812
FXUS66 KOTX 231128
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
428 AM PDT Mon Sep 23 2024

.SYNOPSIS...

A ridge of high pressure will deliver above normal temperatures
Monday through Wednesday. A more active pattern is expected
toward midweek and beyond, with the potential for breezy
conditions and showers. Temperatures return to near normal by
Thursday.

&&

.DISCUSSION...
Monday and Tuesday: Moisture associated with a system moving into
British Columbia is spreading mid and high level clouds into the
Inland Northwest from the north as an upper level ridge begins to
shift eastward into the Pacific Northwest. Temperatures will begin
to warm on Monday with highs in the 70s to mid 80s. The ridge axis
will shift into eastern Idaho and western Montana by Tuesday
afternoon. Deep southwest flow will allow temperatures to warm
further with a 90 to 100 percent chance of temperatures above 80
degrees for most places in the Inland Northwest.

Wednesday: The ridge axis will continue to shift eastward as an
upper level trough associated with a low pressure system in the Gulf
of Alaska digs offshore the northwest US coast. The front associated
with the low as it moves into northern British Columbia is progged
to move across the Inland Northwest late Wednesday afternoon and
evening. The timing of the front will allow temperatures to warm
into the 80s with continued support by 90 to 100 percent of the
members of the National Blend of Models.

Winds will begin to pick up late Wednesday morning and peak with the
front Wednesday afternoon and evening. The NBM is giving areas such
as the Waterville Plateau, the Columbia Basin, West Plains and the
lee of the Blues over an 80 percent chance for sustained winds above
20 mph and wind gusts above 35 mph. Precipitation chances will be
low for these areas as well. PWATs will plummet from around 1.0 inch
early Wednesday to around 0.30 inches by Thursday morning. This
intrusion of dry air, combined with the stronger winds and little
precipitation, will elevate fire concerns and pick up dust around
recently worked fields. The current timing of the frontal passage
looks to keep relative humidity values above critical thresholds
Wednesday afternoon, but an early arrival would bring greater
concerns.

In addition to the winds, this front will bring a 70 to 80 percent
chance for showers across the Cascade crest and a 50 to 60 percent
for the Idaho Panhandle.  Models are showing elevated instability
ahead and with the front over the Cascades, far northeast
Washington, and the Idaho Panhandle suggests there could be stronger
cells embedded in the showers with a 15 to 25 percent chance for
thunderstorms Wednesday afternoon and evening in these areas. /vmt

Thursday through Sunday: Breezy/windy conditions looks possible
Thursday and Friday as weather disturbances pass through. A zonal
flow that lacks substantial moisture fluxing through it allows for a
cool and mostly precipitation free Thursday for most of Eastern
Washington with the exception being minor chances of light showery
precipitation over North Idaho and within close proximity of the
Cascade Crest. This is followed up with another disturbance passage
however this feature has a more adequate moisture feeding into it as
it passes through Thursday night into Friday morning. The remainder
of the weekend the airmass looks rather dry as a general weak and
broad trof lingers with weak disturbances possibly moving thru it so
some very spotty precip mentions show up mainly close to the British
Columbia Border while cloud cover remains rather sparse. As far as
temperature trends go there looks to be generally a 15 to near 20
degree drop in high temperatures Thursday compared to those of
Wednesday with a gradual warming trend peaking either Thursday or
Friday depending on the location that is followed up with slight
cooling after. /Pelatti

&&

.AVIATION...
12Z TAFS: VFR conditions. Bands of mid and high clouds will
continue to stream in from the north through the early morning and
start to decrease in coverage after 18Z. There is a 15 percent
chance for light showers over the Cascades through 15Z.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence
for VFR conditions at all TAF sites.

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        78  51  86  58  87  49 /   0   0   0   0  10  40
Coeur d`Alene  76  51  83  57  85  51 /   0   0   0   0  10  40
Pullman        73  50  83  55  84  48 /   0   0   0   0  10  40
Lewiston       81  57  90  62  91  57 /   0   0   0   0  10  40
Colville       79  43  84  45  85  40 /   0   0   0   0  10  40
Sandpoint      73  48  79  53  81  48 /   0   0   0   0  10  50
Kellogg        71  53  82  61  82  53 /  10   0   0   0  10  50
Moses Lake     82  53  87  55  86  46 /   0   0   0   0  10  20
Wenatchee      83  61  86  61  82  51 /  20   0   0   0  20  30
Omak           85  56  87  58  86  47 /   0   0   0   0  10  20

&&

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

$$