Sunset Hill, Washington Weather Forecast Discussion

729
FXUS66 KOTX 260542
AFDOTX
Area Forecast Discussion
National Weather Service Spokane WA
1042 PM PDT Thu Sep 25 2025
.KEY MESSAGES...
- Vigorous dry cold front passage Thursday afternoon/evening
  with windy and dry conditions resulting in critical fire
  weather conditions.
- Winds may also produce blowing dust across the Waterville
  Plateau into the Columbia Basin Thursday afternoon.
- Patchy frost for northern mountain valleys and northern
  Panhandle overnight Thursday and Friday.
&&
.SYNOPSIS...
Windy conditions and very low RHs are expected with a cold
front passage late Thursday afternoon and evening. The
combination of gusty winds and dry conditions will lead to
critical fire weather conditions across much of central and
eastern Washington. Chilly mornings Friday and Saturday before
temperatures see a bump up above normal over the weekend. Cooler
temperatures and chances for showers by early next week.
&&
.DISCUSSION...
Thursday: A fast-moving cold front and associated trough is pushing
into western Washington early this afternoon and will continue
swiftly east through the Inland Northwest later this afternoon and
evening. This system will bring dry and gusty westerly winds. Ahead
of the front, southwest winds are already increasing with relative
humidity values in the low teens across central Washington. The
strongest winds are expected in the lee of the Cascades as the
front moves through with winds decreasing though remaining
gusty across the Columbia Basin, and extending into the Spokane
area and Palouse. As of 12 PM, the PDX-GEG pressure gradient was
+8 mb, with values projected to rise to +11-12 mb. This will
support sustained winds of 15-30 mph with gusts of 30-45 mph
late this afternoon into the evening. A few light showers (15%
chance) will be possible over the northern mountains with the
frontal passage, but otherwise this will be a dry front with
PWATs dropping to 0.30-0.40 inches as much drier air aloft mixes
to the surface. The main impacts will be rapid fire spread
potential with any new starts and areas of blowing dust near
recently plowed fields.
A secondary concern will develop this evening into the early
overnight hours across the Cascades and east slopes as a
northwest- to- southeast oriented jet streak shifts into
Washington behind the upper trough. Strong westerly flow over
the terrain combined with a stable layer near ridge tops will
favor mountain wave activity. While an overnight surface
inversion will keep lower valley winds lighter, exposed ridges
may experience continued gusty winds tonight.
Friday through Wednesday: Broad zonal flow will set up across the
Pacific Northwest on Friday following the cold frontal passage. Dry
air and clearing skies Thursday night into Friday will allow for a
chilly start Friday morning, with afternoon highs 5-10 degrees
cooler than Thursday (upper 60s to mid-70s). Over the weekend, the
Inland Northwest will sit on the western side of an amplifying ridge
over the central US in response to a deepening trough over the
eastern Pacific and a low moving into the Gulf of Alaska.
Temperatures will rebound into the upper 70s to 80s through Sunday.
From Sunday night into midweek, ensemble guidance is in general
agreement that the leading upper-level trough will move onshore
the PNW, followed by a weaker version of the Gulf of Alaska
low. Forecast confidence is high that temperatures will cool
with increasing precipitation chances across the Inland
Northwest. Between 5 AM Monday and 5 AM Thursday, there is a
>70% chance of at least 0.25 inches of precipitation across the
Cascades, northern mountains, Idaho Panhandle mountains, and
Camas Prairie. Probabilities are 50- 70% for the northern
Washington and Idaho Panhandle valleys, Spokane area, Palouse,
and L-C Valley, decreasing to 15-30% over the Columbia Basin,
Waterville Plateau, and near Wenatchee. For the larch marchers,
NBM guidance also supports snow levels lowering to 6500-7000
feet over the Cascades Monday night through Wednesday, which
could bring snow to the higher peaks. Stay tuned! /vmt
&&
.AVIATION...
06Z TAFS: A cold front has swept through the region and winds
remain gusty along the East Slopes of the Cascades and across
portions of the Columbia Basin and Palouse. Wind gusts will
slowly come down over the next 2-5 hours for most terminals
but strong gusts are expected to remain in place through
the night over the higher terrain of the East Slopes.
On Friday, winds will begin to shift direction from west and
northwest back to the southwest. Gusts up to 20 mph are
anticipated for much of Northeastern WA and North Idaho between
19-00z.
Fires in the Cascades are very active and will continue to
produce heavy smoke downstream. KEAT, KMWH, and KEPH carry
the highest probabilities for vis restrictions overnight though
would not rule out brief periods of 5-6SM around LWS, PUW, GEG,
and COE. Heading into Friday afternoon and evening, smoke
transport will shift the focus for smoke between EAT and OMK.
FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS:
High confidence for breezy winds through 09z and across the
Cascades peaks through the night. Moderate to high confidence
for gusts around 20 mph for COE, DEW, GEG Friday afternoon.
Confidence is low for exact visibility restrictions at any given
airport given recent trends in observations. KEAT is the
exception with moderate confidence for restrictions given its
proximity to the fires. /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:/weather.gov/otx/avndashboard
&&
.Preliminary Point Temps/PoPs...
Spokane        44  69  46  76  50  82 /   0   0   0   0   0   0
Coeur d`Alene  45  69  45  75  50  82 /   0   0   0   0   0   0
Pullman        41  66  42  76  48  79 /   0   0   0   0   0   0
Lewiston       51  72  49  81  54  84 /   0   0   0   0   0   0
Colville       35  71  37  73  38  78 /  10   0   0   0   0   0
Sandpoint      41  67  40  71  45  78 /  10   0   0   0   0   0
Kellogg        46  66  47  77  55  81 /   0   0   0   0   0   0
Moses Lake     42  73  45  77  46  79 /  10   0   0   0   0   0
Wenatchee      51  74  54  77  55  78 /  10   0   0   0   0   0
Omak           43  73  50  76  50  78 /  10   0   0   0   0   0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
WA...Red Flag Warning until 11 PM PDT this evening for Colville
     Reservation (Zone 702)-East Portion of North Cascades
     National Park/Lake Chelan National Recreation Area (Zone
     697)-East Washington North Cascades (Zone 698)-Eastern
     Columbia Basin  -Palouse  -Spokane Area (Zone 708)-
     Foothills of Central Washington Cascades (Zone 705)-Lower
     Palouse  -Snake River (Zone 709)-Methow Valley (Zone 704)-
     Okanogan Valley (Zone 703)-Waterville Plateau (Zone 706)-
     Western Columbia Basin (Zone 707).
     Air Quality Alert until noon PDT Friday for Central Chelan
     County-Okanogan Highlands-Okanogan Valley-Waterville
     Plateau-Wenatchee Area-Western Chelan County-Western
     Okanogan County.
     Red Flag Warning until 9 AM PDT Friday for East Washington
     Central Cascades (Zone 696).
ID...None.
&&
$$

NWS OTX Office Area Forecast Discussion