Weather Tracker: Hail blankets parts of Tunisia and Algeria as snow | extreme weather

Severe thunderstorms hit the Mediterranean this week. On Monday, a surface low pressure system in the Mediterranean in conjunction with an upper air shear low led to thunderstorms across the north Africa. Their intensity was aided by the warm precursory conditions.

Algeria and Tunisia were particularly affected by the thunderstorms, resulting in some hail accumulation layers. When that much hail forms, it begins to deposit sheets of hail, covering the ground like snow. Hail accumulations of up to 3 cm were reported in Oum Ladjoul and Hammam Sokhna in Algeria, and there were hailstones up to 3 cm in diameter in Makthar, Tunisia. Thunderstorms continued in the region the next day, with further hail accumulations, particularly in Ouled Bousmir, Tunisia, where there was a layer about 2 cm deep.

Later in the week another surface low developed, this time over Sicily. Thunderstorms broke out across parts of central Italy on Wednesday morning. This resulted in some heavy downpours, with 52.1mm of rain falling in just over an hour and 10 minutes in the city of Ascoli Piceno and 62.3mm falling in less than 1 hour and 50 minutes in the town of Mosciano Sant’Angelo. Other regions were also affected, with 46mm of rain in 36 minutes in the Sicilian town of Bagheria, as well as heavy rain recorded in Algeria and Tunisia.

There have been severe thunderstorms elsewhere in the world this week, especially parts of the northeastern US. Tuesday night, a supercell touched down in Dane county, Wisconsinand as a result a tornado warning was in effect. According to radar, a tornado did occur, but there were no confirmed reports of it touching the ground. However, this supercell also produced heavy hail. Baseball-sized hailstones were reported around Madison. With a diameter of 7 cm, it would have been twice the size of those reported in Tunisia.

The next day, severe storms continued in the northeastern US and spread to Ohio. During this outbreak, even larger hail was reported, with softball-sized rocks seen near Kansas City – rocks as large as 11.5 cm in diameter.

Tornadoes have also been a big player in these storm outbreaks, with about 20 across the US this week, mainly in Wisconsin, Kansas, Iowa and Minnesota.