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

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

Air Temperature.


In August the European Territory of Russia kept an abnormally warm weather and sometimes hot one. From Russian North to Northern Caucasus the numerous records of the air temperature maximums have been registered. In South and North-Caucasian Federal Districts temperature repeatedly rose above +40°, in North-West District - +30°, in the last case it is rather seldom at the end of summer. Sometimes a cold Arctic air penetrated to the northern areas and then in Komi republic and Nenets Autonomous region the light frosts and temperature minimums were registered. The average decade air temperature anomalies in ETR exceeded +6°, in some places the average monthly air temperature are above the norm by 3-4°.
In the Urals and West Siberia the most part of the month it was cold weather with the average decade temperature anomalies -3°. In the south of West Siberia in Tyumen, Omsk, Tomsk, Novosibirsk, Kemerovo regions and Altai district the light frosts and new daily temperature minimums were registered.
Northern areas of Far East Federal district all month “bathed” in warmth. In Yakutia and Chukotka the air temperature maximums, as well as absolute ones on the record in August, have been registered. Average decade temperatures were exceeded by 4-5°, and average monthly air temperature became the third highest value on the record, it followed 2014 and 1991. August became warmer than July, it was happened only the third time, in XXI century – for the first time. In the south of Far East the abnormally warm weather of the first half of the month was changed by the fresh and even the cold one in the third decade of the month.
In general, the month became warm for Russia. It is forth-fifth one amongst the warmest months in the range line since 1891. Also, one can classify the summer as an abnormally warm, but insignificantly. Its average temperature exceeded the norm by 1°. After finishing of the three year seasons the average air temperature in Russia concedes only to the same value of the last year. The main contribution to this achievement made Siberia and Far East, where the average air temperature of this period is the highest on the record.
Warm and sometimes hot weather was in East Asia (China, Korea, Japan and Mongolia). In Japan the abnormal heat continued to take lives of the old people. The air, like in July, was heated up to +35°.
In south-east of Asia and India the average air temperatures roughly correspond the norm.
Instead of this, in Middle East and Central Asia it was too hot. In Israel, Syria, Jordan, Uzbekistan and in the south of Kazakhstan the average monthly air temperatures exceeded the norm by 2° and more, in Iran and Azerbaijan – by 3° and more, in Saudi Arabia – by 4-5°.
The same situation is in the north of Africa. In Algeria, Tunisia, Egypt the average monthly air temperature is above the norm by 2-4°. The last month in North Africa became the second hottest one on the record, it followed the August 2015.
Europeans called the last August the “month of African weather”. The new record air temperature maximums on all continent, from France to Belarus, were registered, as well as absolute for August (i.e. for Firenze). This year the “summer peak” in Europe was transferred to August (i.e. it is warmer than July), it is, in general, not so seldom event. So, in XXI century it has already happened for the fifth time. In the most part of the continent the average monthly air temperature is above the norm by 2° and more (in Spain, Romania, Hungary, Slovakia, and in the north of Italy by 3-4°).
In North America the abnormally hot water dominated in the west. In California the temperature rose up to 45°. New temperature records have been registered. In the west of USA and Canada the average monthly air temperature is above the norm by 2° and more. In Oregon it was the warmest month, in California – the second warmest August in the state’s history. At the same time the central and east territories of these countries had a deficiency of warmth. Here the average monthly air temperatures are below the norm.
In the Northern Hemisphere the summer of 2017 is the second warmest one on the record. Summer of 2016 was the record one. It was abnormally warm summer in Europe, in the north of Africa, in the Middle East and in some areas of the west USA, in the north of Canada and in Alaska. In Europe it is the third, in Africa – second hottest summer on the record.
In Moscow the average monthly air temperature of the last August is 18.8°, anomaly +2.4°. August in the capital became warmer than July. It happened for the second time in XXI century (firstly it was in 2007). On the average, over the last century it has happened one time in 10-12 years. The average summer temperature in the capital corresponds to the norm accurate within 0.1°. Long period of the cold weather in June and beginning of July was compensated by August heat.


Ocean Surface Temperature.

Average Sea Surface Temperature (SST) anomaly in Atlantic ocean remained at the last month level, i.e. +0.5°, in Pacific ocean – increased to 0.6°. In equatorial latitudes of Pacific ocean the neutral phase of Southern oscillation is being kept, negative anomalies of SST in El-Niño area increased their zone and became larger by the absolute value. Whether it means, that instead of new El-Niño it will be return to La-Niña, existing in the last year, one will understand in near months.
In Pacific ocean, as before, the abnormally warm water along Asian coast is being kept. Here the SST anomalies in some places exceeded +2°, the same situation in the subtropical belt.
In Atlantic ocean negative anomalies in middle latitudes are being kept for a long time.
Very warm SST is in the Arctic basin. In neighbouring Russian seas anomalies reached +3…+4°.

Precipitation.

In August in ETR an abundance of atmospheric precipitations was available only in northern and north-west territories. In Novgorod, Pskov, Leningrad, Murmansk regions the monthly precipitations norms were exceeded in 1.5-2.0 times. In the beginning of the month here the heaviest showers fell, meteorological observations showed more than 50 mm of rain over the 12 hours. In other ETR regions there were few rains. Besides, the farther to the south, the rains were infrequent. For instance, in Moscow, Ryazan, Tula, Smolensk regions the rain complete roughly norm, in the most part of Volga area it was only half-norm, and in the south of Astrakhan, Volgograd regions and Stavropol district – less than 30%. In the end of the month in Sochi mountains the early snowfalls were observed.
Urals have got less the norm of precipitations. Siberia had the norm of precipitations. But there are areas with noticeable exceeding of the precipitations norms: south of Krasnoyarsk region, Transbaikalia, with norms deficiency: Omsk, Irkutsk regions. In the end of the first and second decades the heavy rains fell in the south of Siberia. Real flood happened in Krasnoyarsk. During the night 19-20 August the city was inundated by the rains up to cars roofs.
As usual, the large variety of precipitations is in Far East. Together with the norm in Khabarovsk district, Yakutia, Kamchatka, the very few rains (50% from the norm) fell in Sakhalin, Chukotka and Kolyma. At the same time, Amur region cumulated 1.5-2.0 norms of rains, in the end of the month the snow fell there, it became the new earliest time of snow cover appearance, the previous date was later by 20 days. The snow depth reached 15 cm. In the beginning of the month heavy rains fell in Primorye. In Ussuri region near to 400 mm of rain was fallen over the day. Showers brought a large damage of infrastructure and economic activities of the area.
In neighbouring China the showers, floods and landslides happened during all month. In the first days of August the rains fell in provinces Guangdong, Sichuan, Yunnan, Guizhou. In the middle of the month the showers inundated Hunan, in the end of the month – Guizhou once again. Except north-east areas, in the other part of the country the precipitations have set the norm and more. The last regards to the coastal provinces in the east and centre. Here the precipitations norms were exceeded in 2-3 times.
South-east of Asia has got roughly the norm of precipitations. Heavy rains in the north of Vietnam in the first decade of the month caused the floods, which destroyed hundreds of houses, roads and irrigation systems, caused dozens of human losses.
In the most part of India the monthly precipitations sums have set the norm. At the same time, in the north-west of the country it was few rains, but in the east and north-east the noticeably in 1.5-2.0 times exceeded the norm. Here in states Bihar, Assam, Uttar-Pradesh and in the neighbouring Nepal monsoons caused a lot of troubles. Human losses from floods, mud flows and landslides estimate as thousands, hundreds of thousand people became displaced persons. Sri Lanka has got a lot of precipitations.
Dry weather was in the most part of Central Asia and very dry, almost without rains, in the Middle East. However, some showers and floods took place here. In the north-east of Iran the rains caused the flood with tens of casualties.
Showers fell in West Africa. In small Sierra-Leone on the Atlantic coast the heavy rains caused the floods in Freetown, the capital of the country, in was the reason of hundreds of losses.
European continent, especially its southern part, was under the umbrella of Azores anticyclone, thus it was few precipitations. Only in Germany, UK and Scandinavian countries they have set the norm, and in some places exceeded it approximately in 1.5 times.
West states of USA have got less of the precipitation norm, in some places of California with full absence of precipitations. In other areas of the country it was norm of precipitations. Hurricane “Harvey”, attacked Texas, brought up to five monthly precipitations norms. Neighbouring states of Mexico Gulf also have got it. In Louisiana and Mississippi the norms were exceeded in 2 times. The same situation is in the states, situated to the north from raged “Harvey”: Kansas and Oklahoma.
In the most part of Canada it was dry. Only in the east in Quebec province and in the north-west of Yukon they made the norm and more.
West of Mexico has got a lot of rains – 1.5-2.0 norms.
In total over the summer the precipitations sums in the most territory of Russia have set the norm and more. Only south of Russia, territories around Baikal, Amur region and Arctic areas of Far East have not got a usual set of summer rains.
China, India, South-East Asia have got the precipitations norm and more over the summer. Dry weather in this period of the year in the Middle East and Central Asia became even dryer without rains.
In the most part of Europe the summer precipitations set the norm, in the central part of the continent exceeded it in some places. At the same time, in Italy, Balkan countries, south of France it was a rains deficiency.
Very few rains last summer had the west of USA and central provinces of Canada, but in the south of USA (because of “Harvey” hurricane) and in the east of the country the precipitations had the norm and more.
Moscow in August had 68mm of rain, or 88% of the norm. Summer precipitations added to Moscow rains 310 mm of precipitations and the day before autumn their sum over 2017 have already set almost 90% of annual norm.

 
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