Europe will end the first month of the meteorological spring season 2022 by experiencing a huge cold wave this week. It is expected to last into April. A widespread cold, with snow and possible morning frosts, will affect most of Europe. First, west Europe will be affected from Friday through Saturday. Then central Europe and the southern Mediterranean will follow over the weekend.
The winter season 2021/2022 was mild in many parts of Europe. There was no snow or severe cold outbreaks. The reason was also the quite intense Polar Vortex at the top and the decaying La Nina worldwide circulation. The vortex finally weakened and collapsed a few weeks ago, but the cold weather didn’t say the last word just yet.
This week, the general weather patterns over Europe and North Atlantic have changed to a progressive northerly circulatory. An upper High has developed over the Atlantic region and Arctic region, allowing for a deep, easterly trough to form on its eastern end, moving south towards Europe. It is releasing a lot cold air, which is not welcome in the spring season.
The blocking pattern will continue over the Atlantic for several more days, with the trough at its east literally locked in the central and southern regions of the European continent. This normally brings about unsettling weather conditions due to the formation of a Mediterranean surface depression. A much-needed shower is expected for the southern and central parts of the country, which has been very dry since February. Some areas may see even more rain.
The Mediterranean region’s increasing pressure has also contributed to a significant rise in Saharan dust advection towards Europe from the Algerian deserts on Wednesday. This reaches far north across central Europe, the Balkans and even into western Europe. From many areas, dust cloud particles accumulations were reported.
However, the strengthening of the trough will increase the cold weather. Therefore, temperatures will drop further in the coming days. Close to around 15 °C below normal in the lowest levels from Friday, April Fool’s Day, through the weekend.
This will also trigger snowfall across western and central Europe as the interaction of moist, southerly air mass with colder northerly air will result in the formation of snow.
Forecasters predict accumulation of snow from eastern France, Benelux, south-central Germany, Czechia, South-Poland, Ukraine, and parts of the northern Balkans, as well as the Alps.
The average temperature for Thursday through Monday will be significantly lower, especially in central and western Europe. Clear skies are likely to bring about very cold mornings and possible frosts, especially on Monday morning. This could make it vulnerable to early agriculture and blossoming fruit trees in many areas.
A LARGE BLOCK HIGH OVER THE ATLANTIC. DEEP TRAOUGH WITH COLD OVER EUROPE AS SPRINGSEASON ENTERS APRIL
The establishing weather pattern over Europe will lead to a textbook intrusion by the cold northerlies towards Europe starting this Thursday. The upper High has been steadily building over the North Atlantic this week, and is now expanding towards Greenland.
This allows the cold to turn east on its eastern side, resulting in a large depression at the surface over central Europe and the Mediterranean.
As you can see, the temperature chart below shows how the tight pressure gradient between High and Low drags the cold across Scandinavia to western Europe first on Thursday. Then, it spreads further south into southwestern Europe or Iberia on Friday.
The surface cyclone, which will be large Thursday night into Friday, will gradually expand into the Balkan peninsula. A strong warm advection, which will be directed towards the north and spread over the southern Balkans, Turkey and the Black Sea region, will be at its front.
From Thursday midday to Friday, precipitation will be developing with the surface low. This will lead to rainfall south and eastern of the Alps. As the temperature drops, rain will become snow on the northern side.
Although the snowfall shouldn’t be too heavy, accumulation snow is expected in the wake of the surface-low across eastern France and Benelux. You can also find the southward-moving cold front, which will continue through Friday night, further east in southern Poland and Czechia.
The Atlantic surface high-pressure will be moving southward towards western Europe on Friday. This will allow the deep low and cold over Europe to move further south and south. Spreading across central Europe, and into the Mediterranean Sea for this weekend.
Temperatures in the lowest levels of the atmosphere will be very cold for the spring season, even more than 15 °C below normal in some areas. Particularly France, Benelux countries, Germany, Czechia and Slovakia, as well as Poland.
The cold will continue to affect the continent through Monday. The strong High in the west is still almost at the same place until Sunday night. And the surface depression further south over Mediterranean should also remain.
QUITE SOME WINTER AROUND THE ALPS MAJOR RAINFALL – APENNINES AND WESTERN BLKANS
As mentioned, the position and strength of the surface high pressure system extended across the Atlantic, Western, and also Northern Europe. This allowed for the north-northeasterly’s ability to drag unseasonably cool air mass far south into central Europe, and into the Mediterranean. This allows the large surface cyclone, which is also maintained into the weekend.
Because of the large upper core low that sits above it, the low actually covers a large portion of central and south Europe. The blocking pattern to its east and north is completely locked in.
Sometimes, precipitation can be very heavy and sometimes excessive due to moist southwesterly winds. Strong orographic precipitation is experienced on the Apennines, which run along the Italian peninsula and the Dynaric mountain range of the western Balkans. It will last for approximately 72 hours.
On Sunday mornings in the western Balkans, 200-500mm of rain seemed quite normal.
The coldest part of the low will be on the north side. This means that the cold at the lowest levels will already reach ground level. Therefore, rain will become snow in the lowlands around Alps. You can also find it in the northern Balkans as far south as Slovenia.
Snow accumulations are expected in the Alps. However snow could also be seen across the Apennines if there is a stronger cold on Saturday. There could be a lot of snow in central Germany, especially at higher elevations.
Strong northerly winds will result in orographic snowfall on Friday, Saturday. This is a classic heavy snowfall that is expected to occur over the northern Pyrenees. A little snow is expected to fall on higher ground in northern Spain.
MAJOR COLD WITH FROOSTS COULD FULFILL ON SUNDAY MORNING AND MONDAY MORNING
The potential for morning frosts is one of the biggest concerns when cold weather patterns arrive in the spring season. Despite March being very dry in many places, the warmth of the past two weeks has helped to accelerate the growth of many areas. In the valleys, fruit trees are beginning to bloom. Valleys are more at risk when there is a severe cold outbreak in spring.
Because cold is more dense than warm air, it tends to accumulate near the ground. Large valleys can store this cold more easily than the warmer air, so temperatures are lower than at higher elevations.
Morning near-surface temperatures on both Sunday and Monday morning will be much colder than this week’s in many areas, even very low in the valleys.
With 2m temperatures being locally even more than 10-12 °C below normal, this should bring well below freezing April mornings across western and central Europe.
The cloud cover and winds on both days will determine how low temperatures fall. Temperatures will fall more when there is clear skies and no clouds. This is because radiation from the ground reaches the sky, cooling the ground.
Below is the Sunday morning forecast. Even well below -5 °C is forecast across southern Germany and Czechia.
Monday will also have cold temperatures in the morning, particularly for the western parts of Europe. This is because high pressure will bring more calm conditions. Temperatures could drop to freezing easily.
The morning lows could reach down to around -5 °C in parts of France, Germany, and Benelux again.
The phases of the trees will determine how much danger these low temperatures and cold seasons could pose to the beginning vegetation and early stages for blossoming fruit trees. A combination of strong frost and several degrees °C below zero could form especially in the valleys.
Images used in this piece were provided by Windy and Pivotalweather.
Source: Severe Weather