MAIN WEATHER AND CLIMATE TRAITS IN THE NORTHEN HEMISPHERE AS OF MAY 2021

Air Temperature

This May in Russia was extremely warm for the second year in succession. A year ago, the air temperature monthly-averaged over the entire territory of the country reached the absolute maximum for 130 years of regular meteorological observations. This year, the value was almost half a degree lower than the absolute maximum, but still higher than the normal one in most of the country. The only exceptions where this month was colder than usual were certain districts of the Pskov Region, and the vast areas around Baikal and further eastwards: the Trans-Baikal Territory, the Amur Region, parts of the Khabarovsk Territory, and Sakhalin. The highest positive anomalies (+4…6° and above) were observed in the areas from the Volga Region to the Pacific Ocean, including the Arctic region. This May was the warmest in the history of meteorological observations since 1891 in the Volga Region, and the second warmest in the Urals where the record-breaking result of the previous May remained unbeaten. The average air temperature in Siberia and in the north of the Far East entered the Top Ten of the highest values in the meteorological chronicle.
The weather in most of Russia was abnormally hot throughout the month. Sub-normal air temperature averages were only observed in the ETR in the first and third decades, and in the Trans-Baikal Territory, the Amur Region, Sakhalin and the south of Khabarovsk Territory in the third decade. In contrast, numerous daily temperature maxima were recorded in the Middle and South Urals, in the south of Western Siberia, on the Upper and Middle Volga, in the Russian North, in Central Russia, in the north-west and south of the country, in Yakutia and Chukotka, – for several days in a row sometimes. On the other hand, cold weather with frosts repeatedly returned to Central Russia and the south of the Urals in the first decade, to the south of Siberia, in the second, and to the north-west, in the third decade.

MAIN WEATHER AND CLIMATE TRAITS IN THE NORTHEN HEMISPHERE AS OF APRIL 2021
 
Air Temperature
 
The first two decades of April were abnormally warm in the ETR. During the second one, the decade-averaged temperatures exceeded their normal values by 4-6°. In the North Caucasus, the air warmed up to +30° sometimes. New daily temperature maxima were recorded in Central Russia, as well as the Russian North where the daily-averaged temperature never dropped below the normal value on any of the twenty days. Yet, the weather became cold in the third decade: its average temperatures everywhere in the ETR save for the Arctic territories were subnormal, down to 2-3 or more degrees below the normal values in some places. Even in the Volgograd and Rostov Regions in the south, April ended up with occasional night frosts.
In the Urals and in Siberia, anomalous warmth with the normal average monthly figures exceeded by 4-7° and more was steadily observed in the north only, whereas in the southern areas, the weather was more volatile. For example, the record-breaking warmth in the Irkutsk Region alternated with the record-breaking cold in Altai and in the south of Western Siberia.
Such volatility was even more noticeable in the Far East. While the temperature anomalies from Taimyr to Chukotka reached -2…-5° in the first decade, the weather in this area became as much as 2-7° warmer than usual in the second and third decades. Unprecedented warmth at this time came to the northern regions of Yakutia and to Chukotka. There, new maxima of daily temperatures were recorded in bulk. The temperature background in the rest territory of the Far East was more stable during the month: in each decade, the average temperature fluctuated around its normal value and did not exhibit large anomalies. The only exceptions were Kamchatka and Primorye where the weather was 2-3° warmer than usual in the first decade, and the Amur Region or south regions of the Khabarovsk Territory where the anomalies turned out to be negative (-1…-3°) in the second decade.