Keller, Washington Weather Forecast Discussion

152
FXUS66 KOTX 210736
AFDOTX
Area Forecast Discussion
National Weather Service Spokane WA
1236 AM PDT Sun Sep 21 2025
.KEY MESSAGES...
- Sunday cold front to deliver cooler temperatures, windy
  conditions, and chances for light showers.
- Another ridge forms Monday into Tuesday, with temperatures
  warming back into the 80s by Wednesday.
&&
.SYNOPSIS...
Warm, breezy weather will continue Saturday, with elevated fire
weather conditions for portions of the area. Sunday, a front
brings cooler temperatures, chances for showers, and gusty winds
and a chance for thunderstorms. Chilly overnight lows expected
Sunday night and Monday night. Temperatures warm again under a
ridge of high pressure Tuesday and Wednesday.
&&
.DISCUSSION...
Today through tonight: A low pressure sitting off the Canadian coast
will move eastward and into the area tomorrow will usher in a cold
front, bringing a change in weather pattern to the region. The front
will begin moving through the area early this morning and moving
east of the state by late afternoon. Currently, CAMs are showing
some light precipitation over southeast Washington and the Idaho
Panhandle ahead of the front due to some embedded shortwaves in the
flow interacting with the incoming moisture, but amounts will be
very light. The CAMs are showing some convection with these showers
as a couple small areas of vorticity move in with the rain, even
though CAPE values are near zero. After the cold front moves through
around 5am, PWATs rise from 0.5-0.75 inches to 1-1.5 inches, which
is 100-150% of normal. In terms of precipitation totals, the highest
rain totals will be confined to the mountains, which have a 50-60
percent chance and higher of seeing 0.10 inches or more. In the
Spokane, Pullman, and Lewiston areas, there is a 15-25 percent
chance of 0.10 inches or more through late Sunday evening. Areas
such as the Upper Columbia Basin and Moses Lake areas have the
lowest chances for precipitation totals of 0.10 inches with a
less than 10 percent chance. Most of this rain will fall early
this morning, before noon for most places. Temperatures will
drop considerably today, with highs being nearly 20 degrees
colder than what they were yesterday.
In the wake of the front, the atmosphere will destabilize as CAPE
values rise to 150-300 J/kg, low level lapse rates steepen, and
vorticity moves in behind the front. Current thunder probabilities
show a 10-20 percent chance of thunder in the Okanogan Highlands and
eastward, across the Spokane/Coeur d`Alene Areas, in the Central
Panhandle mountains, and across the Palouse. Highest probabilities
are in the northeast mountains, northern Okanogan Highlands, and
Northern Idaho Panhandle, with these areas seeing a 20-30 percent
chance of thunderstorms. As the cold front moves further away from
the area, thunderstorms will taper off quickly by the evening. Main
impacts with these thunderstorms include lightning, small hail, and
gusty outflow winds up to 40 mph.
Speaking of gusty winds, this afternoon will again have westerly
wind gusts 20-35 mph throughout much of the area due to onshore flow
combined with cold air advection from the front. Highest wind gusts
(30-35 mph) will be near Chelan County and the Waterville Plateau.
These gusty winds combined with the low rain totals anticipated
throughout the Waterville, Moses Lake, and Upper Columbia Basin
areas could result in some blowing dust issues along Highway 2 from
Waterville to Wilbur. Visibilities could drop down to a mile or less
in areas experiencing blowing dust. Smoke from current wildfires is
still impacting parts of the area, with an Air Quality Alert out for
Chelan County and the Wenatchee and Waterville Plateau areas until
further notice.
Monday through Wednesday: Once the low pressure system has moved out
of the area, higher heights will move in behind it, with a ridge
forming Monday night into Tuesday. Temperatures will begin
increasing each day and, much to the dismay of many, will be back in
the mid 80s by Wednesday. Winds will decrease by Monday, with breezy
afternoon winds near 10 mph moving through the region each day.
Thursday through next weekend: Ensemble analysis continues to favor
higher heights, indicating continued warmer than normal and dry
conditions through Friday. On Saturday, there are a couple signals
of a low pressure system approaching the PNW coast. However,
ensembles are split down the middle on this, with the other half
showing continued ridging through the area. /AS
&&
.AVIATION...
06Z TAFS: VFR conditions will continue for all TAF sites. Haze
and smoke will continue around wildfires and around Chelan,
Omak, and Colville, with some models indicating haze and smoke
may move into the Spokane/Coeur d`Alene area around 03Z
tomorrow. KLWS has some chances of rain ahead of the front,
though amounts will be very low. Most of the rain will come
after the front passes with chances near the Cascades through
southeast WA overnight and Sunday AM, expanding into northeast
WA and ID in the late morning to afternoon. Some isolated
afternoon thunderstorms are possible over NE WA and ID.
FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence
in VFR conditions for all TAF sites. High confidence in rain at
all TAF sites. Low to moderate confidence in afternoon
thunderstorms. Low confidence in smoke and haze bringing
visibilities down to MVFR.
-----------------------
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        67  43  70  46  79  49 /  50  30   0   0   0   0
Coeur d`Alene  68  44  70  46  79  50 /  60  40   0   0   0   0
Pullman        66  40  69  43  79  48 /  40  20   0   0   0   0
Lewiston       74  49  74  49  82  54 /  50  10   0   0   0   0
Colville       68  34  71  36  78  38 /  90  40   0   0   0   0
Sandpoint      67  40  67  41  76  45 /  70  70   0   0   0   0
Kellogg        67  45  68  49  79  54 /  60  50   0   0   0   0
Moses Lake     73  41  72  43  81  46 /  70   0   0   0   0   0
Wenatchee      72  49  73  52  79  56 /  70   0   0   0   0   0
Omak           74  44  74  48  80  51 /  70   0   0   0   0   0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
WA...Air Quality Alert until noon PDT Monday for Central Chelan
     County-Okanogan Valley-Waterville Plateau-Wenatchee Area-
     Western Chelan County.
ID...None.
&&
$$

NWS OTX Office Area Forecast Discussion