367
FXUS66 KOTX 072350
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
341 PM PST Fri Feb 7 2025

.SYNOPSIS...
Next round of light snow moves into extreme southeast WA and the
southern ID Panhandle early this morning. More widespread snow
showers are forecast for Saturday. Temperatures will remain below
average through the weekend into next week. Modified Arctic air
will move in across the region early next week bringing a period
of very cold air. Many places will see single digit temperatures
by Tuesday and Wednesday with some locations potentially dipping
below zero.

&&

.DISCUSSION...
Today and tomorrow: Much of the region has cleared out today in
between two systems. Light snow has continued in southeast
Washington and the southern Panhandle today as a weak vort max
continues to traverse east in south central Washington and Oregon.
The sun will disappear tomorrow as I am anticipating low stratus
to develop tonight in the Columbia Basin and Palouse and move
towards Spokane. Flow will turn northwesterly tonight and into
tomorrow as a shortwave approaches the INW from southern BC. This
will bring a fresh swath of snow with the greatest amounts in
southeast Washington and the central/southern ID Panhandle (1-4).
500 mb temperatures are quite cold around -35 to -37C as this wave
of precip moves so some snow bands may be intense. Snow ratios
will be high (15:1 to 20:1) and 25 kt westerly boundary layer
winds may cause some blowing snow issues on roadways tomorrow
afternoon and night, especially US-195 from Rosalia to Uniontown
and US-95 south of Cda. /DB

Sunday through Friday: After the passage of shortwave troughs
through the area, cold arctic air will begin flowing into the
northwestern US due to the ridge over Alaska strengthening. This
will bring colder air into the forecast area and drop temperatures
down nearly 10 to 15 degrees below normal for this time of year.
This cooling will start on Sunday and be at its coldest on
Tuesday. High temperatures values on Tuesday range from the high
teens to the low 20s. Low temperatures through the more sheltered
valleys have a chance at dropping below zero. In particular, the
Deer Park, Coeur d`Alene, Pullman, and Lewiston areas have a 40
percent chance or greater of seeing low temperatures below zero
degrees. Wind chill values below zero will be more widespread
through eastern Washington and the Idaho panhandle. Should the
forecast continue to trend in this direction, the first Cold Weather
Advisory of the year could be issued. While model ensemble guidance
is shaky by this point, trends are pointing towards a low pressure
system in eastern Canada dropping heights and allowing temperatures
to warm back up, though they will still be below normal through the
extended forecast period. The northerly flow providing our cold
temperatures will also bring a chance of elevated winds Monday
afternoon into Tuesday morning as well. The Okanogan Valley,
Waterville Plateau, and upper Columbia Basin are expected to see
sustained winds reach up to 20 mph, with wind gusts up to 30 mph in
isolated areas. Winds in the northern Idaho panhandle will also be
elevated during these same times. Guidance near the end of the
extended period brings another chance for snow showers. This agrees
with the 6-10 Day Precipitation Outlook issued by the CPC, which has
our forecast area seeing a 50 to 70 percent chance of seeing above
normal precipitation. /AS

&&

.AVIATION...
00Z TAFS: Low stratus will develop tonight at KGEG-KSFF-KCOE-
KPUW-KMWH and will be capable of producing light snow. Stronger
snow showers will develop around 20z Saturday in the KGEG-KPUW
vicinity capable of producing IFR visibility restrictions.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: There is a 30%
chance of fog development for KGEG around but the pattern looks to
favor low stratus instead.

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

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

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        15  29  15  27  11  25 /   0  30  20   0  10   0
Coeur d`Alene  12  30  16  29  11  25 /   0  30  30  10  10  10
Pullman        15  29  21  28  16  24 /   0  40  70  30  20  20
Lewiston       18  34  25  35  21  29 /   0  20  50  20  20  10
Colville       10  29   5  28   4  25 /   0  10   0   0   0   0
Sandpoint      13  28  16  27  13  23 /   0  50  20  10  10  10
Kellogg        15  29  21  28  13  21 /   0  60  50  20  20  20
Moses Lake     19  32  16  32  16  30 /   0  10   0   0   0   0
Wenatchee      17  29  16  29  16  25 /   0  10   0   0   0   0
Omak           12  28  10  28   9  26 /   0  10   0   0   0   0

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Winter Weather Advisory from 1 PM Saturday to 4 AM PST Sunday
     for Central Panhandle Mountains-Idaho Palouse-Lewis and
     Southern Nez Perce Counties-Lewiston Area.

WA...Winter Weather Advisory from 1 PM Saturday to 4 AM PST Sunday
     for Washington Palouse.

&&

$$