Flood Watch issued September 6 at 9:51AM MDT until September 8 at

* WHAT...Flooding caused by excessive rainfall is possible.

* WHERE...Portions of northwest and west central Montana, including
the following areas, in northwest Montana, Flathead/Mission Valleys
and West Glacier Region. In west central Montana, Potomac/Seeley
Lake Region.

* WHEN...From 3 PM MDT this afternoon through Tuesday morning.

* IMPACTS...Excessive runoff may result in flooding of 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...
- Thunderstorms capable of rainfall rates of 0.75" to 1.00" per
hour are possible this afternoon and evening (Sept 6), which
could lead to localized debris flows.

This period will then be followed by prolonged moderate to heavy
rainfall Monday into Tuesday morning of an additional 1 to 3
inches in the valleys, with 2 to 4 inches in the higher terrain,
especially along the Continental Divide and in Glacier National
Park.
- https://www.weather.gov/mso/hydrology