181
FXUS65 KMSO 042016
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
216 PM MDT Fri Oct 4 2024

.DISCUSSION...The wind continues to be the main concern for the
next 12 to 24 hours. Strong southwesterly winds are already
develop across portion of north central Idaho over Lemhi county
into southwest Montana. These southwest winds are combining with
extremely low humidity readings creating critical fire weather
conditions. This combination should last through the afternoon
into the evening hours.

Next is the cold front which is just moving into central
Washington and Oregon. Several weather observations on the lee-
side of the Cascade crest have already gusted into low to upper
40 mph range this afternoon. This front is expected to move into
northwest Montana by mid afternoon and push across the region
through the remainder of the day into the late evening. This front
will cause strong westerly winds to mix down to the surface
during this passage. Areas around Orofino and northern Camas
Prairie in Idaho have a 30-50% chance of experiencing wind gusts
greater than 50 mph during the frontal passage. While areas along
and east of the Hwy 93 corridor in western Montana have a 40-90%
chance of gusts greater than 50 mph. Lakeside to Hot Springs
Montana, west-side of the Bitterroot valley and Anaconda region
have a 30-60% chance of gusts higher than 60 mph.

Multiple warning and advisories are in effect for the impacts
these winds will have to the Northern Rockies this afternoon and
evening.

The front will also bring widespread precipitation to the region,
but the winds will negate the amount that reaches the valley
floors. Clearwater County up along the Montana/Idaho border have
a 60 to 90% chance of receiving a tenth of an inch of rain. While
Idaho County and northwest Montana have a 20-40% chance of a
wetting rain. Lemhi County and southwest Montana have a low
probability of receiving any precipitation. Snow levels will start
off around 7000 feet during the onset of precipitation and lower
to around 5000-6000 feet by Saturday morning. The highest peaks of
the Bitterroot range up across the Bob Marshall wilderness into
Glacier National Park should anticipate 1 to 3 inches of snow
accumulation by Saturday morning.

A ridge of high pressure builds back over the Northern Rockies
this weekend and lasts through at least mid next week. This ridge
will cause a warming and drying trend for the region with
relatively light afternoon westerly winds. Around 25% of the
models are showing a weak disturbance moving through the region by
the end of next week, but details are fairly limited on the
impacts from this feature other than increased west winds.


&&

.AVIATION...
Gusty southerly winds are already being experienced at KBTM and
KSMN this afternoon. KHRF should have gusty south winds around
04/21z then turn westerly after 05/01z. The frontal passage is
expected to move through KGPI around 04/23z with gusts around
38kts. KMSO is expected to be impacted by the frontal winds after
05/00z with gusts approaching 48 kts. KBTM is expected to have a
wind shift to the northwest around 05/03z. KSMN should experience
a decrease in winds during the evening then have a wind shift
around 05/04z. This front will also bring in clouds with steady
lowering of the ceilings. Widespread precipitation is expected
across north central Idaho into northwest Montana, but
precipitation will steadily decrease in intensity over southwest
Montana. Snow levels will start off around 7000 feet this evening
and lower to between 5000-6000 feet by Saturday morning.


&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Red Flag Warning until 10 PM MDT this evening for Deerlodge/West
     Beaverhead...East Beaverhead.

     High Wind Warning until 3 AM MDT Saturday for
     Bitterroot/Sapphire Mountains...Butte/Blackfoot Region.

     Wind Advisory until 11 PM MDT this evening for Kootenai/Cabinet
     Region...Lower Clark Fork Region.

     High Wind Warning until 3 AM MDT Saturday for Potomac/Seeley
     Lake Region...West Glacier Region.

     High Wind Warning until 11 PM MDT this evening for
     Flathead/Mission Valleys...Missoula/Bitterroot Valleys.

ID...Red Flag Warning until 6 PM PDT this evening for Palouse/Hells
     Canyon.

     Wind Advisory until 7 PM PDT this evening for
     Orofino/Grangeville Region.

     High Wind Warning until 3 AM MDT Saturday for Eastern Lemhi
     County...Western Lemhi County.

&&

$$