It looks like the last days of July and early August will bring Europe's strongest heatwave in the summer of 2021. Temperatures are expected to rise above 40 ° C in some areas, while Greece may rise to 45 ° C on weekends. This will significantly increase the threat of forest fires in the Mediterranean region and the Balkan Peninsula.
July brought intense heat mainly to the southern and southeastern regions of the European continent, while there were no significant heat waves in the west. The hottest temperatures were observed over the Mediterranean, the Balkan Peninsula and Turkey, at times exceeding 40 ° C. Recently, however, the heatwave has spread to the generally cooler UK and Ireland, with temperatures below 30 degrees Celsius last week.
But this week, an uncharacteristic picture is emerging over Europe, which is prone to extremely high temperatures. The remainder of July, as well as the first days of August, which ends the summer season, will bring the most intense heatwave of 2021.
The reason for the upcoming extreme heat this summer is the new High strengthening blocking from the Mediterranean region to the Balkan Peninsula. The heat will be extreme and will persist for at least a week, and possibly more in the south of the country.
While on the north side of the expanding ridge, a massive cloud of Saharan dust is advancing into central Europe.
Peak temperatures are expected to exceed 40 ° C, with parts of the southern Balkan Peninsula, as well as Italy and other parts of the south-central Mediterranean, possibly even reaching 45 ° C.
Temperature data in the lowest parts of the atmosphere over the next 10 days show that significantly warmer than usual air mass will rapidly spread from the Mediterranean to the Balkan Peninsula, where temperatures are expected to be almost 10 ° C above average.
Parts of Italy, Serbia, North Macedonia, Albania, Romania, Bulgaria and Greece are ready to bake from extreme dry heat. High-resolution models provide clear predictions that agree well with peak daytime temperatures approaching the mid-1940s on the hottest days.
The air mass will remain fairly dry during this heatwave, which should also further increase the potential for wildfires in southern Europe, where drought is most severe. And devastating wildfires are already continuing in Sardinia, Italy this week.
This drier than usual weather is likely to continue in the south, so conditions are expected to get worse. Drought and wildfires are other side effects of significant heatwave, while heatstroke remains the worst.
Due to a fairly steady warming in recent weeks, sea surface temperatures have also increased. Even significantly in some parts of Europe. In the Baltic region, it remains extremely high, and the water temperature exceeds the norm by more than 6 ° C. Towards autumn, the season of water tornadoes may begin there.
The waters of the Atlantic Ocean around Great Britain and Ireland also remain very warm. About 2-4 ° C above normal for the end of July, which is quite impressive given the lack of significant heat waves over Western Europe so far this summer.
However, the greatest concern is the water temperature in the Mediterranean. In principle, throughout the Mediterranean region, sea temperatures are well above average due to the constant intense heat waves and very high temperatures this year.
This summer, the temperatures of both the sea and the lakes have become very warm. In many parts of the Mediterranean Sea, sea temperatures are almost +3 ° C above the long-term average.
It should be remembered that very warm seas are a major source of high humidity, which is directly reflected in the highest dew points and high or extreme instability when it comes to severe thunderstorms.
Just this Monday, very high humidity contributed to devastating hail near Parma, Italy, where an astonishing number of cars were literally destroyed by stuck in traffic jams on the Milan-Bologna highway.
When summer comes to an end in Europe, the seas tend to be the warmest. This results in very high dew points that often lead to extreme flooding in eastern Iberia, southern France, along the southern Alps, Italy and the western Balkan Peninsula.
Keep this in mind as this could become a potential threat over the next few months as we enter progressive fall models and frontal systems.
The rather typical combination of deep trough / low current over the North Atlantic and Western Europe against a blocking high current in the east results in strong warm advection from deep southern regions of Europe, Mediterranean and North Africa. Earlier this week, it is also combined with the powerful advection of dust clouds from the Sahara Desert.
More stable weather is expected over the next few days in most of Europe. Between the two large-scale systems, southwest winds will gradually return sufficient moisture to the Alps. The next front-facing system is likely to arrive at the end of next weekend. After a period of hot days, violent storms are likely to form.
Under the crest, the heat will rapidly intensify in the coming days, affecting the Mediterranean and the Balkan Peninsula, including at least southern parts of central Europe. And also central Italy. Although temperatures were already in the mid to highs of the 30s this Monday and around the 40s on Tuesday, they will soon surpass 40 ° C. And by the weekend, the temperature will be much higher.
The graph below shows the maximum temperatures observed in central and southern Europe earlier this week, Monday 26 July. From Italy and the southern part of the Balkan Peninsula, there were reports of middle and upper 30 degrees. Cooler conditions persist in Western Europe.
Extremely hot weather persists over Algeria and Tunisia, which already this month reaches about +50 ° C in several days. But this is a really dry heat and a perfectly normal temperature for the region during the height of summer. Due to the lack of moisture, it is slightly easier to carry.
The overall weather pattern over Europe this week is a textbook example of how intense, warm advection brings intense heat. When we see low temperatures in the west (bluish colors) and high (reddish colors) in the east-southeast, we need to know that this will lead to a large increase in temperature.
In the southeastern regions of Europe, a so-called dome of heat with a prolonged period of extreme heat will be established. We use this term when a high pressure area parks over a large part of the continent and remains there for several days.
The thermal dome works like a lid on a saucepan, trapping hot air masses under it. And this feature is often accused of being responsible for prolonged and deadly heat waves around the world.Often a very strong heat wave develops under it with temperatures well above the norm, which casts doubt on some heat records.
A few weeks ago, such a thermal dome brought unprecedented historical heat over the Pacific Northwest of Canada and the United States.
Temperatures will gradually rise in the coming days and are likely to reach high daily highs. In parts of central Europe and the Balkan Peninsula, temperatures will be around 10-15 ° C warmer than normal, which is an extremely hot season for late July.
With the predicted near-surface temperature anomaly, peak afternoon highs should easily reach 40 degrees. It is very likely that after tomorrow, Wednesday, it will be even higher. The hottest places will be the most heat-prone lowlands and valleys.
A scorching heat will set in, we can see highlighted areas where the lowlands usually bring the highest temperatures on summer days. The two graphs below show the highest temperatures on Wednesday and Thursday, July 27 and 29, respectively.
According to the weather model, temperatures in southern Italy, Albania, Greece, North Macedonia, Serbia, Bulgaria, Romania and western Turkey should be between 39 and 43 ° C.
Closer to the weekend, the heatwave is likely to peak and bring the highest temperatures to those same areas. It will be even hotter in the afternoon, but fortunately a little drier, so the heat index will remain the same. The worst combination would be high humidity, but this time it won't.
The highest temperatures will be observed over the southeast of Italy, possibly also over the eastern part of the Po Valley in the north, both on Friday and Saturday. While the most intense heat is expected over the central and southern part of the Balkan Peninsula.
In Greece, North Macedonia, Serbia, eastern Croatia, southern Romania, most of Bulgaria, as well as western Turkey, 40-44 ° C is expected during the daytime.