* WHAT...FLASH FLOODING CAUSED BY EXCESSIVE RAINFALL IS POSSIBLE. * WHERE...A PORTION OF SOUTHWEST MONTANA, INCLUDING THE FOLLOWING AREAS, GALLATIN AND MADISON COUNTY MOUNTAINS AND CENTENNIAL MOUNTAINS, NORTHWEST BEAVERHEAD COUNTY AND RUBY MOUNTAINS AND SOUTHERN BEAVERHEAD MOUNTAINS.

* WHEN...THROUGH THIS EVENING.

* IMPACTS...EXCESSIVE RUNOFF MAY RESULT IN FLOODING OF RIVERS, CREEKS, STREAMS, AND OTHER LOW-LYING AND FLOOD-PRONE LOCATIONS. FLOODING MAY OCCUR IN POOR DRAINAGE AND URBAN AREAS.

* ADDITIONAL DETAILS... - SLOW MOVING THUNDERSTORMS CAPABLE OF PRODUCING HEAVY RAIN ARE EXPECTED WEDNESDAY AFTERNOON AND EVENING. - HTTP: WWW.WEATHER.GOV SAFETY FLOOD