textproduct: Missoula

UPDATE

Red Flag Warning issued across the West Lolo and Kootenai National Forests 5 PM today through 6 AM Sunday for lightning and outflow winds. Red Flag Warning issued for Deerlodge/West Beaverhead from 1 PM to 8 PM Sunday due to windy and dry conditions.

PREV DISCUSSION

/ISSUED 400 AM MDT Sat Aug 22 2026/

DISCUSSION...

KEY MESSAGES:

- Strong to severe thunderstorms today through the afternoon and evening.

- Cold front Sunday brings cooler temperatures but strong westerly winds and very dry air.

- Ridge rebuilds into next week.

Light rain showers this morning depicted on radar continue to expand northward. The main convective event develops this afternoon around and after 2pm MDT. Storms will generally track from southwest to northeast. A marginal risk for severe thunderstorms covers the region, with damaging wind gusts toward 60 mph remaining the primary hazard of concern alongside small hail and frequent lightning. High precipitable water values entering the region under monsoonal flow will support brief heavy rainfall under stronger showers and storms bringing localized threats for excessive runoff and flash flooding over urban areas and within steep terrain and burn scars. Lingering showers and isolated convection will persist through the overnight as the strong to severe thunderstorm threat begins to diminish.

A cold front crossed the Northern Rockies late tonight into Sunday, ushering in a brief temperature respite with daytime highs dropping 10 to 15 degrees to near seasonal averages. Deep boundary-layer mixing behind the front will drive strong westerly winds within the very dry post-frontal airmass. Elevated to critical fire weather conditions are anticipated across the region on Sunday.

High pressure rebuilds early next week marking the return of hot daytime temperatures and generally dry conditions. Near-daily afternoon showers and thunderstorms will remain possible in southwestern Montana and Lemhi County.

Ensemble cluster analysis shows moderately high confidence (70%) in a progressive pattern returning to the region by mid-to-late next week, though details about timing and strength of any inbound troughing remain uncertain at this time.

AVIATION...Morning light rain showers will yield to strong afternoon and evening thunderstorms tracking southwest to northeast between 22/2000Z and 23/0400Z. Localized direct impacts from convection will bring erratic outflow wind gusts of 30 to 50 knots, small hail, brief heavy rainfall causing localized MVFR/IFR visibility, along with LLWS and turbulence near storm cores. Strong westerly winds develop post-frontally on Sunday on an otherwise dry and less-problematic day for aviation.

MSO WATCHES/WARNINGS/ADVISORIES

MT...Red Flag Warning from 5 PM this afternoon to 6 AM MDT Sunday for Kootenai...West Lolo.

Red Flag Warning from 1 PM to 8 PM MDT Sunday for Deerlodge/West Beaverhead.

ID...None.