Mistral (wind)

The winds of the Mediterranean
Tramontana Gregal Levante Siroco Ostro Lebeche Poniente Mistral

The mistral (or maestral), also known by the name of cierzo in Aragón, is a wind from the northwest (sometimes from the north), which blows from the Mediterranean coast towards the sea, between the mouth of the Ebro and Genoa. It is a cold, dry and violent wind, which currently reaches 100 km/h and can exceed 140 km/h (75 knots).. It can be caused by the nocturnal cooling of the ground in the coastal regions, but when it blows very strongly it is due to an increase in atmospheric pressure in north-western Europe: the polar air thus flows towards the low pressures of the Mediterranean and upon finding the obstacles opposed by the relief (the Pyrenees, the French Massif Central, the Alps) passes through the gaps that exist between them, then suffering a considerable increase in speed as the section of the veins is reduced.

Mistral weather conditions.

In France it is a cold wind from the north of the Gulf of Lion, caused by a depression in the Gulf of Genoa. It becomes especially intense in the Rhône Valley. It occurs at all times of the year, more so in autumn and winter. It creates a strong, cold, north-westerly current along the coast, particularly from the Rhône delta to further east of Marseilles, in the south-east of France.

The mistral is an example of a katabatic wind, caused by air being cooled over mountains by the presence of a high-pressure or radiative cooling system. In the mistral, the air cools above the Massif Central, the central plateau of France, and the Pyrenees. It blows down into the Garonne valley, because its density is greater than that of the surroundings. In the Rhône Valley, a boxing in occurs upon arrival from the heights of the Massif Central, which inevitably accelerates it, and due to its dry wind character, gives rise to the ambient light typical of Provence.

In Marseille, in half the days of the year, the weather is characterized by strong mistral winds. They affect the weather in the Balearic Islands, North Africa, Corsica, Sardinia, Sicily and Malta, particularly when a low pressure system forms in the Gulf of Genoa.