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000
FXUS66 KOTX 241820
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
1120 AM PDT Wed Apr 24 2024

.SYNOPSIS...
Mild and mostly dry weather will continue across the Inland
Northwest today with afternoon temperatures in the 60s and 70s.
Breezy west winds will increase late in the day with the arrival
of a cold front. Cooler and showery weather is expected Thursday
through Monday.

&&

.DISCUSSION...

Today will be mild but more cloudy with increasing chances for
showers in the Cascades as an upper low in southern BC brings west
flow aloft. A weak frontal passage this afternoon will pose a very
slim risk of blowing dust on the Waterville Plateau but confidence
is very low. There is a 50% chance of gusts 30 mph or greater in the
afternoon hours which may create locally dusty conditions.

Another wave off the WA coast brings an increasingly moist airmass
to the INW Thursday. It will start off mostly dry in the morning
thanks to shadowing but precip chances increase in the afternoon
hours as the flow becomes increasingly south aloft. The wave slows
down inland keeping precip chances into Friday with a conditionally
unstable airmass. There still remains a slim chance (15%) of thunder
in the northern mountains and the ID Panhandle. It is expected to
bring a round of much needed showers to the Inland Northwest with
most areas with at least a 30% probability of at least a tenth of an
inch of precip. Higher terrains of the Cascades and northern
mountains could receive near a quarter of an inch. The east slopes
of the Cascades is expected to be impacted by the rain shadow effect
and should receive less. The airmass is much cooler as well with
highs staying in the 50s and low 60s both Thursday and Friday.

Multiple impulses off a parent trough in the Gulf of Alaska
bringing chances for mountain snow and valley rain. Flow orientation
is split between north/west/south with each impulse which would
greatly influence the amount of shadowing. /DB

&&

.AVIATION...
18Z TAFS: A dry cold front will move across eastern Washington and
north Idaho bringing several hours of gusty winds this afternoon
and evening to the majority of airports in the region. Gusts in
the 20-25kt range will be possible through the Cascade gaps
including Wenatchee, Chelan, and Ephrata. Guidance from the HREF, GFS
MOS, and model soundings from the GFS and NAM generate clouds in
the 2000-3500ft range Thursday as early as 14z across north Idaho
and the eastern third of Washington. Rises in low level humidity
combined with warming after sunrise will likely produce a
scattered to broken stratocumulus deck around Spokane, Coeur
d`Alene, Pullman, and other north Idaho/northeast Washington
airports. /GKoch

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: HREF probabilities
of ceilings below 3000ft peak around 30 to 50 percent for Spokane,
Coeur d`Alene, and Pullman between 16 and 20z and was the
preferred guidance for the TAFs. GFS MOS advertises 2500ft
ceilings around Spokane and Coeur d`Alene as early as 14z which
looks early compared to model soundings from the NAM and GFS.
/GKoch

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

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  41  59  43  55  41 /   0   0  10  70  70  20
Coeur d`Alene  63  40  57  43  52  41 /   0   0  20  70  80  30
Pullman        61  39  57  43  53  41 /   0   0  10  80  80  40
Lewiston       70  45  65  48  60  46 /   0   0  10  70  70  30
Colville       65  37  61  41  56  39 /   0   0  20  80  90  50
Sandpoint      63  41  55  43  51  41 /   0   0  30  70  90  50
Kellogg        62  42  54  45  51  43 /   0   0  40  70  90  50
Moses Lake     69  42  63  44  63  42 /   0   0  10  30  30  10
Wenatchee      65  44  60  46  61  44 /   0   0  20  20  20  10
Omak           68  41  63  45  61  43 /   0   0  10  60  50  30

&&

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

$$