From the National Weather Service:
FLOOD WATCH IN EFFECT FROM 10 PM MDT THIS EVENING THROUGH LATE TUESDAY NIGHT
* WHAT...Flash flooding caused by excessive rainfall is possible.
* WHERE... A portion of northeast Montana, including the following areas: Central and Southern Valley, Dawson, Garfield, McCone, Prairie, Richland, Western Roosevelt and Wibaux.
* WHEN...From 10 PM MDT this evening through late Tuesday night.
* IMPACTS... Excessive runoff may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations. Creeks and streams may rise out of their banks. Flooding may occur in poor drainage and urban areas.
* ADDITIONAL DETAILS...
- Given recent excessive rainfall in the area and good model agreement, the next upcoming storm system has the potential to bring periods of moderate rainfall to portions of northeast Montana. Typical flood-prone areas may see standing water or nuisance flooding during this time period. -
http://www.weather.gov/safety/flood
PRECAUTIONARY/PREPAREDNESS ACTIONS...
You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued.