Area Forecast Discussion
Issued by NWS Boise, ID

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FXUS65 KBOI 042215

Area Forecast Discussion
National Weather Service Boise ID
315 PM MST Sun Dec 4 2016

.SHORT TERM...Tonight through Tuesday...Showers continue this
afternoon with the rain/snow line at about 4000-4500 FT MSL. Received
a report at about 2 PM MST of 6-8 inches of snow accumulation in
Yellow Pine since this morning. Other areas have not seen such
generous amounts, but will hold off expiring the Winter Weather
Advisory in the W Central and Boise Mtns until after the cold
front passes through the area. Surface observations indicate that
the front has passed through Baker County from the northwest.
Latest model guidance has the front passing through McCall by 4 PM
MST, Boise around 5 PM MST, and Twin Falls around 7 PM MST. No
longer expecting a rain/snow mix with frontal passage in the
Treasure and Western Magic Valleys as temperatures have warmed
too much ahead of the front. Much cooler temperatures will follow
for Monday`s high and low temperatures with snow levels dropping
off significantly for the near future. Patchy fog in sheltered
mountain valleys expected to develop in the morning, burning off
before noon. A weaker and drier system is set to move into the
region as early as Monday evening and spread light snow showers
across the region through the day Tuesday. Temperatures will be
8-10 degrees below normal for both Monday and Tuesday.

.LONG TERM...Tuesday night through Sunday...Cold air mass will keep
temperatures below freezing across all of southeast Oregon and
southwest Idaho through Wednesday night. The upper level pattern will
transition from northwest flow to a moist westerly flow by Thursday.
The Pacific moisture will bring snow to the area on Thursday, with
snow levels starting at valley floors. Snow levels will rise across
the higher terrain of southeast Oregon Thursday night and southwest
Idaho on Friday as the mild Pacific air mass works inland. However,
the cold air will take longer to scour out at lower elevations in the
Snake Plain, which could result in light to moderate snow
accumulations before the changeover to rain. Friday remains cold
with snow continuing in the mountains and a cold rain likely by
late in the day across the lower valleys. Cold and unsettled
conditions will continue into the weekend as a long wave trough
remains positioned over the western U.S.


.AVIATION...IFR and widespread mountain obscuration across mountains
of east-central Oregon and west-central Idaho this evening due to
snow and low ceilings. Snow levels of 4-5k feet with low VFR and
local MVFR at sites below 4k feet. A cold front passage this evening
will bring a brief period of gusty northwest winds to 25 kts to non-
sheltered sites. VFR most sites tonight into Monday with sheltered
mountain valleys seeing fog development early Monday morning. West
winds aloft of 30-50 kts up through 10k feet MSL.


ID...Winter Weather Advisory until 8 PM MST this evening IDZ011-013.



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