Lewiston, Idaho 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

666
FXUS66 KOTX 222350
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
350 PM PST Sun Feb 22 2026

.KEY MESSAGES...

- Winter travel conditions expected across mountain passes this
  week.

- Trending warmer and wetter this week, with lowland rain and
  mountain snow.

- Moderate rains for the Palouse leading to rises on rivers,
  creeks, and stream along with ponding of water in fields.

- Gusty winds late Tuesday to Thursday.

&&

.SYNOPSIS...
Travel over the Cascades could be challenging tonight into
tomorrow morning as a system moves through, impacting the
Monday morning commute. Due to moderating temperatures, snow
will be limited to the mountains and the lowlands will see rain.
The weather continues to be unsettled through the week, bringing
continued rounds mountain snow and lowland rain. Chances are
increasing for strong wind gusts Wednesday through Thursday.

&&

.DISCUSSION...
Tonight-Monday: Moisture is being directed into the Inland NW ahead
of a deep low pressure system spinning off the WA Coast. Most
communities across E WA and N Idaho are experiencing increasing
cloud cover but continued dry conditions. Light precipitation in
the form of wet snow is falling over the Cascades and at times,
western Columbia Basin and Okanogan Valley though impacts have
been minimal due to temperatures above freezing. The influx of
moisture will result in moderating dewpoints and ultimately
rising snow levels through this evening. A shortwave ejecting
from the offshore low will track into southern BC overnight
ushering a frontal boundary into the region with precipitation
expanding eastward. The front will struggle to make it south of
I-90 by Monday morning with continued dry conditions for the
lower Idaho Panhandle, Palouse, and southern Basin. This will
change heading into Monday morning as yet another midlevel wave
ejects inland across southern BC pressing the stalled frontal
boundary southward. Precipitation will taper off across north-
central WA and ramp up across the Idaho Panhandle and areas of E
WA. Precipitable water values along the boundary will increase
near 0.70" or 180% of normal. During this time, midlevel flow
will be shifting from the south to southwest to west with a bulk
of the moisture squeezed out over the Cascade Crest and Idaho
Panhandle where we find 60-80% chances for QPF in excess of
.50". This will not be a very progressive front, especially when
sagging south through Palouse which is where models indicate
50-60% chances for rainfall amounts of 0.50" or more. Impacts
for this period include winter travel conditions across the
mountain passes (Cascades, Sherman, and Lookout) and increased
flows on the rivers and streams across the Palouse and lower
Idaho Panhandle. At this time, the threat for flooding is
extremely low. Flashier creeks like Paradise Creek will need to
be monitored with current forecast just shy of bankfull. Snow
melt is contributing to these rises. On the mountain passes,
impactful snow and snow rates are expected on the Cascades
Sunday night into Monday morning; then late Monday afternoon
into Monday night for Lookout Pass. An alternate scenario as
indicated by the NAM is for snow levels to lower further Monday
night into Tuesday with snow reaching down to 3000 feet. HREF is
picking up on this with 20-40% chance for light snow
accumulations Monday for locations like Pullman, St Maries, and
Deary. In this scenario, there would less runoff and concerns
for any hydro issues.

Tuesday-Thursday: Weather impacts for this period will remain ongoing
precipitation across southern WA/north-central WA, gusty winds,
and continued mountain snow showers. Swift west to northwest
flow will develop as additional shortwave energy tracks along
the Canadian border. There will be a noticeable increase in
winds late Tuesday and overnight with a good signal for cold
advection and strong packing of pressure gradients. The ensemble
means from the GEFS/ENS are good agreement of a 13 mb Portland
to Kalispel pressure gradient though a few members are as high
as 15-19mb and low as 8-12 mb. There is a moderate to high
chance (40-60%) for gusts at least 30 mph and 10-20% chance for
gusts of 40 mph or stronger. A second surge of winds arrives
late Wednesday into Thursday. This one is not as clear cut with
GEFS members on the lower side vs the ENS members. We have seen
many of the ENS members trend lower with the last two runs (very
little showing gusts > 50 mph now) which is great news for
reducing wind impacts. Nonetheless, probabilities (55-75%) are
higher on a more expansive scale for gusts > 30 mph (55-75%) and
still 20-40% for gusts > 40 mph. If these trends continue,
thinking this event will result in widespread 30-40 mph with
isolated gusts around 45 mph but we continue to monitor this
closely for the low probability, stronger outcomes.

There are differences with the depth and track of the low on Tuesday
which is having large ramifications on amount of additional
rain and mountain snow Tuesday. If the system takes a slightly
more northward track, moderate precipitation will remain over
southern WA and north-central WA Tuesday leading to additional
rises on rivers, creeks, and streams in these areas. The threat
for nuisance field flooding and rock slides also increases. Snow
amounts in the Cascades and Idaho Panhandle mountains would
also be higher. If the system takes a slightly southern track,
the deeper moisture will reside south of the forecast area with
mainly light, persistent mountain snow showers. This mainly
impacts Tuesday as there is moderate to high confidence for a
cold front Tuesday night to usher the axis of deeper moisture to
the south by Wednesday morning.


Friday-Sunday: The region will remain under broad northwest flow
aloft delivering near to cooler than normal temperatures and
breezy conditions. Not seeing any signals for any significant
weather impacts at this time. Roughly a 50% chance for mountain
snow showers each day with little to no precipitation in the lee
of the Cascades and into the Columbia Basin. /sb

&&

.AVIATION...
00Z TAFS: Moisture continues to stream into the region with a
slow saturation. Areas of light rain and mountain snow tonight
mainly for terminals along and north of I-90. HREF comes with a
50% chance for cigs to lower below 3000 feet which increases
near 60% Monday AM with the arrival of a weak cold front and
shift of winds. Ahead of this front, east winds will be in
leading to low-level wind shear for PUW and marginal LLWS for
COE-SFF-GEG. Once winds shift to the southwest, gusts to 20 mph
expected across the eastern Columbia Basin.


FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS:
There is moderate uncertainty with timing of MVFR cigs given
wide ranges in precipitaiton duration and timing. This is
evident in the HREF probabilities near 50% for cigs below 3000
feet across all terminals along and north of I-90. Alternate
scenario for Monday morning is around MWH-EAT which could have
breaks in the clouds and potential for broken low stratus.
Confidence is not high to keep this prevailing and opted for
scattered coverage.  /sb

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

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        38  45  35  42  30  44 /  90  90  50  50  50  20
Coeur d`Alene  36  44  34  41  30  42 /  90  90  60  60  70  40
Pullman        36  46  37  43  33  43 /  50  90  90  80  80  40
Lewiston       40  52  41  47  38  50 /  50  80  90  80  80  30
Colville       33  43  27  42  25  42 /  90  80  20  40  40  20
Sandpoint      35  41  32  38  29  40 /  90 100  60  60  70  60
Kellogg        39  42  35  41  33  39 /  80 100  80  70  80  70
Moses Lake     37  47  33  46  29  50 /  60  60  40  50  20   0
Wenatchee      34  44  32  43  30  45 /  80  80  30  50  30  10
Omak           35  44  29  42  28  44 /  80  60  10  30  20  10

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
WA...Winter Weather Advisory from 10 PM this evening to 1 PM PST
     Monday for Western Chelan County.
ID...Winter Weather Advisory from noon Monday to 8 AM PST Tuesday
     for Central Panhandle Mountains.

&&

$$