Sand storm

Dust outflow boundary over Sudan

30 April 2007 00:00 UTC

Sand storm
Sand storm

The MSG image below shows a large night-time dust squall (also called haboob, from the Arabic word 'haboob' meaning strong wind) over Sudan on 29 April 2007, which is rather early for the convective season (which normally starts in May).

Last Updated

25 May 2022

Published on

30 April 2007

By HansPeter Roesli and Jochen Kerkmann (EUMETSAT)

The gust front, which during the night travelled very fast at a speed of 50km/h, was initiated by a thunderstorm system over eastern Sudan.

A second, non-dust producing gust front, coming from a storm further to the south, intersects the haboob gust front in the middle of this image without triggering new convective storms.

Note that night-time haboobs, encountering strong stratification near the ground, can transform from a relatively slow-moving gravity current into a fast-moving undular bore. This probably happened in this case as can be deduced from the high speed of the arc-shaped gust front and the 'ripples' of clouds behind the leading edge.

On 30 April in the early afternoon, a secondary dust outflow boundary started moving southwards. The cause of this second dust boundary is not clearly identifiable.

 

Dust outflow boundary over Sudan
Figure 1: Meteosat-8 Dust RGB, 29 April 2007, 22:00 UTC. Animation (hourly, 29 April 15:00 UTC–1 May 09:00 UTC)


Dust outflow boundary over Sudan
Figure 2: Meteosat-8 RGB Composite IR12.0–IR10.8, IR10.8–IR8.7, IR10.8, 30 April 2007, 03:00 UTC
Interpretation