908
FXUS65 KMSO 231741
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
1141 AM MDT Thu Jul 23 2026

.DISCUSSION...

KEY MESSAGES:

-  Strong to severe thunderstorms this afternoon and evening
   across north-central Idaho, tracking toward the Montana state
   line. Hazards include gusts up to 60 mph and up to 1-inch
   hail.

-  Elevated fire weather (hot, dry, breezy) starting Friday and lasting
   into the weekend region-wide.

-  Worsening wildfire smoke degrading air quality and reducing
   visibility.

The region remains on the western periphery of a large- scale
upper-level ridge. Persistent synoptic descent and subsidence
aloft will maintain, hot, dry, and smoky conditions with no
widespread precipitation anticipated through the weekend.

Despite broad subsidence, localized thermodynamic forcing will
help to trigger strong to severe convection today (1:00 PM - 10:00
PM). Effective shear (~40 kt), modest CAPE (~1,000 J/kg), and
high DCAPE (~1,500 J/kg) will support organized discrete storms
initiating near the Snake River canyon in north-central Idaho
tracking northeastward to the ID/MT border. The strongest storms
in this environment will be capable of producing damaging winds up
to 60 mph and hail up to 1-inch in diameter. Climatologically
high moisture availability (PWATS > 1 inch) will yield brief
heavy downpours, but rapid storm movement will prevent concerns
for flash flooding. There is a 10-20% chance that decaying storms
reach the I-90 corridor late this evening which may bring a gusty
outflow threat to the area.

Breezy southwesterly winds Friday through Sunday will combine with
low humidity and hot temperatures to elevate fire weather
concerns. Red Flag Warnings are not currently being issued due to
live fuels and soil moisture remaining relatively high for this
time of year and wind speeds only on the edge of what would be an
immediate concern for fire weather products. Nonetheless,
elevated fire weather conditions and increased active fire
behavior is to remain expected on any active burns or new
ignitions.

Deep SW flow will continually transport Washington and Oregon
wildfire smoke into ID/MT, maintaining poor air quality and
decreased visibilities across the region. No Heat Advisories are
planned as of yet due to overnight temperature recovery and
shading from smoke limiting absolute maximum temperatures during
the peak of the afternoon hours.

&&

.AVIATION... Wildfire smoke (FU/HZ) remains the primary prevailing
hazard, causing periods of MVFR visibilities through the next
couple days especially noticeable near sunset, through the
overnight and into mid-morning with some clearing each afternoon
due to deep mixing. Ridgetop winds increase to about 30 knots
through today out of the west and southwest with surface wind
gusts as high as 30 knots possible region-wide during peak
heating.

Strong to severe convection today mostly targets KGIC from
23/2200z to 24/0300z (isolated gusts up to 60 mph possible, hail
up to 1 inch in diameter). Activity decays to the northeast near
I-90 where prob30 groups remain for elevated winds at KHRF and
KMSO.

Hot temperatures, especially Friday, will impact aircraft
performance particularly at higher-elevation terminals like KBTM.


&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...None.
ID...None.
&&

$$