The key weather and climate features in the northern hemisphere in July 2015
  Climate The key weather and climate features in the northern hemisphere in July 2015

The key weather and climate features in the northern hemisphere in July 2015

Air temperature

In July 2015 mean air temperature in the Northern Hemisphere has reached the absolute maximum in the history of regular meteorological observations in the world since 1891. This year is the fifth month with a record high average monthly air temperature. Previous record holders - February, March, May and June.

 

It was considerably hotter than usual last month in Europe and North Africa, the Middle East, Central Asia and southern Siberia, in the north of the Russian Far East and Alaska, in the east of the Canadian Arctic and northern Pacific coast of the United States. In contrast, abnormal cold seized the central and northern regions of European Russia and the Urals, a significant part of Canada and the United States, northern and tropical waters of the Atlantic Ocean, the western part of the temperate latitudes of the Pacific Ocean and the Horn of Africa.

 

In Europe, hot weather of June passed into July. It became even hotter. In Spain, the thermometer stayed above the level of + 40°C. In France, they came close to it which for the last time was mentioned there for more than forty years ago. Even in Albion, where a refreshing breeze from the Atlantic Ocean usually makes the intense heat to go down, the air warms up to + 35°C and above. Daily maximum temperature were recorded in London. An absolute record air temperature was for the country for + 40.3°C was recorded in Germany. There was heat for 30-35°C in Central Europe and the Balkans. In the east of the continent in Belarus and Ukraine were recorded a new daily maximum temperature. Only Scandinavia fell out of this hot series. There July was cooler than norm. Almost across the continent, with the exception of Scandinavia, Scotland and Ireland, average monthly air temperature exceeded the norm by 2°C or more, and in some countries of Central Europe, the Balkans and Italy - 4°C or more.

Air temperature above the norm was recorded in North Africa and in the Mediterranean countries: Morocco, Algeria, Tunisia, Libya, as well as in parts of Niger and in the Red Sea: Egypt and Sudan - 2°C more.

To the east of the Red Sea in Saudi Arabia, Kuwait, Iraq, Oman, mean monthly temperature anomalies were even more - up to + 3°C or more. The unprecedented heat prevailed in Iran. The temperature of about 50°C was an ordinary situation there. In the west and south of the country anomalies reached + 4 … 5°C.

The superheated air from the deserts of Arabia led to a 40-45°C heat in Central Asia and southern Kazakhstan. On average for the month air warmed by 3-4°C higher than normal. Strange as it may, but the south was cooler. In Pakistan and northern India average monthly air temperature was approximately normal, or were slightly below it. In the north of India, in the province of Rajasthan anomaly was up to -1.5°C. Nevertheless, the average temperature in India as a whole was high. In Hyderabad, it was above the norm by 2.5°C, the average temperature in the country is in the top five highest values.

The temperature was varied in China. If in the central area, in the north and west of the country it was significantly warmer than normal (anomaly up to + 2 ... 5°C), in the south dominated rare for this time of year coolness. In the provinces of Hunan and Jiangxi anomaly -2 ... -3°C. It was very hot in neighboring Korea and Japan (anomalies + 2 ... 3°C). Earlier this month, Japan's air was heated to + 35-38°C. There were registered cases of deaths from heat stroke; thousands of people were hospitalized.

In North America, a wave of heat and cold replaced each other, and as a result, the average temperature for the month in Canada and the United States was close to normal, though in separate areas it is markedly different from the norm. For example, in the east of Canada in the provinces of Ontario, Quebec and along the Atlantic coast, it was colder than normal. There the temperature was below the norm by 2-4°C. Approximately the same situation was recorded in the north-west of the country. However, in the north-east in the Arctic anomaly was + 3-4°C.

On a large part of the United States in July, the weather was slightly cool. Only in Wyoming, Colorado, and Utah average temperature anomalies were up to -2°C. It was hot on the Pacific coast. There the temperature was above the norm by 2-4°C. The heat contributed to the development of forest fires. According to the US Department of Forestry, the number of fires significantly exceeds the average. Again as in previous months, it was much warmer in Alaska (anomalies + 2 ... 3°C). July 2015 is the third warmest in the history of the United States.

The average temperature in July in Russia was a little higher than normal. On the territory of the country during the month were registered both the records of the maximum temperatures, mainly in the east of the country in Khabarovsk, Primorye, Altai and Trans-Baikal, Amur, Magadan and Irkutsk region, the Republic of Yakutia and Tyva, and the minimum temperatures - in the Central District, in the north European territory, in the Volga region, the Urals and the North Caucasus. In the Komi Republic were observed freezing to -2°C.

Especially long, almost the entire month, the abnormally cold weather was kept in the North-Western, Volga, Urals and north of the Central federal district. There month was colder than normal by 2-4°C. At the European North of Russia last seen of such a cold in July was noted 35 years ago. At this time, the average temperature of the "summer crown" here was the same as in June. Approximately the same situation was in the Central Federal District.

It was abnormally warm in the south of Eastern Siberia, Baikal, and especially noticeable in the north of the Far Eastern Federal District, in the Magadan region and the Chukotka Autonomous District. There mean monthly temperature anomalies were for + 2-4°C. The average temperature of July 2015 in the north of the Far East in the meteorological chronicles is located in the 5th row among the highest values.

In Moscow, the average air temperature was 18.3°C. This is almost the norm. Especially cold in the capital was in the middle of the month. In Moscow at night the thermometer fell to + 5°C.

The temperature of the ocean surface

The growth of the average surface temperature of the Pacific Ocean (SST) in the Northern Hemisphere continued steadily. For the last 10 years, the average monthly value of SST in July has not been as high as today. El Niño is responsible for this: its intensity is growing and is now classified as moderate with the transition to strong. The average value of SST anomalies in the area of El Niño exceeded + 1ºC, and in some areas of the waters - + 2ºC. A marked influence of El Niño can be traced on atmospheric processes. For example, in South America increased intensity and total amount of precipitation. It is assumed that El Niño with 80% chance will continue until the spring of 2016.

Abnormally warm water in the Pacific Ocean spread to temperate latitudes in the eastern part of the ocean, while the west coast of Asia and east of Japan is dominated by negative anomalies of SST.

An equally large negative SST anomaly also occurred off the west coast of Eurasia, ie in the North Atlantic Ocean. In the triangle Newfoundland-Great Britain-Greenland, average values of SST were less than norm by 1ºC or more; the average temperature of the Atlantic Ocean in the Northern Hemisphere, as well as in the previous four months, was within normal limits.

Precipitation

It was heard from residents of the central region of Russia that last July was too rainy. Statistics, however, claims that it is not. In the Central Federal District monthly precipitation exceeded norm only in the Kostroma region. In all the rest regions - their sum for the month was close to the norm or even slightly less. A similar picture was mentioned in the European North. Indeed more than normal rainfall appeared in the Volga region and the Urals. In the republics of Mari El and Mordovia, in the Tyumen region, Yamalo-Nenets and Khanty-Mansi Autonomous District, they accounted for about 2 standards and more, and in the Udmurt and Chuvash Republic, Perm Krai - one and a half norm and more. In the south of Russia was little of precipitation. In the Lower Volga region, the North Caucasus and the Crimea, as a rule, fell about half of the norm of precipitation. In the south of Siberia, Tomsk, Omsk, Novosibirsk, Kemerovo region and Altai Territory, as well as to the north in the Taimyr and Evenki District an amount of precipitation was normal or more (sometimes up to two standards, and more). In the rest of Siberia - less than norm, and in Transbaikalia approximately 2 times less than norm. In most of the Far Eastern Federal District there was little precipitation. The exceptions were Sakhalin and certain areas of Magadan region. There norm was greatly exceeded: 2-fold or more.

The southern regions of China, as it should be during this time of the year, were poured by rain. Daily total rainfall reached 200 mm and more, which sometimes led to the emergency. In the provinces of Guangdong, Fujian, Jiangxi, Zhejiang precipitation norm for the month was exceeded 1.5-2.0 times. There were not so many precipitation on the rest of China.

Summer monsoon this year was late with the arrival to the South-East Asia, which caused drought in northern Thailand. Local experts estimate it as the strongest premonsoon drought for 50 years. By the end of the month the situation began to improve - in the south of the country the amount of precipitation for the month was normal, and in the north - 60-70% of it. In neighboring Myanmar rains caused floods and landslides that have harmed dozens of people, and the hundreds of thousands people became the victims of natural disaster.

Summer rains continue in India. They were particularly strong in the north of the country and in neighboring Pakistan. In one day there fell out more than 300mm of rainfall. Rainstorms caused landslides and loss of life. In some places the monthly norm was exceeded by 2-4 times. In the central and southern states of India precipitation was significantly less than norm. In general, since the beginning of the season (from 1 June) in most parts of India annual rainfall was close to normal, and in the north and northwest - slightly above it. Sustained deficit emerged in the central states (from 24 to 58%) and some northern areas at the border with Nepal (30%). Further to the north in the territory of Afghanistan and the Central Asian republics was dry weather.

On the Middle East, heavy rains went to Iran. Almost all over the country the amount of precipitation for the month was more than the norm, and in the central regions - they were exceeded by 2-3 times. At the same time the rest of the region was dry.

The same situation was in the east of Africa. There were not rains at all while in the west, there were quite enoughof them, and sometimes in the south of Niger, Chad and Burkina Fassa they exceeded the norm by 1.5-2.0 times. In addition, there were many rains in Morocco and Algeria.

In most of Europe, July was dry. Only in the north of the continent in Scandinavia, Great Britain and Ireland and along the coast of the North and Baltic Seas total precipitation for the month reached the norm, and in some places in Sweden, Finland, and especially in Scotland and Ireland, it exceeded it by 1.5-2.0 times.

Rains poured United States, Canada and Mexico in July without mercy. In large parts of these countries, their amount for the month exceeded the norm by 1.5-2.0 times. In Canada, in the provinces of Saskatchewan, Manitoba, Quebec, per day fell out up to 100 mm precipitation. Only in the far north of the country and along the Pacific coast precipitation was not enough.

Even more rain has got to the United States. In the west of the country in California and Oregon, as well as in the center of Kansas and Oklahoma to Tennessee and Kentucky their amount per month exceeded the norm by 2.0-2.5 times. In the middle of the month daily precipitation up to 60-80mm caused rain floods in the states of Kentucky and Ohio, as well as in the north-east of the country. They injured houses and outbuildings, bridges and roads were destroyed, people died. Flooding occurred even in some areas of New York. Dry this month was only in the northwest of the state of Washington, as well as in the Great Lakes and New England.

Northern Mexico also received a lot of rainfall (up to 2-3 norms), and in other territory their amount was about the norm or less.

In Moscow, the amount of precipitation in the past month was 119.0mm, which is slightly more than the norm. About the same number were in July the year before. We recall that last year July in the capital was the driest in history.

Atmospheric Circulation

In the upper stratosphere (at AT-10) anticyclone centered near the poles during the July remained close to normal intensity.

In the equatorial stratosphere was a significant weakening of the east winds phase of quasi-biennial cycle.
In the middle troposphere (at the AT-500) in the past month averaging field of geopotential in tropical and subtropical latitudes was dominated by positive anomalies. At high latitudes, by contrast, we noted very significant negative anomalies of geopotential. In the first and second decade of July, intense tropospheric anticyclones were constantly formed in the North Atlantic and over Greenland, and therefore the mean monthly geopotential anomalies near a pole amounted +17 dam. Polar vortex has been weakened and fragmented with five centers instead of one. The two most active cyclones formed over the North Atlantic (anomalies -12 dam) and over the north of European Russia (anomalies -13 dam). However geopotential at their center was on average by 5 dam above the norm. Less deep cyclonic centers were over the Laptev Sea, over the Bering Sea (anomalies to -6 dam over the Aleutian Islands) and Hudson Bay (anomalies to -2 dam). Tropospheric troughs usually took their usual places and depth and corresponded to the norm. Only over the central and eastern regions of Siberia, where during July ridges formed intensively, mode of zonal circulation was significantly impaired, and geopotential anomalies over Baikal reached +8 dam. In the first and second decades, stable tropospheric ridges were also observed over the Southern, Western and Central Europe, which led to the formation of anomalies to + 8 dam on the Adriatic Sea. Geopotential was above the norm in Central Asia (anomalies to + 7 dam), in the western Pacific (anomaly to + 4 dam to the east of Japan) and its northeastern part (anomalies to + 8 dam). Very significant for the tropical latitudes anomalies to + 4 dam were also observed in the tropics of the Eastern Hemisphere, including the Bay of Bengal and the Arabian Sea. In connection with this, monsoon depression in the middle troposphere looked very weak: instead of vast hollows over Hindustan there was formed only a small area of low pressure over the north of Bay of Bengal. Quite a vast area of negative anomalies of geopotential in the subtropics in the east Pacific (-5 dam) also should be mentioned. In the first half of the month, there was an active cyclonic activity.

The position of the planetary high-altitude frontal zone almost everywhere consistent climate. Significant deviations to the south occurred over the North Atlantic (5°C) and to the north - over Siberia (up to 5-12°C).

Zonal and meridional circulation indices were close to normal in the whole hemisphere, and on separate synoptic natural areas (NSR). A little more active than usual meridional transport in temperate latitudes II NSR, where the index was 21% above the norm.

All the same very intense anticyclone centered over Greenland attracts attention in the averaged for the past month surface pressure field, because of which in high latitudes were formed very large positive anomalies of pressure (up to 14 hPa over Greenland and up to 11 hPa over the pole). Azores High in every way appeared normal, but its northern and eastern periphery have been somewhat weakened (anomalies to -4 hPa) by active cyclonic activity that shifted to the south in July. Icelandic minimum located substantially to the south than normal, which is why in the northeast Atlantic, was formed an extensive range of negative pressure anomalies to -6 hPa off the coast of Great Britain. Most often, the Atlantic cyclones moved to the east to Scandinavia (hPa anomaly to -4), the north of Europe (the anomaly to -6 hPa), and often detained in the north of Western Siberia, being blocked from the east. There, contrary to custom, on the averaged map was marked the deepest July cyclonic center in the northern hemisphere and the pressure anomalies in the Yamalo-Nenets Autonomous District, in this regard, amounted -11gPa. Abnormally intense cyclonic activity was the cause of the cold and wet weather in all of these regions, particularly in the north of European Russia and western Siberia, where average temperatures in the past month were 3-5°C lower than normal, and the amount of precipitation 2-3 times exceeded the norm. Western, Central, Southern and partly Eastern Europe, on the contrary, languished from the heat, especially in the first half of the month, staying under the tutelage of the Azores anticyclone. The largest positive temperature anomalies were formed in northern Italy, in the Alpine countries and the Balkans. In most of these regions there is a serious shortage of precipitation.

It was hotter than usual in the Middle East, Turkmenistan and in the south of Kazakhstan. Southern Siberia was under the influence of the southern advection of warm sector of the cyclone, which was influenced by both Western and southern cyclones. However, in mid-July in the south of the Krasnoyarsk Territory prevailed anticyclonic weather. Both factors contributed to the formation of large temperature anomalies, the most significant of which occurred on Lake Baikal. Influence of warm advection were also subjected to the north-eastern regions of Asia. Active cyclonic activity has led to the formation on the average monthly map of the independent cyclonic centers over the Magadan region (anomalies to -3 hPa), over the Bering Sea (anomalies to -5 hPa) and Alaska (anomalies to -4 hPa). South advection in warm sectors of cyclones and radiation heating in the field of high pressure in the first and third decades of the month provided a very warm and dry July in Chukotka and Alaska in the west. In the eastern Yakutia, in the zone of cyclones and their fronts, monthly amount of precipitation was much higher than the climate norm. There were many precipitations in the Far East of Russia, where summer monsoon fully emerged. Heavy monsoon rains were on the east and southeast of China.

Monsoon depression in depth and position broadly consistent with the norm. Negative anomalies to -2 hPa were observed in the western part of it (the Arabian Peninsula), and over Bay of Bengal. The Indian monsoon is still shown very uneven. During July, very heavy rains

Hawaiian anticyclone continued to dominate in the Pacific pare of atmospheric centers of action in July. The northeast ridges in the first half of the month were very active and often interacted with polar ridges. As a result, averaged map anticyclone center shifted to the northeast and anomalies near the center of pressure amounted 3 hPa. Its western ridges that were distributed in the first two decades of July up to Japan were intensive (to anomalies +4 hPa to the east of the Japanese islands). However, the northern periphery of the anticyclone was weakened by the cyclonic activity over the Bering Sea (anomalies -5 hPa), and the southern – by the very active tropical cyclogenesis in the central and eastern Pacific Ocean (anomaly to -4 hPa in the north of the Hawaiian Islands). Trajectories of unusually active Pacific cyclones were mostly in the south of Alaska, western and southern Canadian provinces, and in the first and second decade of July – in the Midwest United States. Almost everywhere on the North American continent, pressure background was lowered in July. Pressure anomalies were estimated at -3 ... -5 hPa in Canada and -2 ... -3 hPa - in the West and Midwest. Climate cyclonic center, which normally resides over Davis Strait, last July, was dismissed on the Hudson Bay (anomalies to -5 hPa) and represented an extensive area of low pressure that took up the entire center and east of Canada. Displacement of Canadian cyclones to the east often hampered by the blocks in the west of the Atlantic, so their impact on the eastern regions of Canada and US was often long. As a result, in the north and in the center of Canada under the influence of cold rears of cyclones July temperatures were significantly below normal. Cooler than usual was on the Great Plains. Temperatures above normal were observed in the western United States and in the Great Lakes. In most parts of the continent, temperatures were close to normal. A large number of rain fell in southern Alaska, in the western and eastern Canadian provinces. Much more than the norm of rainfall was almost throughout the United States. Most often, intense downpours with thunderstorms and hail were associated with heightened edges of Pacific cyclones.

In the tropical zone of the northern hemisphere in July twelve tropical cyclones occurred at a rate of 8.8.

In the west of the Pacific Ocean were formed three cyclones (the norm for 4.1). Two of them became very intense typhoons. Typhoon "Nangka" at its peak had a central pressure of 925 hPa and wind speed near the center of more than 50 m / s, gusts - up to 70 m / s. July 16, it hit the south of the island of Honshu with winds of about 40 m / s and rains to 197 mm / day. Then it was on the Sea of Japan, hitting Primorye with the strong winds and rains. Even more intense typhoon was "Sodelor" that emerged in late July. The minimum pressure at its center was 900 hPa, and maximum wind - 60 m / s, in gusts up to 90 m / s. Its trajectory was dangerous: in the beginning of its path, when it was a typhoon, it was on the Northern Mariana Islands, causing considerable damage. Then its southern rain bands caused heavy rains and flooding in the north of the Philippines. August 8, typhoon hit north Taiwan with wind speeds up to 40 m / s. In the northeast of the island have been recorded gusts of 60 m / s. Less than in a day on the northeastern Taiwan fell 1334 mm of precipitation. Then, a day later, a cyclone left to the east of China, which also recorded strong winds (gusts up to 45 m / s) and rainfall up to 392 mm / day. The destruction was very serious, more than 20 people were killed. A strong tropical storm "Linfa" was much less intense, but it was on the north of the Philippines, and then went out to the southeastern China with heavy rains.

In the northeast and center of the Pacific Ocean existed 7 cyclones (norm for 3.7). In the east of the Pacific Ocean, two of the four became hurricanes, one of which, "Dolores", whith the fourth hurricane category (Pmin - 944 hPa, vmax - 60 m / s with gusts of more than 75 m / s). However, their paths were not dangerous.

Extremely active tropical cyclogenesis was observed in the central part of the Pacific Ocean, where in July continued the development of El Niño, ocean surface temperature was significantly higher than normal. There appeared three cyclone, and one of them, "Halol" reached the stage of a hurricane (Pmin - 955 hPa, vmax - 45 m / s with gusts up to 60 m / s). It was unusual in its trajectory. Having existed for 16 days and come a long way across the Pacific, “Halol” completed it in the Sea of Japan, which caused the winds up to 35 m / s and heavy rains. As the extratropical cyclone it influenced the weather of Primorye and Khabarovsk Krai.

There was a tropical cyclone in the north of the Indian Ocean (Bay of Bengal) in July (the norm for 0.1). Cyclone was pretty weak, inactive, but it had larger dimensions. For a long time it had been influenced east and northeast India, Bangladesh and Myanmar. Especially it hit Myanmar, whose territory was almost completely flooded. In some places in three days therefell up to 1000 mm precipitation, in the northeast of India - up to 800mm. Floods and landslides in these areas took the lives of 126 people.

In the Atlantic Ocean, in July there was a cyclone at a rate of 1.7. The cyclone formed on 35º N, it was weak, short-lived and did not provided an impact on the coast.

 
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