Viz >500m during usual duststorm
<500m during the Haboob.
Vertically usually tops out at about FL100, duststorms are a daily occurence and landing not really a problem. Haboobs are caused by approaching CB and the viz goes to nothing...landing not possible.
The ILS for 18/36 is currently serviceable and takes you down to minimas (200') but the viz has to be greater than 1200m to commence approach. ATC will let you commence if less than 1200m.
Port Sudan is the primary alternate...+-1hr at 350kts...fuel available, good approach procedure and fairly decent Hilton.