Red Flag Warning 8, NWS Missoula, MT

Area Forecast Discussion
National Weather Service Missoula MT
255 AM MDT Thu Oct 3 2024

...STRONG WINDS WITH COLD FRONT FRIDAY...

.DISCUSSION...Fair weather is expected today, with light winds,
sunshine, and highs in the 60s and 70s under a broad ridge of high
pressure.

Strong winds remain the primary forecast concern Friday
afternoon and evening as a quick-hitting shortwave trough and
surface cold front move across the Northern Rockies. South-
southwest winds will ramp up by late morning to early afternoon
Friday as the cold front tracks into eastern Washington and
Oregon. Guidance suggests the front will move along the Idaho-
Montana border by late afternoon, passing through western Montana
by early evening. Significant pressure rises (greater than 10 mb
in 3 hours) along the frontal boundary will increase the risk of
damaging winds (50-60+ mph), primarily across southwest Montana,
Lemhi County, Idaho, and the mountain ranges of west-central
Montana. The Salmon Valley and the I-90 corridor between Deer
Lodge and Anaconda stand out, with probabilities for wind gusts
exceeding 55 mph reaching 60-70%. Isolated damaging wind gusts are
also a concern across the Bitterroot and Mission Valleys, where
probabilities of gusts exceeding 55 mph are in the 15-20% range.
Convective showers along the front may allow for stronger gusts to
mix down to valley areas in these aforementioned locations.

As the front passes across western Montana, there is medium-high
confidence (70-80% probability) for advisory-level wind gusts
(greater than 40 mph) across all valley areas. Motorists driving
high-profile vehicles on Friday evening should exercise caution,
particularly along the divide and in southwest Montana and Lemhi
County. Choppy lake conditions will develop on area lakes, and
recreationalists should prepare for a sudden westerly wind shift
as the front passes.

Model ensemble guidance remains in strong agreement (over 90% of
cluster members) for a broad ridge of high pressure to build
across the Rockies from Sunday into the middle of next week.
Expect mild daytime temperatures, with crisp overnight conditions
as dry air settles into the region. /Lukinbeal

&&

.AVIATION...VFR. Light and terrain driven winds expected through
this afternoon under a ridge of high pressure. Scattered high
cirrus clouds will move into the airspace by mid-late afternoon.
/Lukinbeal

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...High Wind Watch from Friday afternoon through late Friday night
     for Bitterroot/Sapphire Mountains...Butte/Blackfoot
     Region...Potomac/Seeley Lake Region...West Glacier Region.

     Fire Weather Watch from Friday afternoon through Friday evening
     for Deerlodge/West Beaverhead...East Beaverhead.

ID...     High Wind Watch from Friday afternoon through late Friday night
     for Eastern Lemhi County...Western Lemhi County.

&&