303
FXUS66 KOTX 240143
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
543 PM PST Sat Nov 23 2024

.SYNOPSIS...
The weekend into early next week will feature seasonal
temperatures and chances for valley rain and brief snow and
periods of mountain snow.

&&

.DISCUSSION...
Minor update to account for a broader area of light showers
showing up on radar from Ephrata east into the Spokane, Coeur
d`Alene, and Kellogg areas. The update was mainly to extend the
chance of showers for west across the Upper Columbia Basin and
Moses Lake area. These are associated with a weak mid level wave
tracking across the region. JW

&&

.AVIATION...
18Z TAFS: Other than some stubborn stratus creating MVFR cigs at
SFF/COE...VFR conditions prevail. Both the HREF and NBM have very
low probabilities of fog/stratus overnight for the TAF locations.
Have tried to simplify the TAFs and show more optimistic
conditions. Winds will become easterly after 14Z, which will bring
improving cigs to the TAFs. The one caveat is EAT where the light
upslope winds will lower cigs and bring a threat of -ra aft 16Z.
Other locations in the east slopes of the Cascades will likely see
snow beginning after 13Z.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS:
With the moist boundary layer, MVFR/IFR fog and stratus is always
possible, even if the model guidance says otherwise.

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

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

&&

.PREV DISCUSSION... /issued 357 PM PST Sat Nov 23 2024/

Tonight through Monday Night: The weather disturbance that
brought widespread rain to portions of eastern WA and the ID
Panhandle overnight and this morning has weakened and moved into
western MT. Currently there are some widely scattered showers
producing light rain. That will continue this evening and
overnight, mainly for extreme eastern WA and north ID. Snow levels
will lower down to 2k-2500 ft overnight across northern WA and
ID. The Methow valley has been under the fog/stratus all day, and
has not warmed above 33. They will be able to cool a degree or
two, so that by morning when precip begins in the Cascades, it
should fall as snow.

As the low off the coast migrates south tonight and Sunday,
another disturbance will move into the region. The winds will
become upslope into the east slopes of the Cascades, providing
snow beginning Sunday morning. Light snow will continue through
the day and into Monday morning. Accumulations look to be light.
There is up to a half an inch for Leavenworth/Plain with no snow
accumulation expected for Wenatchee. The Methow Valley is
forecast to receive 2-3 inches. As you head into the
mountains...Stevens Pass has a 60% chance of receiving 4 inches
and a 30% chance of 8 inches. Loup Loup and Sherman Pass have 3 to
5 inches of snow in the forecast for Sunday through Monday
morning.

Precip chances spread eastward Sunday night and Monday. Across
the northern WA/ID valleys snow accumulation looks to be a half
inch or less, with light amounts in the mountains.

Temperatures will be at or a few degrees above average through the
period. This equates to mid 20s to low 30s for overnight lows and
mid 30s to mid 40s for highs. /Nisbet

Tuesday through Saturday: The upper-level low currently planted
offshore will track to the southeast and move inland along the
Oregon/California border come Tuesday. Heading into the middle of
the week, we`ll transition into a cool northwesterly flow regime as
a ridge of high pressure amplifies off of the coast, and
precipitation chances will be mainly focused over the Cascades,
Idaho panhandle, and the eastern third of Washington. Temperatures
will gradually trend colder through the period with afternoon highs
starting out near 40 on Tuesday and dropping into the low to mid 30s
by the end of the week. Lows Tuesday night into Wednesday morning
will range from the mid 20s to mid 30s and will drop by a couple of
degrees each day through the end of the week, dipping into the teens
to low 20s overnight Friday into Saturday. The latest ensemble runs
have come into better agreement on where the ridge axis will set up
and whether the Inland Northwest will see precipitation from any
shortwaves that drop down the east side of the ridge. Nearly all
ensemble members are showing the ridge axis staying far enough
offshore that the Cascades, Idaho panhandle, and eastern third of
Washington will see at least some intermittent precipitation from
weak shortwaves dropping out of the northwest, though amounts look
light and non-impactful at this time. /Fewkes

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        32  41  31  43  32  40 /  60  20  20  40  20  30
Coeur d`Alene  33  41  29  41  32  39 /  70  20  20  60  30  60
Pullman        32  42  31  42  31  38 /  40  10  10  30  40  60
Lewiston       33  45  31  47  36  44 /  30  10  10  10  20  40
Colville       31  38  28  38  25  39 /  10  20  40  60  30  20
Sandpoint      30  36  27  37  30  41 /  60  40  30  80  60  60
Kellogg        33  39  25  39  32  38 /  60  30  20  70  50  80
Moses Lake     32  42  35  44  31  43 /  20  20  30  20  10  10
Wenatchee      30  37  31  41  32  43 /   0  60  50  20  10  10
Omak           30  38  34  39  29  38 /   0  60  60  20  10   0

&&

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

$$