936
FXUS66 KOTX 221154
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
454 AM PDT Wed May 22 2024

.SYNOPSIS...
A wet low pressure system will bring steady rain across the region
through Wednesday. Snow levels will drop down to pass level
with wet snow accumulations for travel over the Cascade crest.
Another weather system will move in on Friday and Saturday
bringing more unsettled weather into the Memorial Day weekend.
Monday will be the warmest day of the holiday weekend.

&&

.DISCUSSION...
Today: Satellite shows the low moving through southern Vancouver
Island early this morning. It will track to the southeast into
south central WA later this morning. As it does, precipitation
will wrap around the low and will keep rain and high mountain snow
occurring across much of the region. Temperatures and cameras
still show precip type as rain over the passes, but temperatures
will lower further, and rain/snow mix or slushy snow could
accumulate at the passes. Probability of an inch today for the
passes are: Washington Pass 60%; Stevens Pass 20%; Sherman Pass
30%. There is a 20% chance of afternoon thunderstorms across
northern WA/ID and across the Blue Mtns and Camas Prairie. Today
will be the coolest day of the week with temps in the 50s, which
is 10-15 degrees below average.

Precip chances continue through the evening, especially for
northern WA and the ID Panhandle. As the low slips into
southeastern Idaho overnight, our chances of precipitation
decreases except for the central and southern ID Panhandle. Slushy
wet snow accumulation is possible over Lookout Pass.

Thursday: We are between systems under northerly flow aloft as the
next trough begins to move toward the BC coast. Some partially
clearing skies Thursday morning and abundant low level moisture
from the rain will aid in afternoon instability and a 20-30%
chance of thunderstorms across northern WA and ID. Temperatures
rebound 5-10 degrees into the 60s top low 70s, which is still a
couple degrees below average.

The 20-30% chance of thunderstorms continues through the evening
hours, with showers confined to the north ID Panhandle overnight.

Rivers will continue to fill from the rains, but none are expected
to flood as we have been so dry, and these rains are proving very
beneficial to our region. /Nisbet

Friday through Wednesday: An upper level trough will continue
through the weekend. It will keep the cool, wet pattern through the
weekend. A Low will push through the region late Friday through
early Sunday. It will not have as moisture as the previous system
but still expected to bring amounts of 0.1-0.25". The band of
highest precip will be along North Washington and the the Idaho
Panhandle. With snow levels hovering around 4500ft in the Cascades,
light snow could bring minor impacts to travel over the Passes.
Little to no snow accumulation is expected. The Lower Central Basin
is expected to be the driest with little to no precip. By Sunday,
the shower potential decreases as a shallow ridge begins to cut off
the moisture plume. Highs will be in the 60s and low 70s. Overnight
lows will be in the upper 30s and 40s.

By Memorial Day, a trend warming trend will begin. Any shower
activity will be confined to the mountains. It will continue through
Tuesday. Highs will reach into the 70s and low 80s. Overnight lows
will be in the upper 40s and 50s. It will be short lived as ensembles
are showing a strong Gulf of Alaska low bringing another fetch of
moisture into the region late Tuesday and Wednesday. The Inland
Northwest will see another round of widespread showers. /JDC

&&

.AVIATION...
12Z TAFS: A weather system will bring MVFR/IFR conditions with
rain over the east third of WA and ID, including
GEG/SFF/COE/PUW/LWS. Some patchy fog/mist is possible thru the
early morning too. The precipitation wanes briefly around TAF
sites in the morning, but increase in the afternoon through
evening at all TAF sites as the low tracks just south of the area,
before starting to pull away later Wednesday evening. There will
be a small risk for t-storms in the afternoon across northern
WA/ID not impacting TAF locations, but around Republic, CQV,
Bonners Ferry, and down across the Blue Mtns and Camas Prairie of
ID. After sunset cigs for GEG/SFF/COE/PUW will lower down to MVFR
conditions.


FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS:
Moderate to high confidence in ceiling improving throughout the
day and then lowering again overnight.

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

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        57  40  64  45  67  45 /  80  20  30  10  10  40
Coeur d`Alene  53  40  60  45  65  45 /  90  30  40  20  20  50
Pullman        52  38  59  40  64  43 /  80  10  10   0  10  40
Lewiston       60  45  66  46  73  50 /  70  20  10   0  10  40
Colville       54  35  64  39  65  40 /  90  30  70  60  50  50
Sandpoint      50  38  58  44  62  44 / 100  60  60  50  50  60
Kellogg        50  42  57  45  62  46 / 100  60  40  20  40  60
Moses Lake     61  43  72  44  73  44 /  30  10   0   0  10  10
Wenatchee      59  47  71  47  70  47 /  20  10   0   0  10  10
Omak           60  43  72  45  70  45 /  70  20  30  10  20  30

&&

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

$$