Lewiston, Idaho 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

108
FXUS66 KOTX 222354
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
354 PM PST Mon Dec 22 2025

.KEY MESSAGES...

- Periods of rain and snow through the week with high degree of
  uncertainty in forecast specifics.
- Chance for breezy to gusty winds 20-25 mph for the basin area
  Wednesday morning through afternoon.

&&

.SYNOPSIS...
The Inland Northwest will remain in an active pattern through
the week, with several opportunities for impactful mountain
snow, light lowland rain and snow, and breezy winds.

&&

.DISCUSSION...
Today through Tuesday: An upper level low pressure system sitting
off the western Canadian and PNW coast will move northeastward
through the day. This will result in mostly orographically enhanced
snow along the Cascades and Northern Mountains. Totals are not
expected to be particularly impactful: NBM probabilities indicate
the highest elevations of the Cascades have only a 10-20% chance of
seeing 6 or more inches of snow. Other lowland areas will see a
break from precipitation for the next day. Temperatures
throughout the lowlands continue to be warmer than normal, with
highs in the low 40s 7-10 degrees warmer than normal for this
time of year.

Tuesday night through Thursday: The low pressure system will
strengthen as it moves southward down the Pacific Coast. PWATs
rise to 150-200% of normal and will bring widespread
precipitation to the area. For the lowlands, since snow levels
will be very high (3000-4000 feet) with this storm, this
precipitation will fall as rain. Chances for a wetting rain
(0.10 inches or more) are 50-70% for the Spokane/Coeur d`Alene
and Columbia Basin areas. Those chances drop to 10-20% when
looking at probabilities of a quarter inch or more, so the
rainfall range is looking like 0.1-0.25 inches, much of which
will fall Tuesday evening through Wednesday evening. The
northern Cascades have a 50-70% chance of 6 inches or more of
snow.

Something else to keep an eye on will be wind gusts Wednesday
morning through afternoon as a surface high dropping into Alberta
creates a tightened pressure gradient. Current model runs show
potential wind gusts to 25-30mph with some isolated gusts up to
40 mph throughout the Basin and Palouse areas. The spread in
wind gusts among models at the moment is very high, with some
ensembles such as the ECMWF and GEFS not favoring gusty winds
at all, but other medium range models such as the NAM favoring
the higher wind gusts. While these winds are not anticipated to
reach regionwide advisory levels, since Christmas Eve is a big
travel holiday there could be some minor impacts to drivers,
especially in high profile vehicles.

Thursday evening through Monday: A second round of precipitation
will move through Christmas evening through early Saturday morning.
Main forcing for this is the low weakening and moving
northeastward, with a trough passing over the state of
Washington. 850mb temperatures will start above 0C on Thursday
with snow levels around 3000-4000 feet, favoring precipitation
starting in the lowlands as rain. As colder air is ushered in
by the low, these snow levels will drop to 1000-2000 feet and
850mb temperatures will drop to -5C. This will result in a
period of mixed precipitation as rain transitions to snow.
Current precipitation probabilities show a 65% chance and above
for 0.1 inches of rain. Snow accumulation in the lowlands will
be very low, with totals less than an inch expected. Alongside the
Cascades, the Northern Mountains and the Northern Idaho
Panhandle Mountains have a 70% chance or higher of seeing 6
inches or more of snow at the highest elevations.

For the rest of the weekend, a ridge will begin building off the PNW
coast, bringing a break from precipitation. While clusters for QPF
are in good agreement for a drier weekend, they diverge next
week as long range models show the strengthening ridge ushering
in higher PWATs. The CPC`s 6-10 and 8-14 Day Outlooks continue
to show increased chances for above average precipitation across
the forecast area. Bottom line, expect a continued string of
active weather next week, continued wintry conditions along
mountain passes, and stay tuned in case the chance for travel
impacts increase for the New Years holiday. /AS

&&

.AVIATION...
00Z TAFs: VFR conditions will slowly degrade in the evening for
most sites, except KEAT which is already degraded. How low cigs
get is a low confidence forecast. Showers will impact KPUW-
KGEG-KSFF-KCOE through 6z this evening. More rain will approach
SE WA Tuesday morning and spread northward through the day.

.FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: Low confidence
for coverage of IFR cigs tonight.

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

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        31  41  34  41  32  44 /  20  10  70  80  20  50
Coeur d`Alene  32  41  35  43  34  45 /  30  20  70  80  30  50
Pullman        32  40  37  44  35  46 /  10  50  50  50  30  40
Lewiston       36  42  38  50  39  50 /  10  50  20  20  20  10
Colville       28  39  30  37  30  40 /  50  10  70 100  30  60
Sandpoint      31  39  34  39  33  41 /  50  20  90 100  50  60
Kellogg        33  40  36  43  36  45 /  40  40  80  80  50  60
Moses Lake     29  40  33  43  31  42 /  10  10  80  60  10  40
Wenatchee      29  36  31  39  30  35 /  30   0  70  80  10  50
Omak           27  35  31  37  30  35 /  60   0  60  90  10  40

&&

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

&&

$$