Weather Service Report

FXUS66 KOTX 270932

Area Forecast Discussion
National Weather Service Spokane WA
232 AM PDT Thu Oct 27 2016

More rainy and gloomy weather is expected through today as a slow
moving frontal system moves through the Pacific Northwest. There
should be a break in the wet weather on Friday, but more showery
conditions will move into the region over the weekend and persist
into next week.


Today through Friday...In the wake of yesterday's warm front passage 
much of the forecast area is in the dry warm sector of the
frontal complex early this morning. This break will end later this
morning as the trailing cold occlusion sweeps through the
forecast area...dropping off the Cascades and through the western
basin around sunrise and sweeping slowly across the remainder of
the Washington zones during the day today...and passing through
the Idaho Panhandle this evening. There are some model differences
in timing the speed of this front...which may delay an onset of
the second round of rain particularly over the eastern zones by an
hour or two...early afternoon versus late morning...but the
frontal forcing fed with a deep Pacific moisture feed will
virtually guarantee more rain at just about every location in the
forecast area. The western zones will see this precipitation
mainly in the morning hours and may very well dry out this
afternoon as post frontal westerly mid level flow becomes dominant
and produces a rain shadow in the cascades lee. The eastern zones
will be wet and rainy mainly during the afternoon. Another
quarter to locally half inch of rain is probable with this frontal

Tonight latest models are in generally decent agreement in
beginning a drying trend as a weak upper level ridge begins to
build into the region in the wake of the storm system. Lingering
showers will continue overnight only in the orographically
favorable mountain zones...but a saturated boundary layer in the
valleys and much of the Columbia Basin will assure a damp
overnight period with plenty of low clouds and areas of fog. 

Friday will be an essentially dry break period in the latest storm
parade...with some hope of sunbreaks as a weak push of drier
continental air leaks in from the north and helps erode morning
stratus fields and fog banks. /Fugazzi 

Friday night through Monday night: The Inland NW remains in an 
active pattern, with several opportunities for precipitation and
slightly above normal temperatures. First Friday night a ridge
moves in but the next system will be approaching from the
southwest. In the early evening isolated upslope showers are
possible across the northern mountains. Later in the evening and
overnight fog will be possible, especially in the sheltered
northeast valleys and near bodies of water. Otherwise the region
look clear to partly cloudy and dry until later overnight. The
approaching warm front will bring some increased higher clouds
from the west to southwest. It will also bring a chance of showers
toward the Cascades, southeast WA and the lower ID Panhandle. A
better threat of rain spreads in through the day Saturday into
Saturday evening as the warm front lifts in and the cold front
quickly pushes by on its heels. Most areas will see a threat of
precipitation, but some higher amounts will be possible near the
Cascade crest and southeast WA through the central and southern
Panhandle. Between late evening and the overnight the main threat
of precipitation starts to shift into the mountains. Snow levels
will be around 5000-6000 feet near the Cascades and northern
mountains up to between 6500-8000 feet toward the central
and lower Panhandle and southeast WA.

Then between Sunday and Monday night the pattern and confidence
in the forecast details starts to be muddied by a split flow, with
potential shortwaves arriving from the southwest and the west and
west-northwest. Depending on how that split evolves these waves
may more directly impact the area with higher precipitation
amounts or merely glance the area. Either way precipitation
chances will be on the rise again. First much of Sunday looks
mostly dry, save for some lingering shower chances over the
northern mountains and southeast CWA in proximity to a stalled
front. Then Sunday night one shortwave approaches from the southwest.
The GFS takes it more directly into the eastern CWA with a higher
precipitation chances and amounts, while the ECMWF keeps the brunt
of the system south with lighter precipitation chances. Yet either
solutions comes with some modest precipitation returning to the
southeastern CWA. The confidence is lacking over how much 
precipitation. This will continue to be fine-tuned. At the same
time a second shortwave approaches from the west-northwest and a
third approaches from the west, from the Pacific. Some solutions
quickly string that second shortwave across region between Monday
and keep the third shortwave of the coast and on more southern
trajectory that would keep it from having little to no direct
impact. Other solutions hold that second shortwave back in
deference to the third shortwave which makes a more direct track
into the Pacific Northwest. The second solution is not the dominate
solution so preference right now goes first, which supports
lingering but lighter shower chances through Monday before the
risk starts to retreat to the mountains Monday night. /J. Cote'

Tuesday through Thursday... Models in good agreement that a
split flow pattern will continue to influence the region mid next
week. This will leave us void of any significant weather systems
for a couple of days. Given the occasional passing of a weak
disturbance here and there, as well as for forecast consistency
sake, left some small rain/shower chances with the highest
chances in the mountains. I think this period will largely be
characterized breaks from the rain for many areas but again,
because of the lack of run to run consistency in the models, felt
it was appropriate to leave some generic precip chances in there.
The next potential quick hitting widespread rain chance could be
knocking on our door by as early as Wednesday but the GFS and
ECMWF are still at odds on the the timing. High temperatures will
remain near their seasonal norms but breaks in the cloud cover may
allow our overnight lows to cool back into the 30s and low 40s.


06Z TAFS: Much of rainfall associated with the warm front has
moved out of the area to the north. The trailing cold front will
be very slow moving and likely not cross east of the Cascades
until Thursday afternoon. There is an abundance of low level
moisture across much of the region, except over southeast WA and
into the southern to central ID panhandle where rain was not as
plentiful. IFR/LIFR conditions are expected at KEAT, KMWH, KGEG,
KSFF and KCOE tonight into tomorrow. VLIFR conditions will be
possible at times at KGEG with 1/8-1/4 SM vis possible, especially
once low level winds veer to the south and southwest late tonight.
The weakening easterly flow at this time will also allow moisture
to creep into KPUW and KLWS with MVFR/IFR conditions possible in
the morning. Very little to no improvement is expected tomorrow,
except possibly at KEAT and KMWH in the afternoon. /SVH


Spokane        52  43  54  42  52  42 / 100  30  10  10  40  50 
Coeur d'Alene  52  43  52  42  52  43 / 100  50   0  10  40  60 
Pullman        53  44  55  44  55  44 / 100  40   0   0  50  70 
Lewiston       58  46  58  47  58  47 / 100  30   0  10  40  70 
Colville       52  42  52  40  51  40 / 100  40  10   0  20  40 
Sandpoint      51  41  50  38  49  39 / 100  60  10  10  30  60 
Kellogg        50  40  50  40  50  42 / 100  80  10  10  50  70 
Moses Lake     55  42  56  42  54  40 /  80  10  10  10  50  30 
Wenatchee      55  44  55  43  53  41 /  50  10  10  10  50  20 
Omak           55  42  54  41  52  40 / 100  20  20   0  40  40 




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