259
FXUS66 KOTX 241834
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
1134 AM PDT Sat May 24 2025

.KEY MESSAGES...

- Warmer through Sunday with widespread Minor HeatRisk.
  Temperatures warming into the 80s and low 90s by Sunday.
  Water temperatures remain cold.

- Scattered showers with a 10-20 percent chance of
  thunderstorms Sunday night into Memorial Day.

- Breezy winds in the 30 mph range across the Basin and Cascade
  Valleys for Monday.

&&

.SYNOPSIS...
Temperatures will gradually warm through Sunday as high
temperatures warm into the upper 70s and low 90s for the
weekend. There is growing potential for showers and
thunderstorms from Sunday night into Memorial Day. Warmer and
drier weather is then expected to return for much of next week.

&&

.DISCUSSION...

Saturday and Sunday: A warm holiday weekend is on tap as models are
in good agreement for an upper level ridge to strengthen over the
Inland Northwest through the day today as a slow moving cold front
and upper level trough near the west coast. The ridge will continue
to amplify over the Inland Northwest and the Northern Rockies on
Sunday with increasing southerly flow.  There is high confidence for
temperatures to warm into the mid 70s to low 80s on Saturday, then
further warm on Sunday with widespread highs in the 80s. Places
below 1000 feet in elevation in the Cascade valleys, the
Columbia Basin, and the L-C valley have an 80 percent chance or
greater for high temperatures above 90F. These temperatures will
be 13 to 18 degrees above average for this time of year. Most
of the region will experience a minor risk for heat related
illnesses both days with a moderate risk for elevations below
1000 feet on Sunday. Although these temperatures will feel quite
warm, they will not be contenders for record values as high
temperatures would need to be about 10 degrees warmer to enter
record territory. Nonetheless, those planning to spend the
holiday weekend out on the lake or river should prepare for very
cold water temperatures. Please wear a life jacket if heading
out on the water.

Sunday night into Monday: There is high confidence for the weak
front and upper level through to move onshore Sunday night into
Monday. Deep southerly flow ahead of the cold front will bring
anomalous moisture into the Inland Northwest with PWATs 150-200
percent of normal. Medium range CAMs show showers moving into
central Washington late Sunday night and then gradually shifting to
the north-northeast by early Monday morning. There may be enough
residual elevated instability (100 to 300 J/kg of MUCAPE) late
Sunday night for isolated to scattered thunderstorms across central
Washington (10 to 20 percent chance). High temperatures on Monday
are currently forecasted to cool by about 10 degrees compared to
Sunday. In addition to the thunderstorm potential, breezy west to
southwest winds will accompany the cool down. Sustained winds of 15
to 25 mph with wind gusts 25 to 35 mph will be common in the
afternoon.

Tuesday through Friday: Models are in general agreement for the
upper level ridge to rebuild over the Inland Northwest with
temperatures trending into the 80s and low 90s by Wednesday.
Confidence in the forecast wanes for Thursday as about 40 percent of
the global ensembles show an upper level trough temporarily
flattening the ridge with 60 percent holding on to an amplified
ridge. The flattening ridge scenario would support showers and
thunderstorms and breezy winds on Thursday with slightly cooler
temperatures into Friday. The other scenario with the ridge
remaining amplified would keep the forecast warm and dry for
Thursday and Friday. Looking into the most recent deterministic
guidance reveals that the ECMWF and GFS both show some
flattening to the ridge, with the GFS a bit more robust than the
ECMWF. Interestingly, the ECMWF AI weather model aligns more
closely to the GFS with a more robust trough passage. This will
continue to be monitored through the next couple of days. /vmt

&&

.AVIATION...
18Z TAFS: High pressure aloft will deliver VFR skies and light
winds through 18z Sunday. Heads up, there will be an increasing
risk for showers and embedded thunderstorms across Central WA
after Sunday evening (after 02z) with the threat shifting slowly
eastward early Monday morning.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence
in VFR conditions. Moderate confidence for convection to move
into Central WA Sunday evening and night with the passage of a
cold front.

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

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        75  49  83  54  71  46 /   0   0   0  20  30  10
Coeur d`Alene  75  48  84  53  70  47 /   0   0   0  20  30  10
Pullman        73  48  82  51  67  45 /   0   0   0  20  30  10
Lewiston       80  53  89  58  75  52 /   0   0   0  20  20  10
Colville       76  44  84  50  72  43 /   0   0   0  30  60  20
Sandpoint      74  48  86  52  71  47 /   0   0   0  10  40  10
Kellogg        73  52  83  54  68  48 /   0   0   0  10  30  10
Moses Lake     81  50  89  57  77  47 /   0   0   0  50  20   0
Wenatchee      80  56  87  58  75  50 /   0   0   0  50  20   0
Omak           80  50  87  55  76  47 /   0   0   0  60  40  10

&&

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

&&

$$