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000
FXUS66 KOTX 201812
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
1112 AM PDT Sat Apr 20 2024

.SYNOPSIS...
Dry weather conditions will be in place through Saturday. A
strong cold front arrives this evening and overnight ushering
gusty westerly winds and chance for showers. Mild and dry weather
returns for the start of work week with 60s and 70s by Tuesday.
The next cooling trend arrives Wednesday with small chances for
mountain showers.

&&

.DISCUSSION...
Today: It will be a gorgeous start to the weekend courtesy of high
pressure aloft and an abnormally dry air mass. Skies are clear
this morning and will remain cloud free through the afternoon
delivering an abundance of sunshine! Temperatures are also
starting off warmer than Friday morning as a light northeast wind
continues to blow across the region. The combination of steady
winds and the very dry air mass will allow temperatures to warm
quickly today with readings into the 60s shortly after noon. Winds
will not be as breezy as Friday but steady within the 6 to 12 mph
range with direction shifting from northeast in the morning to
southeast throughout the day.

This evening - overnight: A strong cold front arrives bringing strong
winds and chance for showers. Latest models have sped up the
timing of the front now coming across the Cascades in the evening
and to the WA/ID border just prior to midnight. This is roughly
2-3 hours sooner than runs were showing last night. There is high
confidence for a drastic increase in winds with the frontal
passage with speeds sustained winds at least 20 mph. This comes
with probabilities of 50-80% or greater. Areas of the Upper
Columbia Basin along the Hwy 2 corridor from Douglas to Wilbur to
Airway Heights as well as southeastern WA including the Palouse,
Foothills of the Blue Mountains, and benches around the L-C Valley
will likely experience a few hours of sustained winds of 25 mph
or greater (30% chance). Wind gusts of 30-40 mph will be common
with and behind the frontal passage with a few gusts of 45 mph
possible over the aforementioned windier spots. This also includes
the ridge lines and aligned valleys in the East Slopes of the
Cascades and into the Idaho Panhandle. Typically, these strongest
speeds only last 1-2 hours along and behind the front. With the
last 48 hours being very dry ...still thinking patchy blowing dust
is a possibility in the Western Basin for early Sunday. Would not
rule out minor tree damage (small branches) and a few power
outages. The biggest impact will be light weight objects blowing
around like garbage cans, lawn furniture, and trampolines.
Saturday will tempting to sit out on the patio and BBQ...Please
don`t forget to secure those patio umbrellas and other loose items
before heading to bed!

As for rain showers, amounts have been lowered and range between a
trace to a tenth away from the Cascade Crest. Best chance for a
tenth will be the higher terrain of North Idaho and Northeastern
WA (70% chance) while the valleys carry less than a 20% chance for
a tenth. The Cascade Crest could receive upwards of a quarter of
an inch or more with amounts localized under narrow heavier bands.
Snow levels will come crashing down as well falling to 3000 feet
by midnight with slushy accumulations possible over
Stevens/Washington Passes.

Sunday: Breezy westerly winds will persist on Sunday with constant
wind speeds of 10-20 mph and gusts up to 30 mph. Winds will be
strongest early in the day and slowly come down as the day wears
on. Cold air aloft tracking along the International Border will
result in some cumulus buildups and a few shallow showers but
little in the way of additional rainfall. NBM carries a 10% chance
for a t-storm but this comes with very low confidence as
700-500mb is rapidly drying out and PWATS are crashing back near
0.25" across the Inland NW.

Monday through Friday: High pressure returns to the region early in
the work-week bringing another period of warming and drying.
Temperatures for Monday morning will likely start off cool with
temperatures in the upper 20s to lower 30s and potential for frost
or at least freezing temperatures. Temperatures rebound into the
60s by the afternoon and continue to warm into Tuesday numerous
locations across the Inland Northwest showing increasing odds for
reaching 70F (50-80% chances). This will come with generally
lighter winds. The next Pacific trough arrives middle to late
week. A closer examination of the 100 member ensemble shows quite
a bit of uncertainty with the track and strength of this wave. At
this time, only 30% of the members show the INW receiving
precipitation from this feature on Wednesday (mainly comprised of
the GEFS members)which only increases toward 37% by Thursday and
heavily weighted by the GEFS members. The precipitation is showery
in nature and mainly focused over the mountains. Confidence is
higher for some degree of cooling with the general pattern shift
and potential for an increase in westerly winds. In a nutshell,
temperatures peak Tuesday and cool into Thursday with readings not
straying very far from the 30-averages. /sb

&&

.AVIATION...
18z TAFS: Breezy northeast winds for the rest of this morning
particularly across north Idaho into northeast Washington and over
the Columbia Basin. Expect gusts up to 18-25 kts for KSZT-KCOE-
KDEW-KSFF-KGEG-KMWH airports until winds subside by mid
afternoon. A vigorous cold front will sweep across the region
tonight arriving into the Cascades by 0500Z and into the Idaho
Panhandle by 1100Z. Showers that develop will quickly push across
with the front with ceilings lowering to between 4-6 kft agl.
Expect a sharp wind shift from the west and northwest with gusts
to between 25-35 kts with cold front passage. Stronger wind gusts
of 30+ kts will be brief on the order of a few hours. The
stronger wind gusts may bring a brief period of blowing dust at
KMWH. A brief period of low level wind shear will also be
possible right ahead of the front tonight between 05-09Z as well.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: Confidence is high
that VFR conditions will prevail. There is low confidence for
blowing dust to reduce visibility at KMWH between 06-09Z tonight.
There is also a 30% chance for low stratus or stratocumulus
clouds to result in MVFR conditions at KPUW-KGEG-KCOE Sunday
morning. /SVH

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

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        64  39  56  32  60  36 /   0  40   0   0   0   0
Coeur d`Alene  62  39  54  31  59  34 /   0  60  10   0   0   0
Pullman        64  39  53  33  57  36 /   0  40   0   0   0   0
Lewiston       72  46  61  38  65  40 /   0  20   0   0   0   0
Colville       63  35  57  29  62  33 /   0  60  10   0   0   0
Sandpoint      59  39  52  32  57  35 /   0  70  30   0   0   0
Kellogg        62  40  50  34  56  37 /   0  60  20   0   0   0
Moses Lake     69  40  62  34  64  40 /   0  10   0   0   0   0
Wenatchee      64  41  58  37  63  43 /   0  10   0   0   0   0
Omak           65  39  61  34  64  39 /   0  20   0   0   0   0

&&

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

$$