590
FXUS66 KPDT 232134
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
234 PM PDT Sun Jun 23 2024

.SHORT TERM...This afternoon through Tuesday night...Dry air aloft
will continue to mix to the surface this afternoon resulting in
widespread relative humidity in the upper single digits to mid-
twenties across the lower elevations of our forecast area. In
conjunction with breezy to locally windy southwesterly to
northwesterly winds, this is producing elevated fire weather
conditions. Red Flag Warnings remain in effect for fire weather
zones OR640, OR641, and WA691 through 8PM this evening.

Winds through the Kittitas Valley will remain supportive of low-
end advisory criteria through this evening -- sustained winds of
20-30 mph with gusts of 35-45 mph are forecast. Tonight, winds
will slacken.

Monday, quieter weather returns to the region with a dry zonal
flow aloft.

Tuesday, an offshore closed low will approach the PacNW.
Meanwhile, an upper-level ridge will amplify over the northern
Rockies. The result will be a shift to southwesterly flow aloft.
Temperatures will also warm on Tuesday -- the probability of
reaching or exceeding 90 degrees for our population centers is
high (70-90%).

Tuesday night, a shortwave will eject northeastward around the
base of the closed low and usher in some low-end precipitation
chances (5-14%). There is a signal for some weak elevated
instability in numerical guidance, but confidence is currently low
(<40%) in anything more than isolated showers. Moreover,
confidence is very low (<10% chance) in lightning. Plunkett/86

&&

Long Term...Wednesday through Sunday...A trough will move over
to the PacNW starting Wednesday through Thursday, bringing
increased winds and cooler temperatures across the region.
Confidence remains low (<30%) for mountain showers at the crest of
the WA/OR Cascades due to limited moisture associated with trough
and cold front. Cooler temperatures will arrive late Wednesday
through Thursday with the arrival of the trough. However,
temperatures will then be above normal again with an arrival of
the ridge Friday through Saturday across the forecast area. Sunday
temperatures decrease by few degrees as a shortwave trough passes,
but will remain within a few degrees of normal.

Wind gusts will occur late Wednesday afternoon at 25-35 mph
through early night around the Columbia Basin, Columbia River
Gorge, Kittitas and Yakima valleys. Probability is moderate for
wind gusts exceeding to 40 mph (60%). High confidence for
increased wind gusts in these areas Thursday as well with the
trough passing. Friday through Saturday, winds will settle down
with the upper ridge building over the forecast area. Starting
late Sunday, locally windy conditions will return across the
forecast area with wind gusts at 25-35 mph before decreasing
overnight (50% probability). Feaster/97

&&

.AVIATION...18Z TAFS...VFR prevailing for this period.
KDLS/KPDT/KYKM/KALW/KPSC currently have some clouds, but clear
skies for KRDM/KBDN. As the system passes, increasing winds will
be a concern for all sites sustaining at 12-20kts with wind gusts
around 20-30kts. Wind conditions should improve later this
evening. Feaster/97

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  48  81  50  91 /   0   0   0   0
ALW  52  84  54  94 /   0   0   0   0
PSC  52  86  56  95 /   0   0   0   0
YKM  46  83  56  91 /   0   0   0   0
HRI  52  86  55  95 /   0   0   0   0
ELN  47  81  53  90 /   0   0   0   0
RDM  43  84  48  91 /   0   0   0   0
LGD  47  81  49  90 /   0   0   0   0
GCD  47  87  52  94 /   0   0   0   0
DLS  52  84  55  94 /   0   0   0   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Red Flag Warning until 8 PM PDT this evening for ORZ640-641.

WA...Red Flag Warning until 8 PM PDT this evening for WAZ691.

     Wind Advisory until midnight PDT tonight for WAZ026.

&&

$$

SHORT TERM...86
LONG TERM....97
AVIATION...97