581
FXUS66 KPDT 092055
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
155 PM PDT Wed Jul 9 2025

.SHORT TERM...Tonight through Friday...Satellite imagery this
afternoon shows a cold front passing over western WA and
northwestern OR, while small cumulus fields are starting to
develop along the higher terrain of the eastern mountains.

Today, an upper trough with an attendant cold front will continue
to sweep across the PacNW and exit the region by tonight.
Convective activity will pick up ahead of the trough axis through
this afternoon, with any developing storms tapping into modest
surface instability and low level lapse rates, allowing for
isolated thunderstorms to develop mainly across the higher terrain
of Grant, southern Union, and Wallowa counties. The best chances
are going to be just south of Grant county, where a Red Flag
Warning is in effect through this evening. In the lower
elevations and through the Cascade Gaps, the approach and
subsequent passage of the cold front will result in breezy to
locally gusty conditions developing this afternoon and evening.
The strongest winds (20-30mph with gusts up to 45mph) will develop
through the Cascade gaps and persist into this evening. The
Columbia Basin will also see winds around 20-25mph with gusts up
to 40 mph, with a Red Flag Warning in effect through this evening
as winds are strong enough to overcome the impacts from relatively
higher RHs this afternoon.

Tomorrow, the upper trough will be well east of the region, with
a weak northwest flow aloft. Conditions will remain cool but dry
across the forecast area with breezy conditions through the
Cascade gaps. Thursday evening through Friday, transient ridging
will slide into the PacNW, with a warming and drying trend that
will last into into early next week. Lawhorn/82

.LONG TERM...Saturday through Wednesday...Behind the exit of a
transient ridge early Saturday, broad upper ridging will develop
over the northeast Pacific and extend into the PacNW. Ensemble
cluster solutions are in great agreement of this upper ridge
sticking around the area through the middle of next week, though
agreement decreases Tuesday into Wednesday as to where the ridge
axis will be positioned. Otherwise, the only other feature to
note will be a shortwave trough attempting to ride over the upper
ridge Sunday, which could bring increased breezy conditions
through the Cascade gaps.

Overall confidence is mod-high (65-80%) that dry conditions will
prevail through the extended forecast with a warming trend into
the weekend. Locally breezy winds will develop in the afternoons
(confidence 60-80%), with strongest winds on Sunday with the upper
trough passage (confidence 50-70%). Confidence wanes into the
middle of next week with the forecasted temperatures (confidence
30-60%) owing to disagreement on the position of the ridge axis.
Lawhorn/82

&&

.AVIATION...Previous Discussion...18Z TAFs...VFR conditions to
prevail through the period. A cold front passing through the area
will bring some occasional few-bkn cloud decks above 10kft AGL
through this evening. Winds will increase to 12-20kts with gusts
to around 25kts at sites RDM/BDN/YKM/ALW/PSC this afternoon,
becoming 12kts or less after 4Z-5Z. At sites DLS/PDT, winds will
be increasing to 17-25kts with gusts up to 35kts this afternoon,
with winds decreasing to around 12kts at site PDT by 8Z, and winds
12-20kts with gusts to around 30kts at site DLS after 4Z.
Lawhorn/82


&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  60  87  58  92 /   0   0   0   0
ALW  64  87  62  92 /   0   0   0   0
PSC  61  90  58  94 /  10   0   0   0
YKM  59  87  60  93 /  10   0   0   0
HRI  62  90  59  95 /   0   0   0   0
ELN  59  82  57  92 /  10   0   0   0
RDM  50  85  48  88 /   0   0   0   0
LGD  57  82  56  87 /  10   0   0   0
GCD  54  85  52  88 /  20   0   0   0
DLS  62  84  61  94 /  10   0   0   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Red Flag Warning until 10 PM PDT this evening for ORZ691.

     Red Flag Warning until 11 PM PDT this evening for ORZ698.

WA...Red Flag Warning until 10 PM PDT this evening for WAZ691.

&&

$$

SHORT TERM...82
LONG TERM....82
AVIATION...82