Spokane, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

562
FXUS66 KOTX 231805
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
1005 AM PST Mon Dec 23 2024

.SYNOPSIS...
Unsettled weather will continue for much of this week, with mild
temperatures and precipitation falling primarily as valley rain
and mountain snow. Check mountain pass forecasts and conditions
often before traveling. Periods of heavy mountain snow will be
possible late in the week.

&&

.DISCUSSION...

Today through Wednesday (Christmas) morning: An active, unsettled
pattern continues with more rounds of precipitation in store for the
Inland Northwest through the week. Aside from lingering post-frontal
showers over the Cascades and Idaho panhandle this morning, dry
conditions will prevail through the day today thanks to a shortwave
ridge passing through, but precipitation will resume tonight into
tomorrow as a compact low pressure system makes landfall along the
coast of British Columbia, bringing snow to the Cascades and
northern mountains and rain elsewhere. Another brief lull in
precipitation will occur Wednesday (Christmas) morning and afternoon
before a more robust system moves in Wednesday evening. Mild
temperatures and snow levels above 3000 feet will stick around
through Monday morning, so snow in the lowlands is not anticipated
with the exception of a few flakes possible in the colder Cascade
valleys. With mountain snow in the forecast, checking pass reports
frequently will be crucial for those with holiday travel plans.

Probabilities for 4, 8, and 12 inches of snow accumulation at
mountain passes tonight through Wednesday morning are as follows:

Stevens Pass: 100%, 65%, 10%
Blewett Pass: 55%, 5%, 0%
Sherman Pass: 85%, 5%, 0%
Lookout Pass: 30%, 1%, 0%

/Fewkes

Wednesday night to Sunday: The Inland NW will remain in a
progressive pattern with a series of systems pushing across the
region, which will keep a good chance for precipitation just above
every day with a mixture of snow around the mountains and the
Cascades valleys and mix of rain and snow elsewhere.

Wednesday night (Christmas night) to Thursday night is the period
which continues to looks like the most significant system of this
week, which could impact those holiday traveling, especially
going over the passes. A moisture rich warm front lifts into the
area Wednesday night, with a supporting upper trough on its heels.
This will mean increasing precipitation from the west starting
later Wednesday afternoon (about 4 PM PST), enveloping much of the
area overnight into Thursday. This has the potential to carry the
most significant snow of the week. The highest amounts are
forecast to be near the Cascades and secondarily over the northern
mountain and Idaho Panhandle mountains. This includes the primary
mountain passes, including Stevens. Elsewhere snow or rain/snow
mix is expected to start, except for the deeper Columbia Basin and
L-C valley where mainly rain is expected.

Snow amounts: Around the Cascade crest, especially Stevens Pass,
snowfall accumulation rates near 1 inch per hour are possible
Wednesday afternoon and night, dropping to about 0.5 inches per
hour Thursday. Well over 1 foot of snow is possible for Stevens
Pass, perhaps approaching 2 feet by Friday morning. Other
mountains passes such as Blewett and Sherman could see 8-12
inches, maybe a bit higher at Sherman. Lookout Pass could see 6-8
inches or so, with 1-3 inches at Fourth of July Pass. As for areas
away from the passes, the Cascade valleys such as the upper
Wenatchee and Methow could see 3-8 inches, with local amounts near
1 foot around the upper Methow. The Camas Prairie, the Waterville
Plateau and the northern WA and north ID valleys could see 0.5-3
inches with locally higher amounts near Republic. The remainder of
the lowlands will are expected to see more rain than snow, thus
limiting snow accumulations. Some areas that we will have to
monitor, however, will be areas along and north of US-2 over the
Upper Columbia Basin into the north to eastern Spokane into
Kootenai county, as well as the higher Palouse. Right now
temperatures may be too mild to support much accumulation, but
still if temperatures shift just a few degrees cooler there could
be more snow. Even then, the potential for accumulations more than
an inch or so is low.

Aside from the snow, rain amounts near a half inch or up to
three-quarters of an inch are possible for areas that see rain or
a rain/snow mix. The exception in the L-C Valley which could see
about two-tenths. Some rises are possible on smaller creeks and
streams. Places like Paradise Creek near the Pullman-Moscow area
will be monitor. There is not really much low level snowpack, so
the risk of significant flooding is low. However ponding of water
in low-lying or poor drainage areas is possible and we will have
to watch for debris/rockslides, especially in steeper terrain.

From Friday to Sunday the continued parade of systems will mean
additional periods of precipitation, some of which will be more
moderate than others. Friday and early Saturday and then again
toward Sunday look like the wetter periods. Snow will continue in
the mountains and deeper Cascade valleys where colder air may be
trapped, especially the upper Methow. Rain or rain/snow mix will
be possible in the lowlands. Models show about 6-12 inches of snow
possible every 24 hour near the Cascade crest. The other passes
could see about 2-6 inches every 24-hours, locally higher near
Sherman Pass Friday.

Winds will be somewhat breezy Thursday to Saturday, with gusts
around 15-25 mph, locally higher over the Upper Columbia Basin and
just downwind of the Blue Mountains. Temperatures will generally
remain above normal. However looking out a little further, models
are trending closer to or slightly below normal heading toward the
end of the year and heading into January. /Solveig


&&

.AVIATION...
18Z TAFS: GEG and MWH remain in LIFR conditions. Models indicate
conditions to improve, tho it may not happen till toward 00Z for
GEG as east to southeast winds set in. Have higher confidence of
improving conditions for GEG than MWH, where the easterly winds at
MWH may reinforce the fog. Otherwise -ra will move into the region
aft 06-08Z for EAT/MWH, and 10-12Z for GEG/SFF/COE/PUW. It may
cool enough for a -rasn mix in COE.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS:
High confidence of VFR conditions for PUW/LWS/EAT. Once -ra begins
at EAT, have moderate confidence they will see deteriorating
conditions to MVFR.

-----------------------

Confidence descriptors:
Low - Less than a 30 percent chance
Moderate - 30 to 70 percent chance
High - Greater than a 70 percent chance

For additional probabilistic information for NWS Spokane airports,
please refer to the Aviation Dashboard on our webpage:
https:/www.weather.gov/otx/avndashboard

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        43  35  41  32  41  34 /  20  50 100  10  10  80
Coeur d`Alene  42  34  40  33  39  33 /  60  30 100  20  10  70
Pullman        45  36  40  31  40  34 /  30  60 100  30   0  70
Lewiston       51  40  46  35  45  38 /  20  50  90  20   0  50
Colville       40  31  39  28  36  30 /  10  40 100  10  30  90
Sandpoint      40  31  40  33  38  32 /  80  20 100  40  30  80
Kellogg        40  34  40  34  37  33 /  90  20 100  60  10  60
Moses Lake     42  37  44  29  40  35 /   0  90  60   0  20  90
Wenatchee      41  36  42  30  36  34 /   0 100  40   0  30 100
Omak           36  34  40  30  37  32 /   0  80  70   0  30 100

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&

$$