Several heat domes are currently raging in the Northern Hemisphere. While their presence is usual, their intensity is less so. Here's why.
Record temperatures from the USA to China
Looking at our atmosphere, three heat domes have formed aloft:
- In North America, it particularly affects the southwestern United States. Well encamped over this region for more than two weeks, it is helping to keep temperatures above 43.3 degrees in Phoenix, Arizona.
- Another dome is affecting southern Europe and northern Africa. The countries most affected are Spain, Italy, Morocco and Algeria. Rome broke an all-time heat record: the thermometer registered 42.9 degrees in the Italian capital's city center on Tuesday July 18.
- The last dome is located over East Asia. Here again, it made history in a small town in northwest China. Sanbao set an absolute national record on July 16. The new mark now stands at 52.2 degrees. The station is fairly recent, however, so it doesn't date back very far.
Fig. 1; Source: GFS
Please note: although these domes affect several countries, the heat is not generalized to all these continents.
A particular dynamic
It's summer in the Northern Hemisphere, so there's nothing unusual about it being hot in these regions. The ridges responsible for these heat domes are a normal feature of our atmosphere, but it's their intensity that is surprising.
Another factor contributing to the phenomenon is the length of these heat episodes. The south-western United States, for example, has been experiencing excessively hot temperatures for several weeks. Under the dome, the atmosphere stagnates, allowing the heat to gain in intensity.
