Severe thunderstorm and dust warnings were issued by the National Weather Service in Tucson on Wednesday, Aug. 20.

Heat warnings remain in effect for the two counties until Saturday night, with a slight chance of thunderstorms.

A severe thunderstorm warning has been issued for southeastern Phoenix and part of the East Valley is already being affected.

This article originally appeared on Arizona Republic: Storm warning issued for Phoenix area; thousands of people without power Locations impacted include Mesa, Chandler, Gilbert, Tempe, Avondale, ...