116
FXUS66 KPDT 070535
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
935 PM PST Thu Nov 6 2025

Updated Aviation Discussion

.AVIATION...06z TAFs...VFR conditions expected. Shower activity
will taper off overnight, mainly for DLS, PDT, and ALW, before
skies clear and winds remain moderately breezy through the period.
By Friday morning, expect few-sct mid to high clouds, with W/NW
winds gusting up to 25 kts at times, before decreasing through
the remainder of the day into Friday evening. 74

&&

.PREV DISCUSSION... /issued 234 PM PST Thu Nov 6 2025/

DISCUSSION...

Key Messages:

1. Wet and breezy to windy this evening into Friday

2. Mostly dry late Friday into the middle of next week

3. Timing uncertainty in weather system late next week

Afternoon satellite imagery shows a closed low tracking northeast
into the northern end of Vancouver Island, with a surface cold
front extending from Vancouver Island to offshore of NW CA.
Aloft, a shortwave is evident west of the OR/WA coast. The
shortwave and surface cold front will come onshore later this
evening through the overnight hours, ushering in widespread
precipitation and breezy to windy southwesterly then westerly
winds. Regarding wind potential, the 12Z HREF, NAM, and GFS all
place a 8-12 hPa pressure difference across the region from PDX to
GEG, along with a 40-50 kt low-level jet over the Columbia
Plateau. If frontal passage were during the daytime with a well-
mixed boundary layer, this would be enough to warrant a Wind
Advisory for much of the lower elevations. That said, due to the
nocturnal nature of the event, have opted to hold off on issuing
any wind highlights for cold frontal passage due to barely
insufficient (50-70 percent) confidence in a short period (1-4
hours) of advisory-level gusts (45-55 mph for wind-prone
locations within the eastern Columbia River Gorge, lower Columbia
Basin, north-central Oregon, and the foothills of the Blue
Mountains. Confidence is very high (70-95 percent) in widespread
gusts of 30-40 mph for the aforementioned areas.

While mountain snow is forecast tonight into Friday morning as
snow levels drop behind the cold front, only light amounts (1 inch
or less) are forecast for mountain passes, except for White Pass
in WA which is forecast to receive 3-5 inches of snow overnight.

Upslope showers will persist along the Cascade crest and perhaps
the highest terrain of the northern Blue Mountains through much
of Friday, with otherwise dry conditions across the forecast
area. Breezy to locally windy westerly winds are forecast through
the Cascade gaps until mid-afternoon Friday when pressure
gradients relax.

Dry weather is forecast late Friday through the weekend as an
upper-level ridge of high pressure builds overhead (95 percent
confidence). May (60 percent confidence) see the return of some
fog in low-lying spots of the lower elevations Saturday and
Sunday, especially during the morning hours.

Late Monday, there is medium-high (30-70 percent) confidence in a
weak shortwave tracking across the Pacific Northwest. This wave
would produce some light precipitation (trace to a couple tenths
of an inch) along the Cascade crest and highest elevations of the
northern Blue Mountains. Best chances (50-70 percent) for
precipitation will be along the WA Cascade crest, with lowest
chances (15-30 percent) for the northern Blue Mountains.

Looking ahead, clusters of ensemble members indicate significant
uncertainty in the evolution of an offshore closed low in the
Wed/Thu time period of next week. As of the 12Z ensemble runs, dry
conditions are favored (70 percent or more of ensemble members)
Tuesday through Wednesday, with a return of precipitation more
likely by the Thu/Fri period as ensemble mean 500-hPa fields show
the trough moving over the Pacific Northwest.

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  40  55  32  54 /  90  10   0   0
ALW  43  54  36  53 / 100  20   0   0
PSC  42  58  30  51 /  90   0   0   0
YKM  36  56  30  52 /  90   0   0   0
HRI  42  58  32  52 /  80  10   0   0
ELN  34  50  28  48 / 100  10   0   0
RDM  34  52  26  59 /  80  10   0   0
LGD  38  52  29  54 / 100  40   0   0
GCD  40  52  29  59 /  90  40   0   0
DLS  43  57  37  55 / 100  30  10   0

&&

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

$$

SHORT TERM...86
LONG TERM....86
AVIATION...74