The possibility of heavy rainfall has elevated the flood threat for a large portion of Iowa through Friday morning (Aug. 12, 2016).

The National Weather Service (NWS) has posted a flash flood watch for several counties until 7 a.m. Counties included in the watch are: Benton, Black Hawk, Bremer, Buchanan, Butler, Chickasaw, Delaware, Fayette, Floyd, Franklin, Grundy, Hardin and Tama.

A flash flood watch means that conditions may develop that lead to flash flooding.

According to NWS, torrential rainfall is possible late Thursday afternoon (Aug. 11) through early Friday morning. High rainfall rates in excess of two inches per hour combined with slow storm motions and possible training of storms will lead to the potential for flash flooding.

Forecasts said rainfall amounts of one to three inches may be common where the storms persist. Rainfall totals of four to six inches are possible in some localized areas.

NWS said rapid rises on local streams and creeks will be possible, and water may cover roadways.