The National Weather Service reported very large hail greater than two inches and a tornado or two could not be ruled out during Wednesday's commute home.
The best chances for severe weather begin around 3 p.m. Wednesday afternoon and continue to around 6 a.m. on Thursday.
There is a higher risk of severe weather during that same time frame for Val Verde County, Edwards Plateau, the Hill Country and Central Texas.
Forecasters said high winds and rainfall of two inches or more was possible for some spots.
More than half of San Antonio was expected to see rain by dawn on Thursday.
Forecasters said cold air shooting up the slopes of mountains in Mexico will collide with warm air over South Texas to trigger the storms.
Shower chances quickly taper off after daybreak on Thursday.
Friday morning will see widespread haze and fog. The weekend looks to be a mostly cloudy with highs in the upper 80s.
