National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS66 KOTX 252226
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
326 PM PDT Thu Apr 25 2024

.SYNOPSIS...
Rain will spread into eastern Washington and north Idaho this
evening and linger into Friday morning. The weekend and early
next week will feature showery weather over the mountains and
seasonably cool temperatures. Sunday and Monday have the potential
to be windy with the passage of a vigorous frontal system.

&&

.DISCUSSION...

Tonight into Friday: As of 2 PM, bands of rain were spreading into
central Washington. The Wenatchee, Yakima, and Ellensburg airports
had received a couple hundredths of an inch of rain, and light
rain had spread into Ephrata and Moses Lake. By early evening,
light rain bands will be approaching the Washington/Idaho state
line. Despite the abundance of deep layer moisture with
subtropical Pacific origins, rain amounts don`t look impressive.
As the front moves across eastern Washington into north Idaho, it
will splitting as the upper trough axis digs into southern Oregon
and northern California. Frontal rain bands will also be fighting
the central Washington downslope "rain shadow". Ensemble based
guidance from the National Blend of Models only generates a few
hundredths of an inch of rain this afternoon and evening across
the Moses Lake area and the Columbia Basin. Spokane, Coeur
d`Alene, and Pullman only have a 10 percent chance of a tenth of
an inch by Friday morning. The only spots that have a greater than
50 percent of exceeding a quarter inch of rain tonight through
Friday afternoon are mountainous areas north of Republic,
Colville, Ione, and Sandpoint as well as the crest of the
Cascades. Scattered post frontal showers will produce hit or miss
rain Friday afternoon and evening. These showers will be the most
concentrated over the mountains of north central and northeast
Washington as mid-level southerly flow will contribute to
orographic enhancement over the high terrain of Okanogan, Ferry,
Stevens and Pend Oreille counties. There is a 10 to 20 percent
chance of lightning Friday afternoon for these orographically
favored areas as well.

Saturday: A weak upper trough will linger over the Inland
Northwest on Saturday promoting another round of scattered mainly
terrain enhanced showers. Again, a handful of lightning strikes
are possible in our counties along the Canadian border with a 10
to 20 percent chance of spring thunderstorms for Ferry, Stevens,
Pend Oreille, and Boundary counties. With the exception of these
scattered showers, Saturday looks favorable for outdoor activities
with afternoon highs ranging from the upper 50s in the Idaho
Panhandle to the mid 60s in the Columbia Basin and Lewiston
area. South winds will generally be in the 10 to 15 mph range with
localized gusts to 25 mph over the Waterville Plateau and Okanogan
Valley.

Sunday and Monday: Our breeziest weather over the next 5 to 7 days
will occur Sunday and Monday as the Polar Jet becomes focused over
the Pacific Northwest. The various ensemble clusters advertise a
transition to a longwave trough over the Gulf of Alaska and
British Columbia Sunday and Monday, but there are differences in
the timing and strength of the shortwaves embedded within the
increasingly swift westerly flow over Washington and Idaho. At
this time, the most likely scenario supports increasingly breezy
south or southwest winds on Sunday as the upper trough leans into
the region followed by a distinctly cooler upper shortwave Sunday
night into Monday with stronger west winds. Unfortunately,
significant precipitation looks unlikely both Sunday and Monday
across the Columbia Basin, West Plains, and most of the Palouse.
There is a less than 5 percent chance of a tenth of an inch of
rain for Moses Lake and the Columbia Basin Sunday and Monday. And
less than a 10 percent chance of a tenth for the Palouse and West
Plains. With a good deal of spring farming activity during the
last 2 weeks and very little recent moisture, we are concerned
about blowing dust. The National Blend of Models generates a 30 to
40 percent probability of sustained winds of 20 mph or more across
these agricultural areas Sunday afternoon and again Monday. We
will continue to watch the wind forecast closely.

Tuesday through Thursday: The characteristics of the upper trough
over BC become inconsistent by Tuesday and Wednesday. The
majority of the ensembles sustain a trough along the coast...a
pattern favorable for scattered showers over the mountainous
terrain. However, about a quarter of the ensembles develop high
pressure over the Inland Northwest. Needless to say, temperature
distributions increase significantly in the National Blend of
Models output by the middle of next week with high temperatures
ranging from the 50s in the cool ensembles to the 70s in the
warmer ones. /GKoch

&&

.AVIATION...
00Z TAFS: A front passing through the region is beginning to
spread rain into eastern WA and north ID. Light rain has already
begun at MWH, EPH, and OMK, and is expected to reach the
remaining airports within the next couple of hours. Ceilings are
lowering, and potential for MVFR conditions will last into the
evening and overnight hours.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: Moderate
confidence in MVFR cigs around 01-06z light rain band.
-----------------------

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        44  59  41  60  40  59 /  80  40  10  20  10  20
Coeur d`Alene  44  56  41  58  41  56 /  90  60  20  40  10  30
Pullman        43  57  40  57  40  57 /  80  40  20  20  10  20
Lewiston       48  64  45  64  46  65 /  80  50  10  10  10  10
Colville       41  58  38  60  36  58 /  90  80  40  60  30  30
Sandpoint      44  55  41  57  41  53 /  90  70  40  70  40  70
Kellogg        44  54  44  55  43  52 /  90  80  40  70  30  60
Moses Lake     42  66  41  66  41  65 /  40  20  10   0   0   0
Wenatchee      46  62  45  62  42  62 /  40  30  10   0   0   0
Omak           46  64  44  65  39  64 /  80  60  20  20  10  10

&&

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

$$