Area Forecast Discussion
Issued by NWS Missoula, MT

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FXUS65 KMSO 261007

Area Forecast Discussion
National Weather Service Missoula MT
407 AM MDT SUN APR 26 2015

...Snow across Lemhi County ID and higher mountain passes will
taper to showers by this afternoon...

.DISCUSSION...Snow levels are generally around 5000 feet as of 3
am MDT and may fall as low as 4000 feet in a few hours across
southwest Montana. Snow has been sticking to Lost Trail Pass while
web cams reveal snow sticking to grassy surfaces at other
locations. There is still a chance that locations across the
southern Bitterroot Valley above 4000 feet could experience a
period heavy snow for a period towards daybreak. Expect the
steady precipitation to change to showers by this afternoon.
Drying expected to occur by tonight.

High pressure quickly builds into western Montana and north central
Idaho Sunday night and lasts through mid week. This will result
in much warmer and drier conditions, with many valleys approaching
the mid to even upper 70s by Tuesday afternoon. Mornings will
start off chilly, especially on Monday morning when some valleys
of western Montana could briefly dip below freezing, perhaps locally
into the upper 20s.

Southwest flow ahead of an approaching trough Wednesday will allow
for the return of showers and slightly cooler temperatures, with a
few thunderstorms possible as well over southwest MT Wednesday
afternoon. Breezy winds can also be expected Wednesday afternoon.

Forecast models have changed course yet again for the rest of the
week and into the weekend, now showing a generally drier westerly
flow. Overall, forecast confidence is low for this period. For
now, have kept the forecast near climatology, which is generally
cooler temperatures than earlier in the week, and chances of
showers mainly over the mountains.


.AVIATION...Reductions to ceilings and visibility will continue
this morning from KBTM, west to the Bitterroot Valley then south
to KSMN. Expect improvement after 26/1800z as the weather system
moves off to the east. North to east winds to 20 knots have been
observed at weather stations along and west of the Continental
Divide. Expect these winds to diminish somewhat by after 25/1800z. Showers
are anticipated this afternoon but should decrease in coverage
after 27/0000z as an upper level ridge builds into the region.


MT...WINTER WEATHER ADVISORY until 3 PM MDT this afternoon
     Butte/Blackfoot Region.

     WINTER WEATHER ADVISORY until 3 PM MDT this afternoon
     Bitterroot/Sapphire Mountains.

     WINTER WEATHER ADVISORY until 10 AM MDT this morning ABOVE 4000
     FEET for the Missoula/Bitterroot Valleys.

ID...     WINTER WEATHER ADVISORY until 3 PM MDT this afternoon Eastern
     Lemhi County.


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