814
FXUS66 KPDT 282102
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
202 PM PDT Fri Jun 28 2024

.SHORT TERM...Tonight through Sunday night...A weak and dry westerly
flow aloft has brought another day of seasonal temperatures. Winds
are considerably less, temperatures are a few degrees warmer, and
the relative humidity is about the same or a little lower than
this time yesterday. Overall, it has been a tranquil weather day
and tonight will be quiet and mild. No major weather concerns are
anticipated this weekend, although it will be breezy to locally
windy on Sunday which raises minor concerns for fire weather.

Tomorrow, the westerly flow will back to the southwest as a
shortwave trough develops off the eastern Pacific. The trough
will move onshore Saturday night and across WA/OR on Sunday. This
will help to destabilize the atmosphere, and there will be enough
upper level support and moisture to bring a chance of mountain showers
and a slight chance of t-storms Saturday night and Sunday. The
PoPs were increased slightly Saturday night over the Blues and
Wallowas to around 30%, primarily due to the support of the left
exit region of an 80kt jet. NBM shows a 15% probability of
thunder, and CAPEs from the NBM and CAMs average around 150 J/kg
so will keep the slight chance of t-storms in the forecast. There
will be an uptick in winds Saturday, starting in the late
afternoon as the inverted surface thermal trough shifts eastward
and an onshore flow increases.

Sunday`s winds will be stronger due to a more pronounced marine
push. Forecast soundings near Puget Sound show the marine layer
as deep as 800 mb, so confidence is high that cooler air will seep
through the Cascade gaps and induce winds in the Kittitas Valley,
the eastern CR Gorge, Sisters, and other wind exposed areas in
the eastern valleys. The most likely wind gusts will be 25-35 mph
with a 20% probability of 35-40 mph gusts. RHs will not be
critically low--mostly in the 20s to mid 30s--therefore red flag
conditions are not expected (70% confidence). Showers and
t-storms will mainly develop over ID with a 20-30% chance of
convection in Wallowa County Sunday afternoon.  Wister/85


.LONG TERM...Seasonable temperatures and gusty winds will continue
through Monday as the transient trough exits the PacNW. With the
upper ridge sweeping across the region Tuesday onward, dry
conditions persist with no chance of precip across the region.
Temperatures will be above normal starting Tuesday with the ridge
building over the PacNW.

Through late Monday, gusty winds at 25-35 mph will occur around
the Cascade gaps (>70% confidence). This is due to the tightening
surface pressure gradient left behind from the passing trough.
Probability remains low to moderate (30-50%) for wind gusts
exceeding 40 mph. No Red Flag conditions have been forecasted, but
the combination of increased winds and low relative humidity in
the teens to lower 20s will raise concerns for areas of elevated
fire weather potential, including 4th of July. Tuesday onward,
winds will decrease as the upper ridge builds over the forecast
area. Breezy conditions will continue with occasional wind gusts
at around 15-25 mph through the remaining extended period.
Feaster/97


&&

.AVIATION...18Z TAFS...All sites remain VFR for this
period with current few to sct clouds. Mid to high clouds with light
winds will prevail during the next 24 hours. Feaster/97


&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  55  82  57  82 /   0  10  10   0
ALW  58  87  60  87 /   0  10  10   0
PSC  60  88  62  90 /   0  10   0   0
YKM  57  87  55  85 /   0  10   0   0
HRI  57  87  60  88 /   0  10  10   0
ELN  57  85  56  80 /  10  10   0   0
RDM  48  80  48  80 /   0  10   0   0
LGD  52  84  54  79 /   0  10  30  10
GCD  51  86  52  81 /   0  10  20  10
DLS  59  85  60  82 /   0  10   0   0

&&

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

$$

SHORT TERM...85
LONG TERM....97
AVIATION...97