407
FXUS66 KPDT 271112
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
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
PREV DISCUSSION... /ISSUED 958 PM PST WED NOV 26 2025/
UPDATED AVIATION DISCUSSION.
AVIATION...06Z TAFS...VARIABLE CONDITIONS ACROSS SITES, WITH VFR AT
KRDM/KBDN, MVFR AT KDLS/KYKM/KPSC, AND LIFR AT KPDT/KALW DUE TO
REDUCED CEILINGS OF .5KFT AND VISIBILITIES OF 1/4SM RESPECTIVELY.
THESE LIFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH THE
MAJORITY OF THE PERIOD AS A SYSTEM PASSES THROUGH THE REGION. KYKM
IS ALSO FORECAST TO REACH IFR CONDITIONS IN THE EARLY MORNING
HOURS DUE TO CEILINGS OF .7-.9KFT, WHICH WILL EXTEND THROUGH
THURSDAY EVENING. WINDS WILL STAY LIGHT AND BELOW 10 KTS, WITH THE
EXCEPTION OF KRDM/KBDN WHICH WILL EXPERIENCE SUSTAINED WINDS OF
10-12 KTS AND GUSTS OF 20-22 KTS LATE THURSDAY MORNING THROUGH
THE AFTERNOON ASSOCIATED WITH THE FRONTAL PASSAGE. LIGHT RAIN WILL
ALSO IMPACT ALL SITES BY LATE MORNING AND AGAIN TOWARD THE END OF
THE PERIOD. THE ONLY TERMINALS TO STAY DRY WILL BE KRDM/KBDN. 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
AVIATION...75
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