A tropical storm moving across the Gulf of Mexico may bring much needed rain to drought stricken Texas.

Forecasters say Tropical Storm Don is moving fast and should make landfall on the southeastern Texas coast Friday night. 

The storm is about 500 miles southeast of Corpus Christi, Texas, moving northwest with 40 mph winds.

Don, the fourth named storm system of the tropical season, formed Wednesday evening, north of the Yucatan Peninsula.

A tropical storm watch is now in effect from the mouth of the Rio Grande northward to west of San Luis Pass.

On Galveston Island, city and emergency officials are on alert in case Don heads in their direction.

Don is not expected to reach hurricane strength, and forecasters say the storm surge may be smaller in strength as well.