Weather Service Report

FXUS66 KOTX 180001

Area Forecast Discussion
National Weather Service Spokane WA
501 PM PDT Sat Mar 17 2018

Bands of rain and high elevation snow will across southeast
Washington and the southern Idaho Panhandle tonight then taper off
to showers on Sunday. Elevations above 3500 feet on the Camas 
Prairie and in the Northeast Blue Mountains will have the 
potential for wet snow accumulations overnight. A showery early 
spring weather pattern is expected through Monday. A break period 
Tuesday will be followed by followed by a wet and windy frontal 
system on Thursday...with cool, showery and breezy conditions into
next weekend. 



Updated Aviation Discussion.

Tonight and Sunday: Low pressure will 
continue its eastern migration with the center over southwestern 
MT by this evening. This will result in stronger northwest flow 
into the Camas Prairie with snow expected to intensify a bit. Road
temperatures will cool back down to near freezing with snow 
covered roads and winter travel along Highway 95. Expect between 3
to 6 inches of additional snow overnight on the Camas Prairie 
with snow letting up Sunday morning. The higher elevations in the 
Blue Mountains will also see similar snow accumulations above 4000
feet. No changes will be made to the current Winter Weather 
Advisory with the afternoon package issuance. Precipitation will 
decrease on Sunday with skies clearing out in the lee of the 
Cascades and into the western basin. Lingering showers will likely
persist in the Idaho Panhandle though. /SVH

Sunday nigh and Monday...The sprawling upper level closed low 
over the western United States will minor out by Sunday night and 
Monday into a minor closed center just off the northwest Pacific 
Coast. This will leave a west to east running weakening trough 
axis dropping through the forecast area from north to south during
this period. It is likely that this axis will be the focus of
scattered lingering overnight snow showers and daytime valley 
rain and mountain snow showers mainly impacting the northeast
Washington mountains and the Idaho panhandle. the rest of the
region will see dry and partly cloudy conditions with high
temperatures near average. 

Monday night trough Tuesday night...A quiet break
period...probably the least active part of the extended forecast 
forecast...will envelop the region monday night through Tuesday
night. Tuesday will probably feature quite a bit of sunshine
around the area with seasonably normal high temperatures and light

Wednesday through Saturday...Models are in general agreement in
developing another deep upper level closed low off the Pacific 
coast...initially bringing a rainy period as deeper Pacific
moisture is caught up in the pre-trough flow and directed into the
forecast area. Wednesday will be a day of increasing clouds and
increasing chances of light valley rain and mountain snow...not a
sure bet yet but conditions will be noticeably deteriorating as
the air mass moistens up. Thursday appears to be the highest 
confidence rainy day across the area with the now saturated air
mass and probable warm front passage promoting widespread
valley/basin rain and high mountain snow.

After Thursday models remain in agreement in slowly ejecting the
offshore low inland with some models weakening it into a trough as
it does and others maintaining it's integrity as a closed low. No
matter how it end up this spells a cooler and unsettled weather
regime...likely breezy as well...from Friday onward into next
weekend. There will almost certainly be a well defined cold front
passage late Thursday or on Friday with another shot of rain...and
then snow levels will likely crash to the valley floors in an
unstable showery regime. High temperatures will be below normal
leading into next weekend and even during the day with highs well
above freezing...wet bulb cooling in the cores of these showers
may allow snow and graupel to survive down to the surface. The
mountains ringing the basin will receive the lion's share of
shower activity...but the rising terrain of the eastern basin will
also see scattered daytime rain or snow showers and overnight snow
showers. In short...Friday and saturday look to be
breezy...unsettled and raw across the region. /Fugazzi 


00Z TAFs: Low pressure will hang out over the southern ID 
Panhandle through tonight into Sunday morning. Abundant moisture 
and upslope flow into KPUW will result in VLIFR conditions at
times into Sunday morning. KLWS is expected to see rain with MVFR
cigs. Precip will wind down as the low pulls away Sunday morning.
Low stratus with MVFR/IFR cigs will be possible across the 
Spokane/Coeur d'Alene corridor Sunday morning as moisture lingers 
in the area. KMWH and KEAT will be VFR through the TAF period. 


Spokane        32  48  32  49  31  50 /  30  10  10  10  10  10 
Coeur d'Alene  32  45  30  47  28  48 /  30  30  20  30  10  10 
Pullman        33  45  30  48  31  50 /  90  30  10  10  10   0 
Lewiston       39  53  34  54  35  57 /  90  20  10  10  10  10 
Colville       30  50  31  51  28  52 /  10  10  10  30  10  10 
Sandpoint      32  45  32  45  30  47 /  20  20  30  40  10  10 
Kellogg        31  41  30  44  27  45 /  60  50  20  40  20  10 
Moses Lake     35  57  30  57  30  58 /  10  10   0   0   0   0 
Wenatchee      35  54  32  54  31  55 /  10  10   0  10   0   0 
Omak           33  52  30  51  29  52 /  10  10  10  10  10   0 


ID...Winter Weather Advisory until 11 AM PDT Sunday above 3500 feet 
     for Lewis and Southern Nez Perce Counties.

WA...Winter Weather Advisory until 11 AM PDT Sunday above 4000 feet 
     for Northeast Blue Mountains.



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Western Regional Climate Center,