Area Forecast Discussion
Issued by NWS Missoula, MT

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FXUS65 KMSO 262005

Area Forecast Discussion
National Weather Service Missoula MT
205 PM MDT Wed Apr 26 2017

.DISCUSSION...Many locations across the region have seen fairly
steady precipitation so far today, but some locations are now
seeing breaks of sun in the clouds. This will aid in instability,
particularly across central ID and NW MT, where isolated
thunderstorms are likely later this afternoon through this
evening. Brief gusty winds are also likely, as well as heavy rain
and/or graupel showers from any passing storms.

More steady rainfall will occur overnight tonight, with snow
levels lowering across the entire Northern Rockies by Thursday
morning. Overall, snow levels could fall to around 3500 feet. This
will cause light snow to accumulate on grassy surfaces and
vehicles overnight. For the Glacier Park/Whitefish/Northern
Flathead region, a Winter Weather Advisory has been issued, as
more measurable snow (1-3 inches) could occur through sunrise
Thursday morning. Impacts from snow will likely be isolated to
Highway 2 from Essex to Marias Pass, as well as GNP.

Snow showers will be common across NW MT through the day Thursday
and Friday as well, but amounts will be minimal. Elsewhere, rain
showers will continue, making for a dreary, drab end of the week.

Saturday: A shortwave will move across the area during the day allowing
for isolated to scattered showers. It seems like the best chance
for shower activity will be in the afternoon as the atmosphere
warms up causing marginal instability. Main impacts from showers
will be the large 10 to 15 degree drop in temperatures, wind gusts
to 30 mph and small hail or graupel.

Sunday: There is good confidence that a Pacific system will move
through causing a higher chance for precipitation and more
widespread coverage of showers. Westerly winds could cause enough
drying from downsloping to keep the chance for precipitation
lower in the Bitterroot Valley and portions of southwest Montana
in the afternoon and evening. Breezy winds are also possible as
the trough moves through the area.

Monday and Tuesday: Northwest flow will keep showers and slightly
cooler than normal conditions in the forecast. There could also
be a slight chance for a few isolated thunderstorms especially
across northwest Montana each day.

Wednesday: Models are becoming more aligned for a upper level
ridge to build over the Pacific Northwest which will bring a
warming and drying trend for the area.


.AVIATION...Conditions are cooler than average for this time of
year with the jet stream south of the region and moist, westerly
flow. A shortwave in that moist, westerly flow tonight will cause
showers to increase with a weak occluded front moving through the
area. Frequent ceiling and visibility restrictions will be the
norm tonight, especially at terminals KGPI and KMSO. With the
cooler than normal air, expect snow later tonight. Due to the long
days and relatively warm ground, little if any snow accumulation
is expected at area terminals.


MT...Winter Weather Advisory from midnight tonight to 8 AM MDT
     Thursday West Glacier Region.


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