Hard Frosts

Director of the Meteorological Office of Russia Roman Wilfand on atypical weather

The weather of the first two weeks of the new year was very unusual. When I say "very unusual" I mean it. On the European territory of Russia was observed very high anomalous plus temperatures. The temperature surpasses usual figures, which are indicative of this time of year, by 8-12 degrees. If there is one day like that, it is a typical phenomenon. But when for two weeks we have the same temperature it is unusual. Considering that December was also very warm, it had a large impact. The temperature diagnostics shows that there has never been such a prolonged warm period. What effect does it have? The River Oka has not yet been frozen. In its lower part, where it flows to the Volga there is already ice, but in the upper and middle reaches of the river we observe regular flowing. Neva has not been frozen, it is not covered with snow and it is a very unusual phenomenon. As a result of the past one hundred fifty years of instrumental observations, the statistics have established that the average date of the Neva's glaciation is November, 7. Last year the Neva was covered with snow on December, 5 – a bit later than usually, but it is no problem. Before this year the latest date when Neva became covered with snow was December, 25. Now it is already January 13, the water flow is amazing, like in summer or spring and only slush comes from Lake Ladoga. According to hydrologists, in a week Neva will become covered with light ice. Such phenomenological characteristics as rivers' glaciation are manifestations of a truly unusual weather. Such warm weather is caused by intense and constant movements of cyclones which bring from its Southern borders, via Western Europe a very warm air from the South-West Atlantics and from Mediterranean. These processes took places even before but they never used to be so prolonged. However, our country is vast and I have been speaking only by its European part while the situation in the Asiatic part of Russia is very different. The circulation in the Asiatic part of Russia, the so-called second synoptic region (the Western part is called the first synoptical region) is in no way related to the first synoptical region and their mechanisms are disconnected. The temperature there depends on pulsations of the Mongolian or so-called Siberian anticyclone. In the first days and weeks of January this anticyclone was very active, its pressure was higher than 1000 millibar which leads to freezing of the underlying layer, intense cooling of the air. Temperatures in Yakutia and Magadansk reached from 55 to 60 degrees below zero Celsius. Today in Yakutia it is minus 57. It is very low. In Magadansk the temperature is also very low. Thus, these two regions are not very connected between each other. The weather in the European part is dictated by cyclones coming from the West, South West and North West, while the weather in the East is connected with dynamics and pulsations of the Siberian anticyclone, increases and decreases in the layer of inversion or unusual temperature distribution when a temperature grows in connection with altitude and when the lowest temperature is next to the surface.