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880
FXUS66 KOTX 240502
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
1002 PM PDT Thu May 23 2024

.SYNOPSIS...
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Showers will continue across northeast Washington and north Idaho
through the early morning. Friday will feature warmer
temperatures with chances for afternoon and evening showers and
thunderstorms. Saturday will be cooler with breezy winds and light
precipitation. Dry weather returns on Sunday with temperatures
warming into the 70s to low 80s on Memorial Day. A return of cool,
wet weather is expected to return midweek.
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.DISCUSSION...
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Today through Saturday: There is a 20-40% chance of
showers/thunderstorms generally north of Highway 2 today. CAMs
have underdone convection a bit in the Waterville Plateau this
afternoon but otherwise they are tracking fairly well. Models
continue to show this activity nearing the Spokane metro around
the evening rush hour, but the  highest chances for some beefy
showers are north of the city. Storms have been capable of hail up
to half an inch (north of the Canadian border so far) and
isolated lightning. A weak shortwave will bring the same chances
for showers back tomorrow in much of the same areas plus the Blue
Mountains/ID Panhandle south of I-90.

Models diverge Saturday where the majority of the GEFS/GEPS
ensemble bring a 500 mb low into central/southern WA while the EPS
brings the 500 mb low in southern Canada bringing the chance for
gusty winds. If the GEFS/GEPS solution comes to fruition, I would
expect greater chances of showers for the Inland Northwest
particularly around Spokane. If the EPS is closer, it would
generally be drier. I am leaning towards the majority solution
(wetter and less windy Saturday). /Butler

Sunday and Memorial Day: There is good model agreement that our
holiday weekend will trend drier and warmer Sunday and Monday.
With the exception of a 20 percent chance of light showers in the
mountains north of Sandpoint and Metaline on Sunday, the remainder
of the Inland Northwest has a dry forecast Sunday and Monday.
Medium range ensemble consensus is for a flat high pressure ridge
Sunday to amplify Monday into Tuesday. After a chilly start to the
day Sunday, look for highs to rebound close to average with
afternoon temperatures ranging from the low to mid 60s in north
Idaho to the low 70s in central Washington and the L-C Valley.
Memorial Day will be a good day for outdoor activities. Partly to
mostly sunny skies are expected with winds in the 5 to 15 mph
range and high temperatures between 70 and 80.

Tuesday: The National Blend of Models (NBM) advertises the
arrival of a cold front Tuesday afternoon and evening. Ensemble
consensus is Tuesday will be as warm or warmer than Monday. Many
of the Canadian ensemble members suggest Tuesday could be
significantly warmer with widespread 80s and a handful of hot
spots like Moses Lake and Lewiston near 90. The timing of the cold
front will be worth watching. The NBM generates a 20 to 30
percent chance of thunderstorms across southeast Washington, the
Idaho Panhandle and northeast Washington Tuesday afternoon and
evening. The chance of measurable precipitation in central
Washington and across the Columbia Basin is 10 percent or less
according to the current NBM to as high as 30 percent along the
Canadian border of northeast WA and north ID. Needless to say,
Tuesday`s front has a significantly lower potential for producing
widespread rains than our system for Saturday.

Wednesday and Thursday: Temperatures are expected to be near
average Wed and Thu following the passage of Tuesday`s front.
Highs in the upper 60s to mid 70s are advertised by the NBM.
Precipitation chances are in question. There is a good deal of
ensemble spread by mid to late week. The ensemble blend produces
some 20 to 30 percent chances Thursday mainly over our mountainous
terrain. /GKoch
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&&

.AVIATION...
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06Z TAFS: Persistent showers across northeast Washington and north
Idaho will result in a very moist boundary layer tonight,
promoting the development of low clouds and fog in the sheltered
valleys, including Colville, Deer Park, Sandpoint, and Bonners
Ferry. Breezy south-southeast winds continuing across southeast
Washington into KGEG may hinder the low cloud development tonight,
with only a 5% chance for MVFR ceilings at KGEG overnight. A weak
system will approach the Inland Northwest early Friday afternoon
with showers developing across KPUW/KLWS Friday afternoon and
evening.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS:
There is moderate confidence (50% chance) for MVFR ceilings to
develop over the northern valleys overnight. There is very low
confidence in the development of MVFR ceilings tonight for KGEG-
KSFF given the lack of precipitation there this evening. There is
a 15% chance for MVFR ceilings at KCOE.

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

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
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&&

.PRELIMINARY POINT TEMPS/POPS...
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Spokane        45  68  46  61  41  65 /  10  10  30  30  10   0
Coeur d`Alene  44  66  46  57  41  61 /  20  20  40  50  10   0
Pullman        39  64  43  56  39  63 /   0  20  40  40  10   0
Lewiston       46  72  51  65  46  72 /   0  30  40  40  10   0
Colville       38  67  40  61  36  63 /  50  30  30  70  10  10
Sandpoint      43  63  44  55  41  58 /  60  30  40  70  20  10
Kellogg        45  63  46  53  42  59 /  10  30  40  70  20   0
Moses Lake     43  71  46  67  40  72 /   0  10  10  10   0   0
Wenatchee      47  68  48  64  45  71 /   0  10  10  10   0   0
Omak           43  71  46  68  41  70 /  10  20  20  30   0   0
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&&

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

$$