555
FXUS66 KPDT 302344
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
344 PM PST FRI JAN 30 2026
KEY MESSAGES
- FOG RETURN OVERNIGHT INTO LATE SATURDAY MORNING.
- LIGHT MOUNTAIN RAIN OVER THE WEEKEND.
- UPPER LEVEL RIDGE BUILDS OVER INTO NEXT WEEK.
DISCUSSION
CURRENT SATELLITE AND RADAR IMAGERY SHOW A FRONTAL
SYSTEM MOVING ACROSS OUR FORECAST AREA, BRINGING LIGHT SHOWERS OVER
THE WA/OR CASCADES FIRST. OBSERVED FROM WEBCAMS AND SURFACE
OBSERVATIONS, VISIBILITIES HAVE IMPROVED TO 2SM OR HIGHER FOR
KITTITAS VALLEY EXTENDING THROUGH THE COLUMBIA BASIN OF OR/WA FROM
EARLIER. HOWEVER, PATCHY FOG MAY CONTINUE TO LINGER IN SOME
LOCALIZED AREAS. THE WEATHER FOR THE REMAINING DAY WILL BECOME QUIET
AS THE UPPER RIDGE PASSES THROUGH THE PACNW. FOG DEVELOPMENT WILL
HAPPEN OVERNIGHT INTO EARLY SATURDAY MORNING FOR COLUMBIA BASIN AND
YAKIMA/KITTITAS VALLEYS. NBM AND HREF SUGGEST A 15-30% PROBABILITY
FOR VISIBILITIES TO REACH 3SM OR LOWER, BUT CAN'T EXACTLY RULE OUT
ON THE STRENGTH AND LONGEVITY DUE TO THE MODELS BEING LOW-BIAS
WITH THE FOG. HOWEVER IF THINGS WERE TO FURTHER MATERIALIZES,
THEN DENSE FOG ADVISORIES WILL BE CONSIDERED FOR THOSE AREAS.
LIGHT MOUNTAIN RAIN WILL DEVELOP OVER THIS WEEKEND WHEN THE ANOTHER
FRONTAL SYSTEM ARRIVE TO OUR REGION, IMPACTING THE WA/OR CASCADES
AND NORTHWEST BLUES. WITH POP CHANCES AT A 40-70%, THE CASCADES MAY
GET LESS THAN A 0.10 INCH SATURDAY BUT INCREASES UP TO 0.15 INCH OR
MORE SUNDAY. SINCE SNOW LEVELS WILL BE ABOVE 4 KFT, THIS PRECIP
EVENT WILL MOST LIKELY BE RAIN-DRIVEN. IN ADDITION TO THIS, WINDS
COULD BECOME SLIGHTLY BREEZY OVER THE SOUTHERN PART OF WALLOWA
COUNTY UP TO 15-25 MPH FROM TIGHTEN SURFACE PRESSURE GRADIENTS (30-
40% CONFIDENCE). MODELS AND ENSEMBLES ARE IN GOOD AGREEMENT WITH
THIS PATTERN AND THE TIMING AS WELL.
STARTING MONDAY ONWARDS, AN UPPER RIDGE WILL BUILD OVER THE PACNW
AGAIN. LIGHT MOUNTAIN RAIN MAY LINGER ACROSS THE CASCADES AND
NORTHWEST BLUES MONDAY FROM THE INITIAL SYSTEM. THIS COULD BRING IN
QPF AMOUNTS UP TO 0.20 INCH, BUT WITH SLIGHT CHANCES (15-30%). FOG
AND AIR STAGNATION MAY RAISE SOME CONCERNS WITH THIS RIDGE, BUT
CONFIDENCE IS LOW (<20%) AT THIS TIME. FEASTER/97
AVIATION /00Z TAFS THROUGH 00Z SUNDAY/
THE FOG HAS OVERSTAYED
ITS WELCOME AND HAS LINGERED MORE THAN PREVIOUSLY FORECASTED
FROM THE 18Z TAFS. WE'VE HAD SOME DECENT MIXING WITH PDT/YKM AND
TO SOME EXTENT, DLS AND ALW. ALTHOUGH CONDITIONS REMAIN MOSTLY
MVFR OR BELOW (EXCEPT FOR BDN/RDM WHO REMAIN VFR). FOG IS
EXPECTED TO DEVELOP AGAIN OVERNIGHT IN ALL TAF SITES, EXCEPT
BDN/RDM. FOG FORECASTING FOR THIS TAF PERIOD IS EXTREMELY LOW
CONFIDENCE WITH THE FORMATION OF FOG AND THE ATMOSPHERIC MIXING
DYNAMICS AT A SORT OF "TUG-OF-WAR" BATTLE. WE'VE SEEN THIS WITH
FOG SLOSHING AROUND AND WILL CONTINUE SO THROUGH THE NEXT 24
HOURS. FOR NOW, EXPECT ANOTHER ROUND OF SUB-MVFR CONDITIONS
THROUGH TONIGHT AND TOMORROW MORNING WITH SOME LIGHT
PRECIPITATION MIXED IN AS WELL. WINDS REMAIN LIGHT AND VARIABLE.
PRELIMINARY POINT TEMPS/POPS
PDT 39 56 35 51 / 20 0 0 10
ALW 42 55 37 52 / 30 10 0 20
PSC 35 50 33 53 / 20 10 0 10
YKM 34 48 34 50 / 10 10 0 20
HRI 37 51 34 52 / 20 10 0 10
ELN 34 44 33 45 / 10 20 10 30
RDM 33 57 33 53 / 10 0 0 10
LGD 37 51 38 51 / 20 0 0 10
GCD 37 55 35 53 / 10 0 0 10
DLS 41 54 39 52 / 20 10 0 50
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...NONE.
DISCUSSION...97
AVIATION...95
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