912
FXUS66 KOTX 110500
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
1000 PM PDT Mon Jun 10 2024

.SYNOPSIS...
A dry cold front arrives Tuesday afternoon ushering gusty
westerly winds across the region. Breezy conditions continue into
Wednesday with cooler temperatures. Temperatures rebound on
Thursday then a pattern shift late in the week will lead to cooler
temperatures, another round of gusty winds, and shower chances
for Friday into the weekend.

&&

.DISCUSSION...

Tonight through Wednesday night:  A progressive, spring weather pattern
will continue across the Northwest through this period. During
the next 12 hours, shortwave ridging will be passing through. This
is delivering stable weather conditions, temperatures a handful
degrees of average, and light breezes of 15-20 mph. Quickly on its
heels, the next area of low pressure is swinging to the coast and
will begin crossing 130W by midnight. This wave will swing into
the Northwest on Tuesday delivering our next bout of gusty winds.
The system will largely be moisture deprived with just a 10-20%
chance for showers along the immediate Cascade Crest and immediate
Canadian Border. The more impactful element of the system will be
strong winds arriving with the cold front in the afternoon and
early evening. The Inland Northwest should brace for another round
of sustained winds of 15-30 mph with gusts of 30-45 mph. The
windiest locations will be found in the lee of the Cascades and
into the Western Columbia Basin. Wind advisories have been issued
to address these areas although, some of these stronger winds will
likely expand across the Upper Columbia Basin along Highway 2
into Wilbur and Davenport. The foothills of the Blue Mountains
will be another wind prone area. The sheltered northern valleys
will experience lower sustained speeds of 10 mph or less but
afternoon mixing will likely transport wind gusts up to 30 mph at
times into the valley floors. The winds will be driven by a 16 mb
cross-cwa pressure gradient and enhanced by cold air advection
late in the day into the evening.

Impacts: Use caution around dry grasses with the potential for new
fire starts to become problematic for local resources. Grasses on
south aspects and in the Western Columbia Basin are quickly
curing and will support fire spread. Those venturing on area lakes
in small vessels such as kayaks should be prepared for choppy,
changing conditions throughout the afternoon.

Winds will remain elevated Tuesday night but speeds will be
significantly lighter compared to the early evening. Much drier
air will continue to flood into the region. Locations that
decouple from the winds will cool sharply with overnight
temperatures dipping into the upper 30s to lower 40s; otherwise
the winds will keep temperatures in the 40s and 50s. Zonal or
westerly flow will remain over the region on Wednesday with
continued breezy conditions. Wind gusts in the afternoon will be
lower, only topping out near 25 mph. Temperatures on Wednesday
will be nearly 10 degrees cooler than Tuesday topping out in the
70s. /sb

Thursday to Monday: The Inland NW starts off this period dry and
mild, before the next system moves in with cooler temperatures,
breezy conditions and, for some, a chance of showers and
thunderstorms and even be some high terrain snow. Patchy frost is
also possible toward Saturday night/Sunday morning in some of the
sheltered northern valleys. First Thursday a shortwave ridge
migrates across the Pacific Northwest and pushes toward the
northern Continental Divide Thursday night, while a deep low
approach the Pacific Northwest coast. Highs are forecast to reach
the upper 70s to mid-80s. Skies will be mostly clear to partly
cloudy during the day, then clouds start to increase heading into
later Thursday into Thursday night.

Friday into Saturday a couple shortwave disturbances pivot around
the approaching low and cross the region, thickening clouds and
another increase in winds. Winds actually start increasing
overnight into Friday morning near the Cascades and increase
throughout the region heading through the day, peaking once in the
evening, subsiding some overnight and then increasing again
through Saturday afternoon. Speeds of 15-30 mph, with gusts of 30
to 40 mph will be possible, strongest around the lee of the
Cascades through the Waterville Plateau and Upper Columbia Basin.
In terms of fire weather concerns, afternoon RH values will hover
near critical values, especially Friday so this will be need to be
monitored. Wind gradually decline late Saturday night into Sunday
morning.

Precipitation-wise, the main precipitation chances lay near the
Cascade crest Friday and perhaps skimming near the Canadian
border. By Saturday the atmosphere moistens up some and the
threats of showers expands over most of the Cascades and northern
mountains and central Panhandle mountains, with a risk for snow in
the higher terrain. Some snow may be found near Washington Pass
and a rain/snow mix could even be seen near Stevens and Sherman
Pass. It is borderline for showers outside of those mountain
zones. Places like Spokane and Coeur d`Alene and the Palouse were
held to just a ten percent chance. Thunderstorms are possible
around the northern mountains Saturday afternoon. Some could be
locally stronger and could enhance the synoptic scale winds.

Sunday and Monday the area remains in a troughy pattern, but
models really start to diverge over the details of where the
individual features lay. The overall pattern will favor continued
shower chances around the mountain zones and at least a slight
chance around the eastern third of WA and lower ID. As the models
start to settle on a solution confidence in who will have the
higher risk will start to come into focus. A limited risk for
t-storms will linger over the northern mountains too. Wind will
still remain a bit breezy, but not as much as previous days with
gusts near 10-20 mph strongest near the Cascades to Waterville
Plateau.

As for temperatures they being to drop heading into Friday and
especially the weekend. Highs on Friday are forecast in the 70s
to near 80, then 60s to mid-70s for the weekend, then warming a
couple degrees on Monday. Lows are forecast to be in the 50s
Friday morning, the 40s to near 50 Saturday morning, then the 30s
to mid-40s Sunday morning, moderating slightly Monday morning.
These latter cooler temperatures could bring some frost to the
sheltered valleys near the Cascades and Canadian border counties.
Overnight Saturday into Sunday morning has the highest risk. As
we get closer we will have more confidence, but could impact
anyone with sensitive plants or crops. /Solveig


&&

.AVIATION...
06Z TAFS: High level clouds are beginning to move in from the
west ahead of an approaching cold front. The cold front will
quickly move through the region on Tuesday with winds increasing
around 18z then becoming strong from 21-03Z. Sustained winds 20-30
mph with gusts around 40 mph expected for most sites across the
Basin and within the aligned Cascade valleys. This includes
Wenatchee, Chelan, Ritzville, Pullman, and Spokane. The sheltered
northern valleys will experience sustained winds closer to 10 to
15 mph with infrequent gusts 20-30 mph. Conditions are expected to
remain VFR over the next 24 hours with no precipitation from the
cold front.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS:
Confidence is high for VFR skies through the period and for windy
conditions Tuesday afternoon and early evening. Confidence is high
for wind gusts to 30 mph and moderate for wind gusts in excess of
40 mph. Highest probabilities for gusts in excess of 40 mph is
around Wenatchee, Moses Lake, Douglas, and Ephrata.

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

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        55  83  46  74  45  79 /   0   0   0   0   0   0
Coeur d`Alene  53  79  45  71  44  79 /   0   0   0   0   0   0
Pullman        51  78  45  69  44  77 /   0   0   0   0   0   0
Lewiston       58  89  54  79  50  87 /   0   0   0   0   0   0
Colville       48  80  40  74  40  79 /   0  10   0   0   0   0
Sandpoint      51  78  44  70  42  77 /   0  10   0   0   0   0
Kellogg        55  76  48  67  47  77 /   0   0   0   0   0   0
Moses Lake     55  87  47  79  46  83 /   0   0   0   0   0   0
Wenatchee      60  80  50  76  49  82 /   0   0   0   0   0   0
Omak           55  84  46  79  47  83 /   0   0   0   0   0   0

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Wind Advisory from noon to 8 PM PDT Tuesday for Moses Lake Area-
     Waterville Plateau-Wenatchee Area.

&&

$$