498
FXUS66 KOTX 101144
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
444 AM PDT Fri May 10 2024

.SYNOPSIS...
Temperatures today through the weekend warm to the highest values
of the season so far, with highs reaching the 80s and a few areas
the lower 90s. The weather pattern for early next week is
uncertain, however a cooling trend is likely with increasing
clouds, and a small chance of precipitation for the Cascade Crest,
northeast Washington, and the northern half of the Idaho Panhandle.


&&

.DISCUSSION...
Friday through Sunday: Dry and quiet weather will continue through
Saturday as a large ridge  sits over the Pacific Northwest and a
closed upper level low sits over Great Basin. This rex block pattern
will keep the ridge nearly stationary over the northwest today and
tomorrow. This will allow temperatures to warm into the upper 70s to
low 90s today and tomorrow, which are about 10 to 20 degrees above
average for this time of the year. Those who are sensitive to heat
or not yet acclimated to this type of heat should plan to take some
extra precautions if planning to spend time outside this weekend.
Water temperatures for lakes and rivers across the region are on
average in the upper 40s and low 50s. Please be mindful of this if
planning to spend some time near or on the water. Hypothermia and
loss of muscle control happens very quickly when swimming in water
temperatures this low.

The ridge will begin to weaken and shift eastward late Saturday into
Sunday as a shortwave approaches the northwest. The cross-Cascade
pressure gradient will begin to tighten Saturday afternoon and
evening as the flow shifts onshore, resulting in breezy winds
through the Cascade valleys. As the shortwave nears Sunday, the
Cascade valleys will experience some marginal cooling, but
temperatures will still be very warm regionwide. Winds will pick up
region wide on Sunday. Current forecast has the strongest gusts
across the lee of the Cascades from the Okanogan Valley, the
Waterville Plateau, and the western Columbia Basin. Following the
stretch of very warm and dry weather, these winds will bring an
increased risk for quick moving dead grass and brush fires. /vmt

Sunday night to Thursday: The ridge flattens near the start of
the week, with a shortwave trough migrating through before there
is an opportunity for the ridge to rebound toward the middle part
of next week. However by mid to late week guidance continues to
diverge, showing either an amplifying ridge or another wave coming
in. First between Sunday night and Tuesday look for variable
cloud cover, with breezy conditions. Limited shower chances will
be found near the Cascade crest and Canadian border Sunday night,
expanding over more of the northern WA and ID Panhandle mountains
for Monday and Tuesday. The best chances, overall, appear to be
Monday. Some guidance even expands some potential over
Spokane/CdA and Palouse. I give a nod to ensembles painting a
10-40% chance of measurable precipitation by adding some slight
chances around the Spokane/CdA area; I held off on the Palouse as
the ensembles probabilities are more borderline there. There will
also be limited t-storm chances especially on Monday afternoon
and evening, with the shortwave encountering a projected 200-400
J/kg of SBCAPE. However Sunday evening may also see a few embedded
t-storms. These chances will largely be toward the NE WA and N ID
Mountains.

As for winds, the incoming shortwave will bring some of the
stronger winds near the Cascades expanding out into the western
Columbia Basin Sunday night. Sustained winds between 15-25 mph
will be possible with gusts up to about 40 mph. Elsewhere winds
will increase some with gusts near 15-20 mph. Broader breezy
conditions will be found Monday and Tuesday, though the extremes
are more washed out by then as the primary front will have shifted
through leaving sustained winds 10-15 mph and gusts of 20-25 mph.

Heading into Wednesday and Thursday the model disagreement starts
to impact the forecast. If a stronger ridge returns it will be
drier and if a trough dominates it will be wetter. A middle ground
approach shows some slight to chance PoPs around the mountain
zones and eastern third of WA and lower ID. It will also remain
potentially breezy, but marginally.

Temperatures drop down Monday into Tuesday with the trough in the
region, meaning highs in the upper 60s and 70s, with a few areas
near 80 in the deeper Columbia Basin. Wednesday into Thursday
forecast temperatures are held near persistence from Monday and
Tuesday. However if the ridge manifests stronger it could be
warmer and if a deeper trough comes in it could be cooler. Models
show about a 20 degree range in potential highs by Thursday. For
example, most recent guidance in Spokane shows it could be as cool
as 65 or as warm as 81. /Solveig

&&

.AVIATION...
12Z TAFS: Widespread VFR conditions are expected through the TAF
period as high pressure builds over the region. Winds will be
light through the period except for breezy winds through the
Cascades valleys, including KEAT, in the evenings.


FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS:
There is very high confidence for VFR conditions across all TAF
sites.

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

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        80  49  82  53  83  53 /   0   0   0   0   0   0
Coeur d`Alene  79  49  80  52  80  51 /   0   0   0   0   0   0
Pullman        76  48  79  51  78  51 /   0   0   0   0   0   0
Lewiston       81  54  85  56  86  56 /   0   0   0   0   0   0
Colville       82  47  83  48  83  48 /   0   0   0   0   0  10
Sandpoint      77  49  79  51  78  50 /   0   0   0   0   0  10
Kellogg        76  52  77  54  77  53 /   0   0   0   0   0  10
Moses Lake     86  52  89  52  89  53 /   0   0   0   0   0   0
Wenatchee      84  58  88  58  86  55 /   0   0   0   0   0   0
Omak           86  53  89  53  88  52 /   0   0   0   0   0   0

&&

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

$$