330
FXUS65 KMSO 230810
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
210 AM MDT Thu May 23 2024

..HEAVY SNOW IN THE HIGHER TERRAIN ACROSS LEMHI COUNTY INTO
SOUTHWEST AND WEST-CENTRAL MONTANA THIS MORNING...

.DISCUSSION... Satellite imagery this morning is showing a well-
formed midlevel circulation over Lemhi County and southwest
Montana. This feature is pulling moisture up from the south and
wrapping it back around into southwest Montana and central Idaho.
Temperatures are cold enough for snow down to valley bottoms. The
valleys will see some accumulation on grassy and elevated
surfaces. Heavier accumulations will occur over about 5000 feet,
where impacts due to snowfall rates over 1 inch per hour will
include downed trees and potential for power outages. A Winter
Storm Warning will remain in effect for the Butte/Blackfoot
Region, the Bitterroot/Sapphire Mountains, and the Missoula and
Bitterroot Valleys through this morning`s commute.

There will be a break between systems to end the week, though the
region will remain under a cool, showery pattern.

Memorial Day weekend will start off on Saturday with another
cutoff low moving into the region and causing high elevation snow.
All guidance so far is pointing to an overall warmer system with a
little less precipitation. So fewer snow impacts, but a cool and
wet start to Memorial Day weekend. Conditions will improve
through the weekend with above average temperatures by Monday.

The pattern remains unsettled next week. Model ensembles are in
good agreement for a 2 to 4 day period dominated by a ridge after
the holiday weekend.


&&

.AVIATION...Low pressure over southwest Montana is bringing
widespread snow and rain showers to the Northern Rockies airspace
this morning. Expect precipitation, heavy at times, to obscure
terrain throughout southwest Montana and central Idaho and lower
ceilings and visibility at KMSO, KBTM, KHRF, and KSMN through
about 23/1800Z. Northwest winds to about 20 kts will accompany
snow at KBTM through this morning.



&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...     Winter Storm Warning until 10 AM MDT this morning for
     Missoula/Bitterroot Valleys.

     Winter Storm Warning until noon MDT today for
     Bitterroot/Sapphire Mountains...Butte/Blackfoot Region.

ID...Winter Weather Advisory until noon MDT /11 AM PDT/ today for
     Eastern Lemhi County...Southern Clearwater Mountains...
     Western Lemhi County.

&&

$$