679
FXUS65 KMSO 312035
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
235 PM MDT Fri Jul 31 2026

.DISCUSSION...

Key Messages:

* Critical Fire Weather Conditions across Northern Rockies, Saturday
  afternoon through Saturday night.

* Choppy wave activity on area lakes for Saturday afternoon and
  evening.

* Relatively cool airmass in place Sunday through early next week,
  but summer warmth returns thereafter.

The warm ridge of high pressure currently over the Northern Rockies
will provide a few more days of hot afternoon temperatures.
Anticipate most low elevations warming into the 90s and 100s (F).
Despite these temperatures being in line with recent trends,
remember to take take frequent breaks, drink plenty of water, seek
shade, and never leaving any person or pet in a parked vehicle.
There is a 70 percent probability of showers and thunderstorms
developing across Lemhi County Idaho and portions of southwest
Montana this evening.

The ridge of high pressure is anticipated to break down Saturday
through Sunday, resulting in gusty winds and low relative humidity
across the Northern Rockies. Red Flag conditions will develop at
many locations. Those recreating on area lakes, particularly
Flathead Lake, will experience choppy wave activity Saturday
afternoon through late evening. A cold front is expected to sweep
across the Northern Rockies Saturday evening.

A relatively cool airmass is projected to rush over the Northern
Rockies Saturday night through Sunday. Gusty winds will return
during daytime Sunday and once again increase wave activity on area
lakes. However, the cooler daytime temperatures should keep
afternoon humidity a bit higher compared to Saturday.

Prepare for very efficient radiational cooling across the Northern
Rockies overnight Sunday. High mountain valleys will cool to the 30s
in many locations by Monday morning.

Long range ensembles generally agree that a warm high pressure ridge
will return to the Northern Rockies around the middle of next week.
Models also tend to agree that the next iteration of our summertime
ridge will be several degrees cooler than the current ridge.

&&

.AVIATION...
High density altitude will continue due to heat through Saturday.
Smoke from area wildfires and increasing west winds aloft will be
the main aviation weather impacts over the Northern Rockies for
the next 24 hours. Also, there is a 70 percent probability that
showers and thunderstorms will develop 31/2100Z through 01/0400Z
roughly between KSMN and KBTM. Anticipate erratic wind gusts to 40
knots near any thunderstorm that develops. Terrain will be
occasionally obscured during this time as well. A surface cold
front will increase wind gusts to 30 knots beginning around
01/2000Z.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Red Flag Warning from 2 PM Saturday to 9 PM MDT Sunday for
     Deerlodge/West Beaverhead...East Beaverhead.

     Red Flag Warning from 2 PM Saturday to midnight MDT Saturday
     night for Bitterroot...East Lolo...Flathead Reservation...
     Flathead/Glacier Park...Kootenai...West Lolo.

ID...Red Flag Warning from 11 AM to 8 PM PDT Saturday for
     Palouse/Hells Canyon.

     Fire Weather Watch from Saturday morning through Saturday
     evening for Palouse/Hells Canyon.

&&

$$