669
FXUS66 KPDT 110532
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
932 PM PST MON NOV 10 2025
UPDATED AVIATION...06Z TAFS
VFR CONDITIONS WILL PERSIST
THROUGH THIS PERIOD FOR MOST SITES. HOWEVER, KDLS MAY FALL UNDER
MVFR AS HAZE WILL LOWER VSBY TO 4SM THROUGH THE REST OF THIS
EVENING AND THEN IFR WHEN LOW CLOUDS DEVELOP OVERNIGHT BEFORE
IMPROVING TUESDAY MORNING. LINGERING RAIN CONTINUES FOR KALW
TONIGHT BUT, CONFIDENCE IS LOW ON THE EXTENT (<30%). THANKS TO THE
MORNING FOG AND LOW CLOUDS, THIS WILL BRIEFLY BRING DOWN THE VSBY
TO A QUARTER OF A MILE OVER KPSC HENCE LIFR CONDITIONS. BUT, THE
FOG AND LOW CLOUDS SHOULD BEGIN TO DECREASE LATE TUESDAY MORNING.
OVERALL, WINDS WILL BE LESS THAN 10KTS FOR ALL SITES. FEASTER/97
PREV DISCUSSION
/ISSUED 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 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, IT’S 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
DISCUSSION...71
AVIATION...97
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