778
FXUS66 KOTX 172345
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
445 PM PDT Tue Sep 17 2024

.SYNOPSIS...

Some light rain will persist at times over north Idaho and the
eastern third of Washington through early Wednesday. Conditions
will trend drier toward the end of the work week, then
precipitation chances return for the weekend.

&&

.DISCUSSION...

Tonight through Thursday: Upper level longwave trof lingers over a
good portion of the Western US through this interval. At least two
synoptic scale low pressure systems are nested inside it and
rotating around the upper level longwave`s edges. The showery
bands of precipitation extending outward from one such low
centered to our southeast over Southern Idaho/Northeast Nevada is
allowing for considerable cloud cover and narrow bands of
precipitation over far Eastern Washington and North Idaho to
linger on into tonight. As this low, and its associated showers
and cloud cover, treks to the northeast the clouds and showers
will be relegated to smaller portions of North Idaho Wednesday and
then eventually a drier forecast with clearing skies Wednesday
night and Thursday.

Friday through Tuesday: The upper level flow pattern is still
rather progressive as a more zonal north/northwest flow drapped
atop the large longwave trof Friday allows for drier air from the
northwest void of significant shortwaves to linger into the
weekend, although sometime late Saturday there is greater
likelihood of at least one frontal feature or more, with increased
moisture streaming into them, dropping through from the
northwest. With this in mind a increase in cloud cover along with
some minor pops and light QPF return to mark late Saturday and
beyond coupled with forecast temperatures generally quite near or
slightly below normal. Some patchy morning frost and fog appear in
very small isolated well sheltered locations of Northeast
Washington and the Idaho Panhandle. /Pelatti

&&

.AVIATION...
00Z TAFS: Scattered showers will rotate north up into SE Washington,
and the Idaho Panhandle tonight. Showers that form over TAF sites
may result in brief visibility reductions to MVFR. With a moist
boundary layer and middle to high level clouds thinning overnight,
a handful of model soundings are showing a marginal VFR
developing around KGEG, KSFF, KCOE, KDEW around 12Z Wednesday
morning.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: Moderate
confidence of increasing showers for southeast Washington and
north Idaho tonight. There is low confidence for stratus
development around KGEG, KSFF, KCOE, KDEW early Wednesday
morning.

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        73  49  76  49  76  47 /  40  20  10   0   0   0
Coeur d`Alene  71  48  72  48  75  48 /  60  40  20   0   0   0
Pullman        65  45  69  43  73  45 /  60  30  20   0   0   0
Lewiston       74  54  76  53  79  53 /  60  20  10   0   0   0
Colville       77  38  78  39  76  38 /  20  20  10   0   0   0
Sandpoint      70  46  72  45  73  44 /  50  50  20   0   0   0
Kellogg        66  49  67  50  72  49 /  70  60  30  10   0   0
Moses Lake     79  48  79  46  78  46 /   0  10   0   0   0   0
Wenatchee      78  55  80  53  79  53 /   0   0   0   0   0   0
Omak           83  51  82  51  81  48 /  10  10   0   0   0   0

&&

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

$$