450
FXUS66 KOTX 162346
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
446 PM PDT Thu May 16 2024

.SYNOPSIS...
The arrival of a vigorous cold front this afternoon and evening will
produce widespread windy conditions, with gusts as high as 40 to
50 mph across parts of central and eastern Washington and down to
the Lewiston and Camas Prairie region. Gusty west winds will
continue into Friday, with significantly cooler temperatures.
Seasonably cool and showery weather is expected this weekend into
next week.

&&

.DISCUSSION...
Tonight through Saturday Night: A robust cold front with an
associated strong upper level jet will move into the region this
evening. There is a 20% chance of showers this evening along the
US/Canadian border and a 50-60% chance along the crest of the
Cascades. The more significant impact will be the windy conditions
that are already being seen across the region. Gusts to 40 mph
have already been reported around Douglas, Entiat, Moses Lake,
Spokane, and Athol. Dodson Road just west of Moses Lake, Moses
Lake and the Omak area are reporting reduced visibilities with
some blowing dust. Winds will peak with the front this evening.
Locally, gusts could reach 50 mph.

*Impacts would include blowing dust across portions of the
 Columbia Basin and Okanogan Valley, especially near any recently
 plowed or worked fields; small branches broken; isolated power
 outages; rough waters on area lakes and the Columbia River; and
 unsecured objects being blown around.

Winds will continue through the night, tho not be as strong as
with the front, but enough to warrant the wind advisories
continuing. There is a 30-40% chance of showers developing across
portions of the Idaho Panhandle and extreme eastern WA overnight
and early Friday morning.

Winds will continue through Friday morning before decreasing in
the afternoon. The upper level trough moves into the area with
cold 500 mb temps. Have a 20% of afternoon thunderstorms for
northeast Washington the the ID Panhandle with a 30-50% chance of
showers.

Saturday another wave moves into the region which will provide
more showers, especially across northern WA and ID.

Temperatures will be below average with highs in the 60s. Low
temps tonight will be in the mid 30s to near 50, because of the
winds keeping things well mixed. Low temps go down for Sat and
Sunday morning into the mid 30s to low 40s, with some of the
typical cold spots potentially reaching near freezing (Republic,
Colville, Deer Park, Priest Lake) with frost possible. /Nisbet

Sunday:  Model consensus remains high that a strong
upper level low will be parked over extreme eastern WA and N ID
during the morning hours before trudging slowly into SW MT by the
afternoon. This will equate to wet and rather cool weather with
numerous showers expected in and around the low. There will also
be a chance of afternoon thunderstorms as 500 mb temperatures will
be -25c or colder which will result in small CAPEs over NE WA
into N ID. Precipitation amounts wont be terribly heavy due to a
relatively dry precipitable water content, however slow moving
showers/storms could produce moderate amounts over isolated
locations. Overall we expect precipitation amounts to range from a
few hundredths of an inch to around a tenth of an inch. Over
central Washington we expect little if any precipitation. High
temperatures will be cool with readings in the mid 50s to mid 60s.

Monday will likely be the driest/warmest day of the next 7 as
there is good model agreement that we will see a brief shortwave
ridge build over the region. The GEFS solutions are a little less
sure of the ridging and hold onto some residual instability
primarily over extreme E WA and the ID Panhandle. As such we will
hold onto a small chance of showers and afternoon thunderstorms,
but this only represents about a quarter of the ensemble
solutions. High temperatures will bounce back from the cool Sunday
readings with highs in the 60s to lower 70s.

Tuesday through Thursday: Ensemble agreement is very good that
the next strong upper level low will move into the region
sometime Tuesday and remain entrenched over the area through
Thursday. This will equate to a renewed chance of showers each day
with a small chance of thunderstorms. Once again, the
precipitable water values will remain low and thus the total
precipitation amounts will be relatively light. For the three day
period precipitation amounts will likely range from 0.15-0.30 for
most of eastern WA, 0.20-0.50 for the ID Panhandle, and less
than 0.10 for central WA. Meanwhile high temperatures will
generally be in the upper 50s and 60s. fx

&&

.AVIATION...
00Z TAFS: Band of blowing dust is making its way across the
Columbia Basin toward the West Plains as seen on satellite and web
cams with brief MVFR conditions along with wind gusts of 35-40
kts. Scattered showers will continue across the northeast WA and
north ID mountains through the evening. Gusty winds will prevail
through the evening and even overnight with the passage of the
upper level front with gusts of 25-35kt. Ceilings will lower from
KCOE to KPUW with light showers possible early in the morning
while a chance of showers continues for the afternoon for much of
north ID. Dry VFR conditions will be found across much of central
WA through the period. /rfox.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: Visibility
reduction to 3-5SM with blowing dust has a low to mod probability
of occurrence, but is possible near KGEG based on current
observations. Dust is just as much a function of recent field work
as it is wind speed. Low chances for MVFR conditions with clouds
showers over southeast WA and north ID early Friday morning.
/rfox.

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

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        43  63  39  63  40  60 /  10  20   0  10  20  30
Coeur d`Alene  44  59  38  60  39  56 /  40  40  10  10  30  40
Pullman        43  58  37  61  38  57 /  40  20   0   0  20  20
Lewiston       51  67  43  69  44  64 /  20  10   0   0  10  20
Colville       36  64  33  62  35  60 /  20  30  10  50  50  60
Sandpoint      43  57  37  58  38  55 /  30  60  20  40  50  70
Kellogg        43  54  40  58  41  52 /  60  60  10  20  30  60
Moses Lake     43  69  40  69  40  69 /  10   0   0   0   0  10
Wenatchee      46  64  44  64  43  66 /  10   0   0   0   0   0
Omak           42  69  39  66  40  68 /   0  10   0  20  20  10

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Wind Advisory until noon PDT Friday for Idaho Palouse-Lewis and
     Southern Nez Perce Counties-Lewiston Area.

WA...Wind Advisory until noon PDT Friday for Lower Garfield and
     Asotin Counties-Spokane Area-Washington Palouse.

     Wind Advisory until noon PDT Friday for Moses Lake Area-Upper
     Columbia Basin-Waterville Plateau-Wenatchee Area.

&&

$$