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Area forecast discussion 
National Weather Service Spokane Washington
439 am PDT Tue Oct 25 2016

a few showers will linger in the mountains today then a wetter
more widespread rain event arrives Wednesday, with the potential
for moderate to locally heavy rainfall across the east slopes of
the northern Cascades. Occasional wet weather will then continue
at times through the end of the week.


today through occluded front bearing rain showers
will pass through far eastern Washington and the Idaho Panhandle
early this morning. As this front passes any location...probably
the Spokane and Pullman area around 6am and crossing the border
into Montana by 10 am or so...showers will taper off to probably
non-existent in the Columbia Basin and isolated to scattered over
the high terrain of the Idaho Panhandle...driven by orographic
enhancement of the continued moist Post front air mass. Models do
suggest a weak secondary wave clipping the northwestern part of
the forecast area scattered showers are expected to
continue on-and-off over the high terrain of the Cascades and the
northern mountains through the day. Otherwise the basin will enjoy
a break period with some sunbreaks but noticeably cooler
temperatures than yesterday...back to around or slightly above
normal with some breezy conditions developing over the exposed

Tonight and Wednesday models are in good agreement in depicting
the arrival of another wet storm system generated by the
stationary mother low off the Pacific coast. This will be a wet
warm front with a gradual onset of light rain starting late
tonight over the southern zones and creeping northward during the
morning and culminating in a sustained and widespread light
isentropic precipitation event for just about the entire region
through the day Wednesday. Only the southeastern zones south of
Pullman can expect to see any tapering off of this rain late
Wednesday morning and replaced by merely cloudy and breezy
conditions. Elsewhere the rain will continue into Thursday.

Wednesday night through Saturday night...wet and generally rain
weather continues on Wednesday night as a portion of a frontal
zone that initially passed through earlier as a warm front stalls
out and moves slowly eastward as an occluded frontal zone. Well
maintained moisture feed into this occlusion allows for the
continuation of wet weather/prolonged rainfall Wednesday night and
and into Thursday, but by Thursday the zone is over the north
Idaho Panhandle more than over eastern Washington. Conditionally
unstable air in a weak trof behind the occlusion passage allows
for lingering lower pops for precipitation behind it over the
remainder of eastern Washington. Some pops linger over north Idaho
Thursday evening but another low pressure system moving up along
the northern California coast pumps up a brief negatively tilted
ridge over eastern Washington and north Idaho Thursday night into
Friday allowing for pops to further decrease/decline until that
system moves through Friday night/Saturday. Saturday night there
is enough clutter associated with minor disturbances between this
exiting storm system and another approaching to allow a continued
mention of precipitation but with slightly lower pops in
comparison to the earlier portion of the weekend. Temperatures
will continue to trend on the warm side of normal given the
prolonged interval of warm south to north trajectories of approach
and exit provided by this longwave pattern. Winds on Thursday
night night may be a bit more breezy/gusty due to the passage of
the occluded front. /Pelatti

Sunday through Tuesday...models in decent agreement that the
low situated off the coast for the first half of the weekend will
move onshore by Sunday and weaken as it does so. This will mean
another shot of rain for the inland northwest but where and how
much is still uncertain. The GFS pins the best forcing over our
southern zones, especially over southeast Washington and central Idaho
Panhandle. The European model (ecmwf) however allows the warm front to reach
further north and thus good isentropic ascent for widespread rain
over the area, before the cold front crashes in. In either case,
look for a rainy period in the Sunday afternoon thru Monday
morning time frame. Beyond this, models diverge further but a
continued showery pattern appears like a decent bet. Temperatures
cool gradually into early next week back to their seasonal
normals after being a few degrees above normal on Sunday. /Kalin


12z tafs: a cold occluded front running from kszt to kalw at 12z
will move to the Idaho/Montana border by 18z. Rain showers with mainly VFR
ceilings but some brief periods of MVFR will persist over the
kgeg area taf sites and possibly at the kpuw taf site until 16z
with partial clearing and VFR conditions afterward for the rest of
the taf period. Kmwh and keat are well behind this front in a drying
air mass and will experience VFR conditions through 06z Wednesday.
Late tonight after 06z a warm front will develop over southern Washington
and move northward...bringing lowering cigs and an onset of -ra
at the klws... and possibly the kgeg area taf
sites after 09z.


Preliminary point temps/pops...
Spokane 56 45 53 47 55 43 / 30 20 100 80 60 40
Coeur D'Alene 56 44 53 47 55 43 / 50 20 100 70 70 40
Pullman 57 46 58 48 57 45 / 30 40 90 30 60 40
Lewiston 63 49 62 50 61 48 / 30 30 70 20 60 20
Colville 55 40 49 45 53 41 / 50 10 100 90 60 20
Sandpoint 53 40 47 44 52 40 / 80 10 100 90 70 40
Kellogg 52 42 51 45 54 42 / 70 30 100 50 70 50
Moses Lake 61 46 55 47 58 42 / 10 20 100 80 40 10
Wenatchee 60 44 52 46 57 44 / 10 20 100 80 40 10
Omak 58 41 50 46 55 42 / 20 10 100 90 50 20


Otx watches/warnings/advisories...


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