Sunday, July 16, 2017

Morocco's Heatwave - Understanding the "Chergui"

In a recent bulletin the Directorate of National Meteorology indicated that the very high temperatures are due to the “chergui”. The View From Fez received a flurry of emails asking "what is the chergui?"

The chergui or sharqi (Arabic: شرقية‎‎ šarqīa) is the name of a continental easterly or southeasterly wind which blows on the southernmost part of Morocco, a hot and dry wind coming from the Sahara Desert. This wind can be compared with the sirocco, a very hot and very dry desert wind.

The Arabic word means "coming from the east", as the chergui emanates from the desert east of the Atlas Mountains. This is a rain shadow wind, and it descends after passing over the top of the mountain range as very hot and dry air into the coastal plains area towards the Atlantic ocean. This brings soaring temperatures typical of the desert, often over 40 °C (104 °F), and can even bring about 48 °C (118.4 °F) during the day. The relative humidity is extremely low, nearly always below 15%.

The chergui can also (more rarely) blow in wintertime, and is responsible for warm, sunny and dry weather.


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