The main weather and climate features of the northern hemisphere in October 2017

Air Temperature.

The first decade of October in the most part of Russia became an abnormally cold. At the beginning of the month the colds to -5°came to the south areas of Central Federal District (Lipetsk, Tambov, Orel, Belgorod and Voronezh regions). The same situation took place in the Low Volga area and in Stavropol district. Heavier colds were observed in the South Urals, in Yakutia frosts reached -20°. In some places of Ural, Siberia and Far East Federal districts it was colder than usual by 2° and more over the decade at the average.

Everything was changed in the second decade. Now from the west border to Urals, and in the Arctic territory up to Chukotka the warmth dominated. The average decade air temperature anomalies in some places exceeded +4…+6°. In the north of Yakutia, Kolyma, Chukotka and Arctic islands the new record air temperature maximums were registered. Only south areas of the Far East, as before, remained in the cold.

In the third decade once again the cold weather returned to the European Territory of Russia (ETR). In the north-west the decade became colder the norm by 2-3°. At the same time, it was, as before, warm behind Urals, including the south of the Far East. Although the frosts in Evenki and Yakutia were strengthened up to -30°, the average decade air temperatures exceeded the norms by 4-7°. In the south of Siberia and Khabarovsk district the air temperature daily maximums were registered.

Such alternation of warmth and cold caused the proximity to the norm of average monthly air temperature in the federal districts, as well as in Russia in general. In the most part of the country in happened with positive anomalies, in the south of the Far East and the West Siberia – with negative ones. Only in the Arctic territory (north-east of ETR, north of Urals and Siberia, as well as in the north areas of the Far East) the month became noticeably warmer than the usual (by 2-6°).

In the most part of East and South-East Asia the temperature conditions in October became close to the norm. Only in some places in the south of Japan and China they exceeded it approximately by 2°. In Japan the air was heated up to +30° and the new temperature maximums were registered.

October was warm in India and Pakistan. In some places, especially in Pakistan, the average monthly air temperatures exceeded the norms by 2-3°.

Air temperature reached especially high values in the Middle East and in Central Asia. Here the norms were exceeded by 2-4°. In republics of Central Asia the air was heated up to +30° and more even in the end of the month. 
In the most part of the North Africa the average monthly air temperatures corresponded to the norms. Only in the north (Algeria, Tunisia, Libya) the temperature became colder than usual, in the north-west – warmer (approximately by 2° and more). In Morocco it was hotter than +33°.

In all Europe in October it was abnormally warm weather. But if in the east the norm exceeding was insignificant, as a rule, less than 1°, in the centre and west – in some places it reached 3-4° and more. Many countries have the new temperature maximums. In Scandinavia the air was heated higher than +15°, in the centre and west of the continent – higher than 20-25°, in the south of Spain – up to +35°. In Portugal and south-west of Spain the heat and absence of the precipitations caused the numerous fires.

In the North America continent the abnormally warmth dominated in the east of USA. Here the norms were exceeded by 2-4°. The last October has been the warmest one in north-east of the country since 1895. Another heat anomalies focus was situated in the west of USA in California and in the north of Mexico. Here the temperature norms were exceeded by 2-4°. At the same time west of USA (territory to the west from 100° of west longitude and to Pacific coast) was in the conditions of the abnormally cold weather (anomalies to -2…-4°). This cold was spread also to the west provinces of Canada, whereas in the east and north of the country it was noticeably warmer than usual – by 2-5°. At the average, in USA and Canada the average monthly air temperature exceeded the norm approximately by 1.0-1.5°.

The average monthly air temperature in Arctic closes the first ten of the highest values in the range. Temperature norm was exceeded approximately by 3°. The last October, which is considered as the warmest one on the record in Arctic, was warmer the norm almost by 5°. As it known, in September in the Arctic basin the ice thinning minimum was reached during the season. However, in some areas (Chukotka sea, Beaufort sea) the ice melting was continuing. Only in October the Arctic-wide ice-thickness began.

The average October air temperature in Northern Hemisphere has a rank 3-5 among the highest values (together with 1995 and 2010). Only Octobers of 2015 and 2016 were warmer. Except particulars of average monthly air temperature anomalies allocation in the Northern Hemisphere, mentioned above, there are negative anomalies in the equatorial part of Pacific ocean, i.e. in the so called zone of El-Niño fixation.

In Moscow the average monthly air temperature is +5.0, it corresponds to the norm.

Ocean Surface Temperature.

The sea surface average temperature anomalies (SST) of Pacific ocean were kept at the level of September, anomalies of the Atlantic ocean – became less by 0.1°. The main peculiar of SST anomalies in the Pacific ocean is a continuing increasing of area with negative anomalies in the equatorial latitudes. They also rose by the absolute value. The average anomaly of El-Niño zone in October was -0.5°, i.e. reached the boundary level between neutral phase and La-Niña. For new La-Niña it is necessary the increasing of this anomaly at least by 0.1° and to keep this level not less than three months in succession. Only these conditions can indicate the La-Niña return. For the present one can ascertain that new El-Niño origin, predicted by many model calculations, is being delayed in the present conditions.

Very warm water in October was observed on the Chukotka sea surface and Bering strait and cold one – in the north of Japan and south of Okhotsk seas.

In the Atlantic ocean the SST anomalies up to 2° and more took place along the east coast of North America, also in Norway, Greenland and Barents seas.


Precipitation.

European territory of Russia in October was inundated with rains and powdered with snow. Everywhere, except Russian North, the atmosphere precipitations set the norm and more. Besides, federate entities, where the precipitations monthly sums exceeded the norms in 1.5-2.0 times, became noticeably more than those with the registered norm. In Kaliningrad, Smolensk, Tver, Bryansk, Belgorod, Saratov regions, Krasnodar district, Karelia and Adygei republics, Karachaevo - Cherkess republic the norm was exceeded in 2 times. In the end of the month the rains were changed by the snow and sleet. In the Central Russia the fresh snow depth exceeded 10-15 cm. But soon this snow was melted. Snow fell even in Crimea. Its depth in the mountain passes reached 30-40 cm.

In the Urals and to the east the precipitations situation was more tranquil. Here the monthly precipitations sums have set the norm, or less the norm. The last is related to the south areas of Siberia and the Far East. So, in Altai, Khakassia, Buryat republics, Irkutsk regions, Transbaikalia, Khabarovsk and Primorye districts, Jewish Autonomous republic it was only half of the monthly precipitations norm. In September the snow in Siberia was a rare phenomenon, it fell and melted swiftly, but in October the snow cover noticeably extended its boundaries, including agricultural areas, making the constant snow blanket. In the south of Primorye the first snow appeared on 10 of October, and now it is the earliest day of the first snowfall in the region.

Central and east Chinese provinces were inundated with rains. In some places the precipitations norm were exceeded in 2-3 times. A lot of precipitations had north-west areas, in the west of the country it was a few rains. In the south of Japan the norms were exceeded in 2-4 times, in the north they set the norm.

South-East Asia had a lot of rains. In some places the precipitations norm were exceeded in 2-3 times, especially in the north and central areas of Vietnam. Here more than 400 mm of rains have fallen over the several days. Sequenced floods and landslides caused hundreds of casualties and numerous damages.

In India the rains fell only in the south of the country, where the summer monsoon continued yet, and all other territory, like neighbouring Pakistan, have not got the precipitations at all.

It was absence of precipitations in the Middle East. Only in Transcaucasia there were heavy rains, which caused the mountains mud flows.

In the Central Asia the dry south (Afghanistan, Tajikistan, Kirgizia, south territories of Uzbekistan and Turkmenistan) opposed to the inundated Kazakhstan, north areas of Uzbekistan and Turkmenistan. In the north the precipitations norm prevailed, with 2-3 times more the norm, but in the south it was less than half of the norm, with full precipitations absence in some places.
In North Africa rains fell only along Mediterranean coast and in some places to the south from Sahara, their abundance was felt especially in some places of Atlantic coast.

One can divide into three categories the Eastern, Central and West Europe by the October precipitations quantity. The first (Eastern Europe) has got substantially less the precipitations norm. In Ukraine, Moldova, Romania, Bulgaria the precipitations norms were exceeded in 2-4 times. In Kishinev the monthly precipitations norm fell over the day. The second one is – precipitations norm and slightly more. This is Germany, Austria, Czech, south areas of Scandinavia. The third one is – less the norm of precipitations (France, Spain, Portugal and Italy). Here are areas with absence of rains during all month.

In a most part of Canada, except northern territories, in the east and central states of USA it was a lot of precipitations in October. In Nebraska, Illinois, Iowa, Wisconsin, Indiana, Michigan, Ohio, Tennessee, Kentucky, monthly precipitations sums exceeded the norm in 2-3 times. In Michigan, Wisconsin, Minnesota the monthly precipitations sums are included in the first five of the highest values since 1895. The norms are exceeded approximately in 1.5 times in Canadian provinces Quebec, Ontario and Saskatchewan. Record-braking snowfall fell in the British Columbia province. Over the two days 23 and 24 October snow covered the ground with the height up to 55 cm. In was not seen of such snowfall here in October.

West areas of USA and Canada suffered from the deficiency of rains, especially American states of California, Nevada, Arizona and New-Mexico. Here is was absence of rains, which caused in California to heaviest fires.

Heavy rains fell in Central America. In Nicaragua, Honduras, Salvador, Columbia they caused floods and landslides with hundreds of casualties.

In Moscow over the month it was 93mm of precipitations, that is 158% of the norm. The annually precipitations norm in the capital was accomplished by the end of October. The first snow in Moscow appeared on 22 of October, on 28 in the Moscow vicinities the temporary snow cover was formed with the height from 1 to 8 cm.