929
FXUS66 KPDT 121133
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
333 AM PST Thu Feb 12 2026

Updated Aviation Discussion

.DISCUSSION...
Mostly quiet conditions across the forecast area
tonight as a ridge of high pressure sits overhead. Of note,
however, is an area of stratus meandering across portions of
Crook and Deschutes county, and the first hint of fog beginning
to develop along the Columbia River north of the Tri-Cities. In
fact, traffic cameras and the Richland airport indicate patchy
dense fog has developed in portions of the western Tri-Cities
already. Through the remainder of the morning, the expectation
is that fog/low stratus will continue to develop across
portions of the WA Columbia Basin, as well as in other sheltered
areas in the lower elevations.

Today through early Friday: Upper level ridging will continue to
sit over the forecast area throughout today and into early
Friday. Dry conditions and light winds will prevail under the
high pressure aloft, however, this will also allow for patchy
areas of fog/low stratus to develop across portions of central
OR, the eastern Gorge, the Lower Columbia Basin, and adjacent
foothills/valleys.

Friday through Sunday: Friday will mark the beginning of a
period of active weather across the the forecast area that will
persist into next week. By Friday afternoon, ensemble cluster
solutions show a trough dropping out of the Gulf of Alaska with
the main low circulation passing PacNW to the west. This trough
will continue it`s journey south and setup offshore central CA
by late Sunday afternoon, with the trough becoming a closed low
(confidence 55-75%). Trends over the past several forecast
cycles have been for this trough to remain offshore during it`s
weekend transit, with minimal moisture support for the PacNW.
This has resulted in a downtrend in snow amounts across the
mountains through the weekend, with mod-high confidence (55-80%)
that snow amounts over the three day period will be 2 to 6
inches, with low confidence (20%) in 72-hr snow accumulation
amounts exceeding 6 inches in any of our passes. Meanwhile, the
lower elevations are expected to see their best chance of
precipitation Saturday, which will consist of mostly rain during
the day (confidence 60-75%), while a light rain/snow mix may
develop over central OR Saturday night (confidence 50-60%).
Otherwise, conditions will dry out for the lower elevations
Sunday as the low dips further south (confidence 50-70%).

Monday through Wednesday: Ensemble guidance starts in good
agreement Monday with a second upper trough diving south out of
the Gulf of Alaska and setting up between 40N and 50N Monday
into Tuesday. However, disagreement arises between the ensemble
members on the position, timing, and evolution of the trough the
latter half of Monday through Tuesday. The two main solutions
presented by ensemble cluster solutions are a trough that stays
offshore through Tuesday, resulting in light to moderate snow
accumulations across the mountains; or a trough that crosses
inland during this period, resulting in moderate to locally
heavy snow accumulations in the Cascades and northern Blues.
The former solution is currently favored by a majority of
ensemble members at this time, and would still result in
impactful winter weather conditions through the passes. Other
than winter weather concerns, the NBM shows a return of breezy
winds (gusts 25-40mph) to the region, with a 40-65% chance of
gusts greater than 35mph developing in the lower elevations
Tuesday.

By Wednesday, ensemble members agree in the PacNW continuing to
be impacted by an upper trough, however disagreement remains in
timing of impacts as well as the strength/position of the
trough. That said, confidence is at least moderate (35-55%) in
mountain snow and light rain and/or rain/snow mix across the
lower elevation zones Wednesday. Lawhorn/82

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...VFR conditions to
mostly prevail through the period. There is a less than 15%
chance of low CIGS/vsby developing at site DLS, so have removed
mention this TAF period. Fog has been developing around the
Tri-Cities, but has been moving around throughout the night.
Decided to include a tempo group for site PSC to with vsby
lowered to 3SM, though vsby could decrease further at times.
Otherwise, VFR CIGs/vsby are expected at all other sites through
the period. Winds will be light, 12kts or less. Lawhorn/82


&&

.Preliminary Point Temps/PoPs...
PDT  33  50  36  48 /   0   0  20  30
ALW  35  49  39  49 /   0   0  30  40
PSC  31  50  36  51 /   0   0  10  10
YKM  30  46  31  47 /   0   0  10  10
HRI  31  50  36  50 /   0   0  20  20
ELN  30  43  30  42 /   0  10  20  10
RDM  24  49  29  45 /   0   0   0  30
LGD  29  49  34  48 /   0   0  30  60
GCD  28  51  33  48 /   0   0  10  50
DLS  35  48  37  48 /   0  10  40  40

&&

.Preliminary Point Temps/PoPs...
PDT  33  50  36  48 /   0   0  20  30
ALW  35  49  39  49 /   0   0  30  40
PSC  31  50  36  51 /   0   0  10  10
YKM  30  46  31  47 /   0   0  10  10
HRI  31  50  36  50 /   0   0  20  20
ELN  30  43  30  42 /   0  10  20  10
RDM  24  49  29  45 /   0   0   0  30
LGD  29  49  34  48 /   0   0  30  60
GCD  28  51  33  48 /   0   0  10  50
DLS  35  48  37  48 /   0  10  40  40

&&

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

&&

$$

DISCUSSION...82
AVIATION...82