Decatur County Sheriff Roy Wyatt said there are forecasts of hail, wind and possibly tornadoes in the area.
Speaking Friday on NBC's "Today" show, Wyatt also said searchers would wait and see how the conditions will affect efforts to find 20-year-old Holly Bobo.
Authorities do not have any suspects in the case, which is being investigated as an abduction, said Wyatt.
Bobo, a nursing student, has been missing since Wednesday. Her older brother told authorities he saw a man wearing camouflage drag her from her home toward the woods. Several law enforcement agencies and hundreds of volunteers have searched the surrounding woods and fields.
The Associated Press contributed to this report.