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Rare rain event over the Sahara, the northward shift of ITCZ could bring years’ worth of rainfall in 2 weeks

A rare rainfall event is forecast to occur over the Sahara Desert within the next two weeks and could continue into the following month, according to a report by Andrej Flis of Severe Weather Europe, published on August 27, 2024.

A large part of the Sahara could get over 500% of normal rainfall in August and September.

The central regions of the Sahara are expected to receive almost 1 000% of the normal rainfall for August.
Such events are rare, happening less than once per decade, indicating an unusual state of the atmosphere.
This unusual rain event is attributed to the northward shift of the Inter-Tropical Convergence Zone (ITCZ), a critical weather pattern that influences tropical climates. The ITCZ is a belt of clouds, rain, and storms that typically hovers near the equator, where trade winds from both hemispheres converge. Currently, the ITCZ has shifted unusually far north, bringing moisture and rain deeper into the Sahara.

The European Centre for Medium-Range Weather Forecasts (ECMWF) shows significant precipitation anomalies over the Sahara, and Global Forecast System (GFS) models indicate that some regions could receive several years’ worth of rain over the next two weeks. The central regions of the Sahara are expected to receive almost 1 000% of the normal rainfall for August.

GFS models forecast a rainfall of 254 mm (10 inches) in some regions of the Sahara. To put this in perspective, most of the Sahara receives 25 mm (1 inch) of rain annually.

The ECMWF extended precipitation anomaly for early September also shows a large portion of the Sahara Desert under significant rainfall anomalies. A considerable part of the desert is expected to experience rainfall even into September.

Although complete data isn’t available yet, 2024 is forecast to be the second wettest year for the Sahara since 1994, when a similar event occurred in the region.

The shift in the ITCZ could also impact the Atlantic hurricane season. The northward shift could cause strong thunderstorm systems to move into the Atlantic Ocean at higher latitudes over colder waters, leading to fewer tropical systems intensifying as they move out of Africa.