198
FXUS65 KMSO 271857
AFDMSO
Area Forecast Discussion
National Weather Service Missoula MT
1257 PM MDT Sun Apr 27 2025
.DISCUSSION...
KEY MESSAGES:
- Showers and thunderstorms through this evening, with isolated
outflow winds up to 30 mph.
- North-northeast winds through this evening leading to choppy
lake conditions. Gusts 25-35 mph along the divide and higher
terrain.
- Widespread precipitation this evening into Monday morning
across Lemhi County and southwest Montana, with snow
accumulations above 5,500 feet.
Satellite and radar observations early this afternoon highlight
showers and thunderstorms developing over the higher terrain,
while a closed low pressure system is seen spinning along the
ID/UT/NV border. Shower and storm coverage will expand into this
evening as the low gradually moves northeastward, with brief heavy
rain and outflow winds being the primary storm threats. Storm
coverage will focus along the ID/MT border mountain ranges into
west-central Montana, where there`s a 40-50% chance for
thunderstorms over the course of this afternoon and evening.
Model guidance continues to depict a 700 mb low circulation
wrapping moisture and precipitation across Lemhi County and
southwest Montana this evening into Monday morning, with snow
levels dropping near 5,500-6,000 feet. A winter weather advisory
is in effect above 6,000 feet in eastern Lemhi County, where snow
will impact travel across area mountain passes and make for
difficult driving conditions across unimproved roadways and impact
outdoor recreation. Through Monday, precipitation totals across
valleys will range from 0.25" to 0.80", and 0.50" to 1.25" in the
higher terrain, with the higher amounts focused in Lemhi County.
Remote locations above 6,500 feet in Lemhi County will see the
highest snow amounts with 6-12 inches.
Model guidance continues to indicate that another trough will
move through the region from the northwest on Tuesday into
Wednesday, bringing breezy west-northwest winds and scattered
showers.
A warming trend is anticipated Thursday into Friday, with ensemble
model support showing greater than 90% confidence for the
development of a broad ridge of high pressure, leading to drier
and warmer conditions. Furthermore, the warmest temperatures of
the Spring thus far are in the forecast for Friday, with highs
reaching into the upper-70s and 80s across valleys.
&&
.AVIATION...A closed low over Nevada will lift northeast through
this evening, with a cold front dropping south from Canada,
leading to north-northeast winds across north-central Idaho and
western Montana. Gusty winds of 10-20 knots are expected, with
isolated outflow winds up to 30 knots from thunderstorms after
20Z. Showers and thunderstorm coverage will increase by mid-
afternoon and evening, with brief heavy rain, lightning, and
variable winds causing localized MVFR reductions, mainly at KSMN,
KBTM, and KHRF. Tonight, the low will stall over southeast Idaho,
focusing steady precipitation over Lemhi County and southwest
Montana. MVFR ceilings will become widespread, with isolated IFR
and mountain obscuration developing overnight. Snow levels will
drop to 5,500 feet with wet snow accumulations after 06Z.
&&
.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Lake Wind Advisory from 5 PM this afternoon to midnight MDT
tonight for Flathead/Mission Valleys.
ID...Winter Weather Advisory from 9 PM this evening to 9 AM MDT
Monday for Eastern Lemhi County.
&&
$$
