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Area forecast discussion 
National Weather Service Spokane Washington
413 am PST Friday Feb 12 2016

Synopsis...
a cold front will pass through the region today with continued
precipitation chances and slightly lower snow levels. Unsettled
weather will continue through the weekend into early next week
with valley rain, High Mountain snow and breezy winds expected.
Temperatures will be quite mild on Monday with many locations
seeing highs in the mid 50s to low 60s. Record high temperatures
are possible.

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Discussion...
today through Sat nt: frontal passage later this morning will
produce a continued threat of valley rain and High Mountain snow
accumulations...especially across nrn WA and north Idaho zones, as
well as the east slopes of the Cascades. Heavy mountain snow
accumulations are not expected with snow levels Above All passes.
The exception may be from Sherman Pass and west toward the Methow
Valley where cold air damming has keep temps cool. Snow amnts and
pcpn type will be monitored closely. Breezy winds across the
Palouse are possible later today under the Post frontal dry slot.
Saturday morning should be the most interesting part of the fcst
as the upper trough moves quickly across the region. The result
will be lowering snow levels and increased mid-level instability
as temps aloft cool markedly. Though all zones may get at least
isold showers in this pattern, NE WA and the Idaho Panhandle will
be the focus region due to the upslope component. The heaviest
snow accumulations are expected above 4000 feet with valley towns
remaining mostly rain. Later Saturday and Saturday nt will see a
big pattern shift to a much more stable (but more widespread) pcpn
event along a zone of warm advection/isentropic ascent that moves
quickly into the region. This second wave could produce some heavy
mtn snow accumulations above 4k ft msl for the Idaho Panhandle.Bz

Sunday through Thursday...models continue to show an atmospheric
river of subtropical moisture aimed at the North Washington
Cascades into the Idaho Panhandle Sunday into Monday. Westerly
850mb winds of 25-40 kts will lead to a large rain shadow east of
the Cascades with pop's mostly in the 20-40 percent range during
this period. This pattern will bring in warmer air along with
breezy conditions. Near record high temperatures are forecast for
several areas on Monday. Areas with low/mid elevation snow such
as the Waterville Plateau, some of the mountain valleys, and the
Idaho Palouse will see significant rises on area rivers and small
streams due to snow melt...as well as moderate rain totals of 1-2
inches in the Idaho Panhandle. The Cascade crest will also see
significant rain (2 to 5 inches) but the deep snow pack should
absorb most of the rain that falls. A hydrologic outlook has been
issued to address this situation. A break in the weather is
expected on Tuesday before the next upper trough approaches
Wednesday into Thursday with mild southwest flow favoring high
snow levels once again. The latest GFS and European model (ecmwf) models show much
of the energy splitting with this trough with general light precip
totals for the area. Jw

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Aviation...
12z tafs: a cold front passage will spread light rain showers across ern
WA and north Idaho this morning. VFR conditions will prevail for the
most part. But behind the rain, stratus and fog development may
lower cigs/vsby to MVFR and possible IFR. Expect conditions to
improve back to VFR for most areas after 18-21z today. After Sat
00z-06z, the next round of more widespread light pcpn will once
again bring ceilings down to at least MVFR.

&&

Preliminary point temps/pops...
Spokane 47 34 45 35 47 42 / 50 60 40 70 30 40
Coeur D'Alene 47 36 45 34 46 41 / 60 70 60 70 50 60
Pullman 53 38 47 37 50 44 / 30 70 40 100 50 50
Lewiston 57 41 54 42 56 45 / 20 50 30 90 40 40
Colville 40 33 43 33 42 38 / 80 50 50 60 30 40
Sandpoint 40 34 41 33 41 39 / 80 90 60 70 60 70
Kellogg 42 35 39 33 40 40 / 70 90 80 90 80 90
Moses Lake 49 34 51 37 52 42 / 40 20 10 50 20 10
Wenatchee 44 33 46 33 47 40 / 40 20 10 50 20 20
Omak 42 30 41 30 40 36 / 70 20 10 60 20 10

&&

Otx watches/warnings/advisories...
Idaho...none.
Washington...air stagnation advisory until 10 am PST Saturday for Moses Lake
area-northeast mountains-Okanogan Highlands-upper Columbia
Basin-Waterville Plateau-Wenatchee area.

Air stagnation advisory until 10 am PST Tuesday for east slopes
northern Cascades-Okanogan Valley.

&&

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