Winter Storm Warning 13, NWS Spokane, WA

771 
WWUS46 KOTX 181754
WSWOTX

URGENT - WINTER WEATHER MESSAGE
National Weather Service Spokane WA
954 AM PST Wed Dec 18 2024

WAZ048-181900-
/O.EXP.KOTX.WS.W.0013.000000T0000Z-241218T1800Z/
Western Chelan County-
Including the cities of Holden Village, Stevens Pass, and
Stehekin
954 AM PST Wed Dec 18 2024

...WINTER STORM WARNING WILL EXPIRE AT 10 AM PST THIS MORNING...

Heavy snow has come to an end. Snow showers will occur at times into 
the afternoon, but additional snow accumulations are expected to be 
minimal.

$$

WAZ049-181900-
/O.EXP.KOTX.WW.Y.0038.000000T0000Z-241218T1800Z/
Western Okanogan County-
Including the cities of Loup Loup Pass, Mazama, Twisp,
Conconully, Winthrop, and Methow
954 AM PST Wed Dec 18 2024

...WINTER WEATHER ADVISORY WILL EXPIRE AT 10 AM PST THIS MORNING...

Snow has come to an end.

$$

SVH

Area Forecast Discussion
National Weather Service Spokane WA
258 AM PST Wed Dec 18 2024

.SYNOPSIS...
The passage of a cold front today will create wind gusts as high
as 50 mph across the Palouse and Columbia Basin. The rest of the
week will feature mild temperatures and a trend of more wet
weather towards the weekend into next week.

&&

.DISCUSSION...
Today through Thursday Night:
Tricky forecast with mixed precipitation across the region.
Stevens Pass is seeing freezing rain this morning. The cold front
will push through in the next hour or two, and should transition
precip back to snow. In addition, there is a 60-70% chance of an
inch an hour snowfall briefly early this morning. Will keep the
winter storm warning going through 10am. Snow chances will
decrease after 10am.

Winthrop sensor stopped reporting at midnight, but looking at
other sensors from around the Methow Valley, temps are still below
freezing. Will keep the winter weather advisory going until 10am
as there is likely snow or freezing rain occurring.

The Okanogan Valley had freezing rain last night. Latest report
from Omak shows the temperature has warmed to 33 degrees, and
freezing rain is coming to an end. Other sensors in eastern
Okanogan county and Ferry county show temperatures have warmed in
the valleys, with light snow likely to continue above 3500 ft
through late this morning. Will let advisory expire at 4am.

Across NE WA and N ID...Sandpoint is in the process of
transitioning to rain, as seen by the airport sensor, and also a
spotter who called from the Hope area. Locations like Colville and
Bonners Ferry are still holding on to some colder air and snow
continues. Expect temperatures to warm and snow to become wet with
not much further accumulation.

Other areas like Spokane area, Palouse, LC Valley are quite mild
this morning w temps in the upper 30s to mid 40s. As the front
pushes through this morning, expect winds to increase after 6am
and continue through the morning and decrease after 1pm.
Probabilities of seeing gusts to 50 mph stands at about 30-50%
across the eastern Columbia Basin, Spokane area and Palouse. There
is an 80-90% chance of seeing gusts to 40 mph for those areas as
well as along Highway 2 west of Spokane and onto the Waterville
Plateau.

Precipitation will move out of the area this afternoon with a
quiet night of forecasting stratus and fog for the region. The
shortwave ridge will out as quickly as it moved in. Another
weather system will move in Thursday and Thursday night providing
snow for Cascades once again. Northern WA and ID mountains have a
20-30% chance of seeing some light snow above 3-4k ft. /Nisbet

Friday through Wednesday: A strengthening ridge over Central Conus
will keep the Pacific Northwest under warm Southwest flow pattern.
Several systems will push through the Inland Northwest generating
decent precip for the period. The warm air does not lead to a good
snow setup for elevations below 4000ft. The period will mainly be a
mountain snow and lowland rain. Ensembles are expecting light
mountain shower activity for Friday before a more widespread precip
event on Saturday. It will then be followed by a cold front late
Sunday, early Monday that will weaken the ridge. It will bring
another round of widespread mountain snow and lowland rain. The
Inland Northwest can expect widespread showers through the
Wednesday. Depending on the precip falling during the day or night,
lowland areas North of Hwy 2 could receive snow overnight. Isolated
pockets of freezing rain are possible in the Cascade Valleys but
probabilities of more than a trace are less than 30%. Highs for the
period will be in the 30s to low 40s. Lows will be in the 20s to low
30s. /JDC

&&

.AVIATION...
06Z TAFS: Warm frontal precipitation will clear the Spokane, Coeur
d'Alene, and Pullman airports by 08z. Once in the warm sector, low
level wind shear will increase across the southern Idaho Panhandle
and the eastern third of Washington. The mixing associated with
increasing winds should break up the low stratus until the cold
front arrives between 12-16z. Another brief period of rain will
spread across eastern Washington and north Idaho followed by gusty
west winds. Gust of 30 to 35kts are expected for KGEG, KPUW, KSFF,
and KLWS from late morning through late afternoon.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: Low confidence of
when ceilings will lift around Moses Lake and Wenatchee. The HREF
suggests enough warm sector mixing prior to 12z for improving
conditions, but it may be after cold frontal passage (15z) before
west winds disperse the low clouds and areas of fog. /GKoch

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

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        46  30  39  32  39  32 /  90   0   0  10   0   0
Coeur d'Alene  45  29  39  32  40  32 /  90   0   0  10   0   0
Pullman        46  30  41  33  42  34 /  80   0   0   0   0   0
Lewiston       56  33  45  36  47  35 /  40   0   0   0   0   0
Colville       44  24  36  30  37  29 /  90   0  10  20   0  10
Sandpoint      42  28  37  31  39  31 / 100   0  10  20   0  10
Kellogg        42  31  42  33  41  32 /  90   0   0  10   0   0
Moses Lake     49  30  43  33  41  32 /  30   0  10   0   0   0
Wenatchee      44  30  37  32  37  32 /  30   0  10  10   0   0
Omak           40  25  37  32  36  30 /  50   0  10  10   0  10

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Winter Weather Advisory until 4 AM PST early this morning for
     Northern Panhandle.

     Wind Advisory until 1 PM PST this afternoon for Coeur d'Alene
     Area-Idaho Palouse.

WA...Winter Weather Advisory until 4 AM PST early this morning for
     Central Chelan County-Northeast Mountains-Waterville
     Plateau-Wenatchee Area.

     Wind Advisory until 1 PM PST this afternoon for Lower Garfield
     and Asotin Counties-Spokane Area-Upper Columbia Basin-
     Washington Palouse-Waterville Plateau.

     Winter Storm Warning until 10 AM PST this morning for Western
     Chelan County.

     Winter Weather Advisory until 10 AM PST this morning for Western
     Okanogan County.

&&