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000
FXUS66 KOTX 280454
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
954 PM PDT Sat Apr 27 2024

.SYNOPSIS...
The remainder of the weekend and early next week will feature
showery weather over the mountains with seasonal like
temperatures. Sunday and Monday have the potential to be windy
with the passage of a frontal system. This system will also bring
snow to the Cascade mountain passes Sunday night and Monday
morning. Temperatures begin to warm mid next week onward, but
showers remain in the forecast as well.

&&

.DISCUSSION...
Tonight through Monday Night: Trough moving through the region is
producing scattered rain showers with a few lightning strikes this
afternoon. The cores are very small, with brief heavy rain
possible under the tiny cores and some graupel. The main area is
northeast WA and the ID Panhandle. These showers will continue to
move northeast through the afternoon and evening hours. Showers
will diminish after sunset, however isolated showers will be
possible through the night with the trough exiting.

Sunday a stronger trough approaches the area with showers again.
Instability isn`t as good Sunday, and only have mention of a
15% chance of thunderstorms for northern Pend Oreille county and
the north ID Panhandle Sandpoint area northward in the afternoon.

South to southwest winds will increase Sunday afternoon with over
a 90% chance of sustained winds over 20 mph across areas south of
Omak onto the Waterville Plateau and a 50% chance across portions
of the Columbia Basin and onto the West Plains and western Palouse.
There is about a 10% chance of blowing dust in the Columbia Basin.
Confidence is low and therefore do not have it mentioned in the
forecast at this time.

As the trough moves onshore Sunday night snow levels will begin
to lower. There is a 90% chance of 3 inches of snow over Stevens
Pass Sunday night and Monday morning and a 50% chance of 5 inches.
Have decided to issue a winter weather advisory above 3500 feet
for Stevens Pass and the Holden Village area. Snow will start
during the evening but begin to accumulate a couple hours after
sunset. The HREF only goes till 12Z Monday, but at 12Z Monday
(5am) it is showing a 40% chance of an inch an hour over Stevens
Pass. By mid to late morning, it will become more difficult for
snow to accumulate on the roads given the sun angle and spring
time temps. Snow will continue to fall through Monday night,
though accumulations on roads will be minor.

Southwest to west winds pick up again on Monday. The same area
mentioned above will see high probabilities of sustain wind speeds
20 mph or greater, and gusts to 30 mph. Given stronger gusts
Monday compared to Sunday where dust tends to form, have kept the
patchy blowing dust mentioned across portions of the Columbia
Basin.

The trough moves into the region Monday afternoon which will bring
more widespread showers. Colder 500 mb temps will create enough
instability for a 20% chance of thunderstorms for most of eastern
Washington and the ID Panhandle. Given the stronger westerly winds
have shadowed out the Wenatchee and Moses Lake area in the
afternoon. /Nisbet

Tuesday through Friday: Tuesday will be another day of unsettled
conditions with showers and isolated thunderstorms over the
Cascades, ID Panhandle, and far eastern WA. Winds will decrease
through the day on Tuesday from what they were on Monday, but will
still be a bit breezy with gusts of 20 to 25 mph.

Most of the region will see temperatures drop near freezing Tuesday
night, and a few locations in the mountain valleys and the northern
Basin may drop below freezing. Wednesday will be similar to Tuesday
with showers and breezy afternoon winds, though the showers on
Wednesday will be more limited to the Cascade Crest and mountains of
Shoshone County.

Heading into the second half of the week, we start to see
significant divergence in model solutions. Around 60 percent of
models suggest a ridge will move in, taking the place of the trough
that will be over us through the first half of the week, and warming
our temperatures back into the 60s by next weekend. The other 40
percent of ensemble members want to keep us in a troughing pattern,
which would result in temperatures staying in the 50s through the
end of the week. /Fewkes

&&

.AVIATION...
06Z TAFS: Showers have decreased this evening, with any remaining
precip generally limited to far northern ID. Chances for showers
increase again after 15Z Sunday. Winds pick up after sunrise
Sunday morning and become gusty after 22Z for most TAF locations.


FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS:
There is a threat again for scattered to broken MVFR stratus
developing Sunday morning 12-18Z between Pullman and Spokane. This
comes with low confidence to impact the terminals but is certainly
something to monitor.

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

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        39  58  39  51  33  53 /  40  20  10  70  10  20
Coeur d`Alene  40  54  38  47  31  50 /  40  50  40  90  20  30
Pullman        39  55  37  48  31  50 /  10  20  30  80  30  50
Lewiston       44  64  44  55  37  57 /  10  10  30  70  20  30
Colville       33  58  34  51  26  52 /  70  30  30  80  20  30
Sandpoint      40  52  38  47  32  47 /  80  70  60  90  40  60
Kellogg        42  51  39  44  33  45 /  40  70  60  90  50  70
Moses Lake     39  63  39  59  34  60 /   0  10   0  20   0  10
Wenatchee      42  60  40  55  37  57 /  10  10  10  20   0  10
Omak           39  63  37  57  32  60 /  10  10  10  30   0  10

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Winter Weather Advisory from 11 PM Sunday to 11 AM PDT Monday
     for Western Chelan County.

&&

$$