A slow-moving storm system is forecast to drench parts of Minnesota and Wisconsin from Sunday evening through Monday night, raising the prospect of localized flash flooding, meteorologists said. Heavy rain had already soaked southern Minnesota early Sunday, and additional thunderstorms are expected as a cold front sweeps across the state later in the day, according to FOX 9 in Minneapolis-St. Paul. The National Weather Service office in Milwaukee warned that storms could produce rainfall rates exceeding two inches an hour, prompting a “slight” risk designation in its Excessive Rainfall Outlook. While widespread flooding is not anticipated, the agency cautioned that slow-moving and training cells may trigger flash floods and cause river levels to rise in vulnerable basins. Conditions should begin to dry out from Tuesday as the system moves east, with drier air and lower humidity forecast for the middle of the week.