summer was in the tens of thousands, and one study estimated that there were more than 70,000 “excess deaths,” which are deaths that would not otherwise have immediately occurred. Older residents in buildings that lacked air conditioning were especially hard hit.

Meanwhile, back in the torrid United States …

A grinding summer of heat continues to beset much of the United States. Although none of the contiguous U.S. states had their hottest June on record, every state in the southern half of the nation was at least somewhat warmer than average, and four states — Texas, Louisiana, Missisppi, and Florida — had a top-10-hottest June.

Likewise, the calling card of summer 2022 thus far hasn’t been a large number of all-time highs (which exceed 110-120°F in many locations), but rather the deflating persistence of above-average heat for days on end, especially in the Southern and Central Plains. Even without reaching the almost cartoonish highs projected by some computer models (including the GFS, which has a known bias toward unrealistically high summer readings in this region, especially more than 3-4 days out), the heat is wearing on millions of residents. Among the cities with longstanding weather records that have notched their warmest first half of summer (based on June 1–July 14): 

Austin, Texas:  88.7°F (old record 87.6°F in 2011)
Houston, Texas:  87.3°F (old record 86.5°F in 2011)
San Antonio, Texas:  88.6°F (old record 87.2°F in 2009)

Figure 1. Drought conditions deteriorated rapidly across Oklahoma from June 28 (left) to July 12 (right). (Image credit: U.S. Drought Monitor)

Making matters worse, a flash droughtdefined as rapid onset or intensification of drought, set in motion by lower-than-normal rates of precipitation and accompanied by abnormally high temperatures – has erupted in the last several weeks. Rainfall averaged across Oklahoma was the lowest for any June 14-July 13 period on record (0.62 inches, versus an average of 3.67 inches), even including the infamous Dust Bowl of the 1930s. Over the two weeks ending on July 12, the U.S. Drought Monitor reported that abnormally dry conditions in Oklahoma leapt from covering 46% to 100% of the state, while moderate to severe drought jumped from 31% to 63%.

“With the rapidly developing situation, without relief from the heat or precipitation, drought will continue to intensify rapidly,” warned Brian Fuchs of the National Drought Mitigation Center in this week’s U.S. Drought Monitor.

Jeff Masters contributed to this post.

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