520
FXUS66 KPDT 110313
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
713 PM PST Mon Nov 10 2025

.EVENING UPDATE...Current satellite and radar imagery show light
rain continuing to move out of the area as cloud coverage
gradually increases. Due to stagnant air conditions, an Air
Quality Advisory has been issued this evening through Wednesday
afternoon for Deschutes County. Otherwise, no further changes were
made to the forecast. Feaster/97

&&


.PREV DISCUSSION... /issued 300 PM PST Mon Nov 10 2025/

.UPDATED AVIATION...00Z TAFs...VFR conditions are forecast for
all sites through the forecast period. CIGs will lower through the
period as the front continues overhead, with a 20-30% chance of
light rain at PDT/ALW/PSC with chances of rain being less than 20%
at the remaining sites. MVFR CIGs are current at DLS and are
expected to remain into the overnight hours with 70% confidence,
all other sites remain low in confidence for sub-VFR. VIS will
remain P6SM across all sites through the majority of the period
with only DLS seeing sub P6SM in the early morning hours. Winds
will be mostly 10 kts or less. 90


.PREV DISCUSSION... /issued 106 PM PST Mon Nov 10 2025/

.DISCUSSION...

1. Breezy winds weakening late This Afternoon.

2. Mountain/foothills showers today, widespread Wednesday onward.

3. Pass level snow Thursday through the weekend.

Although local winds are not firmly in the wind advisory range,
breezy to gusty conditions will probably persist through the
middle of the afternoon in the Grande Ronde Valley as the surface
pressure gradient between Meacham and Baker is well agreed up by
the NAM and the NCEP SREF ensemble mean in the 6 to 6.5 range. A
significant weakening of the gradient looks imminent, and due to
the approaching surface cold front late early Today and passing
into SE OR and central ID this evening. Rain was occurring This
Afternoon along the cold front with probably some orographic lift
near KSMP with a broken band of rain extending into central and
northeast Washington. HREF PMMs show this activity spreading south
along the Washington into the Oregon Cascades this evening while
the eastern band develops southeastward dissipating across the
northern Blue Mountains. The mild temperatures forecast this
afternoon will be knocked down about 5 to 7 degrees in the
Columbia Basin for Tomorrows highs, following the cold front
moving though Tonight.

An AR will bring strong southerly 850 mb jet into central Oregon
with an IVT anomaly mid week, as a mid and upper level low
meanders onshore into western Washington Thursday night, lifting a
warm front northward across the region, setting up westerly flow
along the Cascade Caps. Pass level snow is possible for Santiam
Pass along US highway 20. The latest minor adjustments to the NBM QPF
and snow ratios/snow levels still produce about 6 inches total
snowfall over the pass area for a 2 day stretch Friday and
Saturday which is about an inch over the minimum for the local winter
weather advisory criteria. Additionally the White Pass along WA
highway 12 was coming in with an NBM mean of around 7+ inches near
the pass area, also above the lower bound for winter weather
advisory criteria. Snow load appears to be the more significant
impact as the snow ratios will be low, i.e. rain mixed with snow
and turning to all snow overnight Thursday night, with real
impacts for the pass levels by Friday morning. The snow levels
show large uncertainty to the the higher side as well, meaning the
outliers are on the side of less snow than more or longer
duration snow potential. Given the uncertainty and far out timing
at this point, its just a nod to the possibility for winter
weather advisories possibly being needed by mid to late week. At
this point the WSSI (winter storm severity index) is printing
minor impacts starting overnight Thursday and maximizing at 60%
chance of occurrence by midday Friday, which is inherently
unfavorable for any moderate impacts at all. Russell/71

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  42  57  39  55 /  20   0   0  10
ALW  44  56  42  55 /  30   0  10  10
PSC  34  52  37  53 /  10   0  10  10
YKM  33  55  38  53 /   0   0  10  20
HRI  39  55  40  53 /  10   0   0  10
ELN  32  51  35  49 /   0   0  10  30
RDM  35  64  40  65 /   0   0   0  10
LGD  42  63  45  63 /  20   0   0  10
GCD  38  66  43  66 /   0   0   0  10
DLS  43  57  44  55 /  10   0  10  30

&&

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

$$

EVENING UPDATE...97
SHORT TERM...90
LONG TERM....90
AVIATION...71