451
FXUS66 KOTX 081831
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
1031 AM PST Fri Nov 8 2024

.SYNOPSIS...
Dry and quiet weather is forecast through Saturday afternoon as
high pressure remains over the area. A weak weather system
arrives over the weekend bringing a chance of light rain and
mountain snow. Unsettled weather will continue through next week
with periods of mountain snow and lowland rain. Snow over mountain
passes may be moderate to heavy at times with winter travel
possible.

&&

.DISCUSSION...
Friday through Saturday afternoon: Dry conditions and quiet weather
will prevail across the Inland Northwest through Saturday afternoon
while we remain under the influence of weak upper-level ridging.
Warm, southwesterly flow aloft will create a strong inversion Friday
night into Saturday morning which will be favorable for fog
formation along rivers, lakes, and in the more sheltered valleys of
northern WA and the ID panhandle. In addition to allowing fog to
form, the strong inversion will trap smoke from numerous prescribed
and pile burns across northern ID near the surface, so those located
in the ID panhandle as well as near the WA-ID border may notice a
haze in the air especially in the early morning hours on Saturday.
Daytime highs Friday and Saturday will be mild in the upper 40s to
mid 50s.

Saturday evening through Sunday morning: An unsettled pattern
returns with the first of a series of systems on track to move in
late Saturday. This first system will be the weakest in the series,
allowing us to ease back into an active weather pattern. Snow levels
will start out above 5000 feet Saturday evening and will drop to
4500 feet by early Sunday morning for the North Cascades and the
higher terrain along the WA-British Columbia border, thus
precipitation will start out in the form of rain but will likely
transition to a mix of rain and snow over Washington Pass by Sunday
morning. Precip at lower elevation passes including Stevens and
Lookout will stay as rain through this first system. Lowlands just
east of the Cascades and in the lower Columbia Basin including
Conconully, Wenatchee, Moses Lake, Ritzville, and Pullman will be in
the rain shadow of the Cascades and only have around a 30 percent
chance of seeing measurable precipitation with this first system.
Chances for measurable rainfall get higher further east of the
Cascades toward Colville, Spokane, and into the ID panhandle. /Fewkes

Sunday through Thursday: An active weather pattern is in store as
a series of weather systems passing through the area. A mild tap
of southwest winds ahead of each system will help keep low
temperatures above freezing for most valley locations supporting
rain as the precipitation type. Snow levels start off between
5000-6500 feet Sunday and Monday, then down to 3500-4500 feet on
Tuesday into Wednesday AM, before rising again to 4000-5500 feet
Wednesday PM and Thursday. Timing of the first system arrives
Sunday Night into Monday, followed by post-frontal showers Monday
Night into Tuesday, before the next system arrives Wednesday into
Thursday. Expect valley rain and mountain snow with each system.
Below the probabilities from the National Blend of Models (NBM) of
various snow thresholds being reaches for the two storms

Storm 1: Sunday Night through Tuesday: Chances for 2+, 6+, 12+"
Washington: 100%, 100%, 70%
Stevens: 80%, 50%, 30%,
Sherman: 50%, 5%, 0%
Lookout: 60%, 20%, 5%

Storm 2: TUE Night - Thursday: Chances for 2+, 6+, 12+, 18+"
Washington: 100%, 100%, 100%, 70%
Stevens: 100%, 50%, 25%, 10%
Sherman: 95%, 60%, 10%, 0%
Lookout: 90%, 70%, 10%, 0%

JW

&&

.AVIATION...
18Z TAFS: There will be a gradual increase in high level clouds
across the Inland Northwest as bands of cirrus clouds spread over
the northern periphery of an upper level high pressure ridge.
Strong low level stability will trap smoke near the surface over
north Idaho and across eastern Washington. Visibility reductions
from smoke will be up to 5 miles.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS:
Low to moderate confidence is visibility reductions due to haze.

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

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        50  37  51  36  50  44 /   0   0  10  40  40  80
Coeur d`Alene  50  33  51  38  49  41 /   0   0  10  70  50  80
Pullman        54  36  52  38  51  42 /   0   0   0  50  40  70
Lewiston       54  37  57  43  58  45 /   0   0   0  30  20  50
Colville       48  31  48  34  45  39 /   0   0  20  60  50  90
Sandpoint      45  31  49  38  45  39 /   0   0  20  70  60  90
Kellogg        51  32  53  37  47  39 /   0   0   0  80  60  70
Moses Lake     52  29  49  32  50  43 /   0   0  10  20  20  80
Wenatchee      48  34  50  36  49  39 /   0   0  20  20  20  90
Omak           48  34  51  35  50  40 /   0   0  30  20  20  90

&&

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

$$