The National Weather Service in La Crosse, Wis., has issued a tornado watch until 9 p.m. for counties in southeastern Minnesota, including Mower, northeastern Iowa and west central Wisconsin.

At 6:20 p.m. the NWS asked that storm spotters in the county be activated.

Radar showed a line of storms was building in the region, oriented on a southwest to northeast line and moving northeast.

The NWS says to prepare for possible severe weather, and move indoors if warnings are issued.

A flash flood watch is also in effect through Monday for Mower and five other area counties. Two rounds of severe thunderstorms are possible. Storms will develop south of Interstate 90 then lift north across the area through mid afternoon.

Large hail, damaging winds, flash flooding and an isolated tornado are all possible, the NWS says. There could also be occasional thunderstorms from Tuesday through Wednesday. The primary concern, the NWS says, is localized flooding.