139
FXUS66 KPDT 271143
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
343 AM PST Thu Nov 27 2025

.AVIATION...12Z TAFs...Widespread fog impacts with IFR/LIFR
conditions will continue through the night. Unsettled weather
will push through the late morning to early afternoon hours,
brining rain into the TAF sites (except for BDN/RDM). Conditions
will continue to be sub VFR for the vast majority of the time,
although conditions should improve slightly for the sites as we
head into the daytime. Going forward, guidance shows the system
will keep visibilities and ceilings low through out the next 24
hours, with some visibility improvements although ceilings will
remain sub 1000 feet. Regardless, a tricky forecast is ahead with
confidence in all areas not exceeding >75% for ceilings and vis
with rain being the most confident factor that will verify.

&&

.PREV DISCUSSION... /issued 312 AM PST Thu Nov 27 2025/

DISCUSSION...

A pacific warm front was draped roughly along the Columbia River
overnight. Mid and higher level moisture lifting pole ward over
southern WA was exposing broad low level stratus and fog on the
the 10.3-3.9um GOES band. METARs and highway cams evidenced fairly
widespread dense fog across much of the central Oregon counties
into the foothills of the Blue Mountains. The dense fog advisory
was expanded to include additional areas long the northern blue
mountain foothills including Walla Walla. Impact from this fog
will include reduced visibility to less than one quarter of a mile
across much of these areas through around 18z, when the HREF
surface probabilities of vsby <1/2 and 1/4 mile fall form this
50-70% values this morning to the last lingering area of 15% or
so across Umatilla county by 10 am.

By midday the low pressure off the coast will be moving inland,
increasing pops across the WA and OR Cascades again to 80-95%.
This will lead to some additional light snow across the Washington
Cascade crest, Snoqualmie and White passes. while rain showers
farther south across the Columbia Gorge and OR cascades and around
0.05 mean rainfall across the Yakima and Kittitas valleys.
As the system progresses farther inland overnight, the eastern
mountains will likely pick up a few additional inches of snow.
The rest of the week is a relatively dry period for much of the
lowland areas. This weekend will be the coolest period of the next
7 days as highs will be relegated tot he upper 30s and lower 40s
and lows in the 20s. NBM range of outcomes show a slight
moderation to temperatures in the 40s and 50s for next week.

PREV DISCUSSION... /issued 1045 PM PST Wed Nov 26 2025/

UPDATE...

Current infrared satellite imagery and local webcams confirm the
presence of dense fog across Central Oregon, Blue Mountain
foothills of Oregon, and the John Day Basin. These conditions are
impacting the Interstate 84 and Highways 97, 11, and 19 corridors
and are not expected to improve until mid-morning. Visibilities of
lower than one quarter mile are currently being observed, so use
extra caution if traveling on the earlier mentioned
thoroughfares. A Dense Fog Advisory has been issued for these
areas until 10 AM Thursday. 75

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  46  36  44  29 /  60  90  90   0
ALW  45  38  44  31 /  70  90  90  10
PSC  45  36  49  29 /  80  90  60   0
YKM  43  36  49  29 /  90  90  40   0
HRI  45  37  47  29 /  70  90  80   0
ELN  40  32  45  26 /  90  90  30   0
RDM  55  31  50  26 /  20  30  20   0
LGD  48  36  44  27 /  40  80  90  10
GCD  53  34  46  28 /  20  30  60   0
DLS  48  41  51  37 /  90  90  70  10

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Dense Fog Advisory until 10 AM PST this morning for ORZ505-507-
     508-510-511.

WA...Dense Fog Advisory until 10 AM PST this morning for WAZ029.

&&

$$

SHORT TERM...71
LONG TERM....71
AVIATION...95