Area Forecast Discussion
Issued by NWS Spokane, WA

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FXUS66 KOTX 031134
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
435 AM PDT Wed Jun 3 2020

.SYNOPSIS...
Mild and dry weather is expected through Thursday. Chances for
showers will increase late on Friday as a slow moving weather
system spreads moisture into the Pacific Northwest. The weekend
will be cooler than average with a good chance showers and breezy
at times, which looks to linger into early next week.

&&

.DISCUSSION...
Today through Thursday night: Westerly flow continues over the
region today with the jet stream aloft moving higher level
moisture over the Pacific Northwest in the form of high cloud
thickening this afternoon and evening. Continued cloud cover and a
small cooling of the air mass will drop temperatures a degree or
three today. Winds will increase again along the east slopes of
the Cascades and spread east into the Central Basin with gusts to
25 to 30 mph on average late afternoon and evening. These winds
will stretch as far east as Mattawa, George, Quincy, Palisades and
Waterville on the Waterville Plateau. Going into Thursday there
looks to be enough moisture along with a weak disturbance tracking
across southern British Columbia Canada to have a small chance
for light showers along the Canadian border mountains.
Temperatures will be 1 to 3 degrees warmer Thursday. TC

Friday: This will be our transition day from our current mild and
dry weather regime to a showery and cooler pattern. The majority
of Friday looks to be pleasant with above average temperatures and
relatively light winds, but a broad trough organizing off the
coast will spread an abundance of clouds across the Inland
Northwest during the day. The influx of moisture in the afternoon
and evening should result in an increase of showers. At this time,
the majority of the models delay most of the shower activity until
Friday evening. There is decent agreement that clusters of showers
will develop across north central Oregon and across the eastern
third of Washington in the evening and migrate into the Idaho
Panhandle overnight into Saturday morning. Some thunderstorms may
be embedded within the clusters of showers, but convection does
not look strong. This is a much different system than what we saw
last weekend. Friday`s trough and frontal system will arrive much
slower and the air mass ahead of the front won`t be as hot and
unstable.

Saturday through Monday: Afternoon temperatures this weekend into
Monday will be about 10 degrees below average as a broad and slow
moving trough languishes over the Pacific Northwest. The medium
range models don`t produce much precipitation across central
Washington Sat, Sun or Mon where we need it the most. The most
generous rain amounts are expected over the Idaho Panhandle
Saturday with our initial frontal surge and then again Monday
under a potential deformation band as the upper low pivots into
Montana. Seasonably breezy conditions are expected through the
weekend into Monday with 15 to 20 mph winds common across the
Columbia Basin, Palouse, Wenatchee area, and West Plains as cool
air spills over the Cascades into central and eastern Washington.

Tuesday: Forecast confidence for Tuesday is low at this time. Our
weekend trough is expected to eject into the Northern Plains by
Tuesday. The GFS, GFS Ensemble Mean and Canadian models suggest
that Tuesday will be mainly dry under a shortwave ridge, but the
ECMWF is considerably wetter with a frontal system arriving
quicker with more moisture than the others. The NWS blend of
models produces low chances for showers over much of the Inland
Northwest. /GKoch

&&

.AVIATION...
12Z TAFS: All TAF sites will remain VFR through 12Z Thursday.
Expect variable high cirrus through the day Wednesday with
increasing middle level cloud generally after 03Z across the eastern
third of Washington and Idaho Panhandle. Gusty wind will return to
KGEG in the afternoon with gusts to 15-20 KTS. Stronger gusts around
25 to 30 KTS at KEAT in the early evening hours. These gusty winds
will extend from KEAT to the east into the Waterville plateau and
lower Central Basin area into late evening. TC


&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        70  49  72  47  74  52 /   0  10   0   0  10  50
Coeur d`Alene  70  49  71  47  75  52 /   0  10   0   0  10  50
Pullman        69  48  69  47  74  50 /   0   0   0   0  10  50
Lewiston       77  54  76  53  81  57 /   0   0   0   0  10  50
Colville       75  47  75  46  76  51 /   0  10   0   0  20  50
Sandpoint      70  51  70  48  73  53 /   0  10  10   0  20  60
Kellogg        69  50  68  48  75  53 /   0  10   0   0  20  60
Moses Lake     78  49  79  51  80  52 /   0   0   0   0  10  30
Wenatchee      77  51  76  53  76  54 /   0   0   0   0  10  30
Omak           76  47  76  50  76  53 /   0   0   0   0  10  30

&&

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

&&

$$



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