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000
FXUS66 KPDT 030931
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
231 AM PDT Wed Jun 3 2020

.SHORT TERM...Today through Friday night...It will be relatively
quiet through Thursday night as the region remains under a dry
westerly flow aloft. A fairly tight cross-Cascade gradient
combined with winds aloft will cause breezy winds through the
Cascade gaps, including the eastern Columbia River Gorge and the
Kittitas Valley. Today will have a little more cloud cover
compared to yesterday, and afternoon temperatures will be near to
slightly cooler than yesterday. Very little change in temperatures
can be expected on Thursday.

The westerly flow will back to the southwest Thursday night as an
upper low off the Gulf of Alaska dives southward. On Friday and
Friday night, the deep low will travel south along the B.C. coast,
forming an elongated trough offshore. The trough will push a
couple of embedded waves east of the Cascades that will bring
showers to the forecast area. Some of the showers could bring
0.1-0.25 inch, especially over central and northeast OR and far
southeast WA where a surface cold front remains parallel to the
upper flow with limited movement. The air mass will be unstable
for isolated to scattered thunderstorms over the eastern
mountains/valley. A 65 knot jet at H5 will provide significant
shear for possible organized convection. However, mostly cloudy
skies in the morning and afternoon may limit the surface heating
and thunderstorm activity. Wister

.LONG TERM...Saturday through Tuesday. Cold upper low pressure
system approach the Oregon/Washington coast Saturday with southwest
flow across the forecast area with showers across much of the area
and thunderstorms from central Oregon northeast through the Blue
Mountains and Wallowa County.  The low will continue to move east
through Oregon Saturday night and is then expected to track
northeast into Idaho Sunday with moisture wrapping back around
northeast Oregon and southeast Washington.  The GFS continues to be
the strongest with the low and rain amounts with heavy rain from
northwest Grant County through Wallowa county with amounts from. 1
to 1.50 inches on Sunday into Monday.  The other deterministic models
and ensembles show much less precipitation with the heaviest amounts
further east into Idaho. We will continue to assess this with
further model runs as the timeframe gets closer.  This system will
also bring some cold air into the area with snow level Sunday night
and early Monday ranging from 4500 feet along the Cascades to 5500
over the Blue Mountains.  Elevations above 5500 feet could see
several inches.  As the low moves further east Monday night, showers
will be ending with mainly dry conditions for Tuesday. There will be
cold overnight lows both Sunday night and Monday night from central
Oregon through the Blues, with areas of frost and freezing
temperatures. Temperatures will be below normal through the weekend
and early next week with highs in the 60s to around 70, with 50s in
the mountains.  Lows in the 40s with mainly 30s mountains. 93


&&

.AVIATION...12 Tafs. VFR conditions are expected through the period.
sct-bkn mid and high level clouds will continue through the period.
with winds generally under 10kts. 93


&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  78  51  76  51 /   0   0   0   0
ALW  79  52  78  53 /   0   0   0   0
PSC  81  55  80  56 /   0   0   0   0
YKM  79  49  77  53 /   0   0   0   0
HRI  80  53  79  55 /   0   0   0   0
ELN  74  49  73  48 /   0   0   0   0
RDM  80  45  77  47 /   0   0   0   0
LGD  75  48  72  49 /   0   0   0   0
GCD  78  48  75  52 /   0   0   0   0
DLS  79  52  77  54 /   0   0   0   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
&&

$$

85/93/93