Air temperature

 

This April in the ETR may be considered relatively warm: it was among the fifteen warmest ones in 133 years of regular meteorological observations. The monthly-averaged temperature in most of the ETR was 2-3° higher than normal during the whole month and up to 5° higher in the first and third decades. New daily maxima were recorded in the centre and in the Russian North. At the same time, the colds broke far to the south on individual days, with frosts down to -4° amid the blossom of fruit trees and shrubs in the Volgograd and Astrakhan Regions as well as in the Stavropol Territory.

The weather in the Urals and in Siberia was entirely different: the record-breaking colds were observed there, and new daily temperature minima were set in the Krasnoyarsk and Altai Territories, in the Republic of Altai and in the Baikal region. The temperature averages were 5-10° lower than normal in the first and second decades of the month, and the warmth in the third decade came to the north only, with the south still under the spell of abnormal colds. The monthly-averaged air temperature in the Siberian Federal District was 2.6° below the normal value.

In the Far East, the weather was very unsteady, frequently changing from warm to cold and vice versa. In the north, the cold in the first decade gave way to the warmth in the second and third ones, whereas the scenario in the south was exactly opposite: the average air temperature was 3-5° above normal in the first decade, and sub-normal in the second and third decades.

Eventually, the air temperature monthly-averaged over the territory of Russia turned out to be close to normal. The warmth in the ETR and in the Far East was balanced by the cold in Siberia. The monthly-averaged temperature in the Central and Volga Federal Districts was in the Top Ten of highest values in the history of meteorological observations since 1891.

The Siberian colds reached Mongolia and Northern China; however, negative anomalies of the monthly-averaged temperature did not exceed 1° in the latter case. The average temperatures of April in the centre and south of China as well as in Korea and Japan were about normal.

The monthly-averaged temperature in the South-East Asia was also close to normal this April, although in the third decade, heat came to Thailand and raised the thermometer readings to above 40°, which felt like 50° due to high humidity. The weather service of the country claimed that this April was the second warmest in the history of meteorological observations.

At the same time, heat unprecedented for this month of year occupied India where new temperature maxima in excess of 40° were reported. Such heat usually precedes the summer monsoon, i.e., comes at the end of May, but now it happened a month earlier. Yet, generally cool weather in the first half of April prevented this heat from significant overriding of the normal monthly value.

The region of really hot weather was Central Asia where the monthly-averaged air temperatures exceeded the normal values by 2-3 or more degrees. New daily temperature maxima, with new unprecedented values for April among them, were recorded in Turkmenistan and Uzbekistan, and exceeded +40°. Nevertheless, the invasions of colds did take place even there: the air in mid-April cooled below 0° in some locations, or even below -10° in the north of Kazakhstan.

The monthly-averaged temperature in the Near and Middle East was approximately normal, except for the north of Iran where the weather was noticeably warmer than usual.

Normal temperatures were recorded in most of North Africa save for its north-west part where hot weather prevailed, and they were exceeded by two or more degrees. The thermometer readings in Morocco would rise above 40°.

In Europe, the monthly-averaged air temperatures were roughly normal. At the beginning of the month, abnormally cold weather occupied Eastern Europe and cooled the air to 0° and below, while at the end of the month, hot air from Africa penetrated to the Iberian Peninsula, and the temperatures rose above +35° sometimes resulting in their new daily maxima in certain locations. The monthly-averaged temperatures in Spain and Portugal were two or more degrees higher than normal. This April in Spain was the warmest in history.

The weather in most of Canada was abnormally warm. The temperatures were 2-4 or more degrees higher than normal in the north, close to normal in the east, but lower than usual in the centre and west of the country: by 2° lower in some places. In the US, the temperatures were generally close to normal, against the background of weak positive anomalies in the east and of negative ones in the west of the country. But in Alaska, this April was very cold, with the monthly-averaged temperature anomalies reaching as low as -4…-6°, so that the month was the fourth coldest April in the history of meteorological observations.

The average temperature in the Northern Hemisphere closed the Top Ten of highest values in the history of regular meteorological observations on the planet.

In Moscow, the average air temperature was +9.7° implying an anomaly of +2.8°. This April in the capital, alongside April 1999, was the fifth warmest in the meteorological chronicle. April 2000 preserved its leadership: it was warmer than this month by almost 1.5°.

 

As previously reported, La Niña, the cold episode of the Southern Oscillation, terminated in the Pacific Ocean, and was replaced by the neutral phase. Yet, the situation was quickly evolving towards the advent of El Niño, the warm episode of the Oscillation. High positive SST anomalies up to 1…2° were already observed in the east of the equatorial latitudes off the coast of South America along with positive SST anomalies up to 1…3° at temperate latitudes in the centre of the Ocean. Negative anomalies reaching 1…2° took place in the north of the Ocean and off the coast of North America.

In the Atlantic Ocean, high positive SST anomalies were observed again both in the western and eastern parts of the Ocean. The absolute maxima of the monthly-averaged SST were recorded for the fourth month in succession: this had never been observed before. Negative SST anomalies were solely present in local water bodies near Newfoundland and off the coasts of Greenland and Scandinavia.

According to NOAA, the average SST in the Northern Hemisphere regained the absolute maximum for April set in 2020. And what is interesting, both in 2020 and in 2023, it occurred during the neutral phase rather than the warm episode (El Niño) of the Southern Oscillation.

In the ETR, a severe shortage of precipitation was felt in the Volga region: its monthly amount in many locations was 2-5 times less than normal. But on certain days in the middle of the month, rains with snow hit some areas, the Saratov and Orenburg Regions for example, and set new maxima of daily precipitation totals.

The other region of the ETR with lacking precipitation was the North-West Federal District where snowfalls were still observed every so often.

Precipitation in the central region of Russia was close to normal, or above-normal in the south (e.g., 1.5-2.0 times the normal amount in the Belgorod and Voronezh Regions). Pouring rains passed across the east of the Black Earth region in the third decade. New maxima of daily precipitation totals were set in the Voronezh, Lipetsk and Belgorod Regions.

A lot of rains fell in the south of Russia: the monthly precipitation totals were exceeded by 1.5 times in Kalmykia, Dagestan, Karachay-Cherkessia and the Rostov Region, and by two or more times in the Crimea, Krasnodar Territory and Adygeya. Unprecedented rains took place in the Crimea at the end of the month to result in new maxima of daily precipitation totals in Simferopol and a number of other locations; there, up to 50-60 mm of rainwater accumulated per day.

The weather in the Ural region and in the south of Western Siberia was dry. Precipitation in the other regions of Siberia was about normal, or increased. A snowstorm descended upon Krasnoyarsk where the snow cover was in place in October already, and continued to grow since then. The situation was similar in the Cis-Baikal Territory where up to 60% of the monthly precipitation total fell on some days.

With the exception of Chukotka, precipitation everywhere in the Far East was abundant, e.g., 2-3 times the normal amount in Kamchatka.

In China, the monthly precipitation totals were normal or increased in the north and east, but expressly lacking in the south which suffered from scarce atmospheric moisture. Precipitation in the countries of South-East Asia was sub-normal.

The precipitation figures in India and Pakistan were normal or increased. In Pakistan, downpours caused floods in Balochistan and Peshawar.

Downpours and floods were also observed in some areas of the Near and Middle East. In the Negev desert located in the south of Israel, the normal annual amount of precipitation fell in a matter of a few hours. Heavy rains in Saudi Arabia caused catastrophic floods in the first half of April. Torrential rains pelted in Iran. Snow fell on the coast of the Aegean Sea in the west of Turkey. But in monthly terms, the weather in this region can be considered dry.

Dry weather prevailed in Central Asia as well, leading to a drought in Turkmenistan. In the middle of the month, the snowfall inundated Astana, the capital of Kazakhstan, where the height of freshly fallen snow amounted to 20 cm.

The weather in North Africa was dry, with sub-normal precipitation almost everywhere.

In Europe, the monthly precipitation totals varied a great deal. Indeed, they were noticeably less than normal in Spain, Portugal, southern France and northern Italy in the south of the continent as well as in Belarus, Poland and the Baltic countries in the east, were normal or increased in Northern and Central Europe, but much higher than normal in the south-east (in Ukraine, Greece, Moldova, the Balkan countries and southern Italy), 2-3 times higher in some areas. Heavy showers led to flooding in Italy. Snow fell in Serbia, Romania and Moldova where the height of freshly fallen snow reached 50 cm in some places.

In the western United States, precipitation was scanty, or altogether absent in some regions of California, Arizona and New Mexico. But the east and south of the country received it in abundance, 2-3 times the normal amounts in certain places. Heavy rain caused flooding in Florida. Up to 600 mm of daily rainwater was recorded in some regions, amounting to figures never observed there before. Dry weather reigned in most of Canada where Quebec and certain locations in the North-Western province were the only places to get either normal or slightly increased precipitation amounts.

In Moscow, the monthly precipitation total was 31mm. This is 84% of the normal value.

 

* The air temperature anomalies have been calculated basing on the normal values for 1991-2020, the anomalies of precipitation totals in the Northern Hemisphere, on the normal values for 1961-1990, and the anomalies of precipitation totals in Russia, including Moscow, on the normal values for 1991-2020.