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Area forecast discussion 
National Weather Service Boise Idaho
317 am MST Friday Dec 19 2014

Short through Saturday...first of two systems
arrives today...bringing steady rains to the lower valleys and
snow to the higher elevations. Showers have already moved into southeast
Oregon and portions of SW Idaho /including the Treasure valley/
altough precipitation amounts have been light. The steadier precipitation will
move into southeast Oregon in the next few hours...and then into most of
SW Idaho by mid-morning. Quantitative precipitation forecast amounts are still on track...with
generally 0.10-0.25 inches rainfall totals in the valleys. Snow
levels will average 3500 feet this morning...then rise to
4000-4500 feet this afternoon. Snow amounts of 1-2 inches are
expected between 4000 and 5000 feet...with up to 6 inches possible
in the northern mountains above 6500 feet. The first system will
depart this evening for drier weather tonight. The leading edge of
the second and much wetter system /which will bring copious
precipitation to the region through early next week/ will spread
widespread precipitation back into southeast Oregon and most of SW Idaho on
Saturday. Snow levels will average 3000 feet in the morning and
rise to around 4000 feet in the afternoon. Snow accumulations of
1-2 inches are possible in portions of southeast Oregon /including Burns
and Baker City/ by the afternoon...with higher amounts in the
mountains. Temperatures will remain above normal both days.

Long term...Saturday night through Friday evening...a moist flow
will continue Saturday night through Monday. Snow levels will be
rising through the day Sunday as a surface front brings enhanced
precipitation and warmer temperatures. By Sunday...snow levels will rise
to nearly 9000 feet in southeast Oregon and around 6000 feet in central
Idaho. In the valleys...a steady rain during Sunday and Monday
could bring nearly a half an inch of accumulation...while the
highest peaks in the west central mountains could see up to 24
inches of snow. Lower Mountain areas...snow will
turn to rain early Sunday morning which will melt previous
snowfall. On Tuesday...a ridge of high pressure will continue to
amplify off of the coast of Southern California pushing moisture
to our north and drying things out through Wednesday middle day. On
Wednesday evening...another trough will be working its way inland
and flattening out that ridge and bringing the area another chance
of rain and snow. At this point...models have been trending weaker
and warmer with this system so uncertainty lies in snow levels and
temperatures. That trough will move east quickly leaving the area
in a cooler northwest flow late Thursday.


Aviation...rain and snow showers are expected through much of
Friday. VFR conditions expected in valleys...with occasional MVFR
ceilings with heavier rain showers. However...snow levels will be
3000 to 4000 feet so mountain areas can expect MVFR/IFR conditions
with mountain obscuration. Surface winds expected to remain below
15 kts. Winds aloft to around 10k feet mean sea level...west/southwest at 15-25

Weekend outlook...a brief break in showers will occur late Friday
night but another round of rain and snow will move in Saturday
morning and continue through Sunday. This system will raise snow
levels to around 8000 feet in southeast Oregon and 6000 feet in central Idaho
by Sunday morning. Winds will also be increasing through this time.


Boi watches/warnings/advisories...




long term....ep

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