941
FXUS66 KPDT 191040 CCA
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
240 AM PST WED NOV 19 2025
UPDATED AVIATION DISCUSSION
DISCUSSION
SKIES ARE CLEARING ACROSS MUCH OF THE FORECAST AREA
EARLY THIS MORNING AS A RIDGE OF HIGH PRESSURE ACCOMPANIED BY
COLD AND DRY AIR SLIDES INTO THE PACNW. LOW CLOUDS ARE LINGERING
(AND EVEN BUILDING) ACROSS SOME OF OUR ELEVATED VALLEYS IN CENTRAL
AND EASTERN OREGON, BUT OTHERWISE MUCH OF THE BASIN AND MOUNTAIN
FOOTHILLS ARE SEEING CLEAR SKIES. COULD SEE PATCHY FOG DEVELOP
ACROSS SOME OF OUR USUAL FOG-PRONE AREAS ALONG RIVER VALLEYS, BUT
GIVEN THE LACK OF A TEMPERATURE INVERSION PRESENT ACROSS OBS,
THINKING IS THAT THIS MORNING WILL JUST BE COLD, WITH MUCH OF THE
FORECAST AREA SEEING BELOW-FREEZING TEMPS. AS OF THIS DISCUSSION'S
WRITING, THE FREEZE WARNING IN THE COLUMBIA RIVER GORGE IS
FLIRTING WITH VERIFICATION WITH TEMPS IN THE MID TO UPPER 30S, AND
AS LONG AS LOW STRATUS DOES NOT FORM VIA LIGHT EASTERLY WINDS,
THE LAST OF OUR FREEZE-ELIGIBLE ZONES SHOULD FINALLY FALL.
LOOKING AHEAD, WEDNESDAY WILL BE DRY BEFORE OUR FORECAST AREA IS
CLIPPED BY THE NEXT SYSTEM - A LOW DIVING TO OUR SOUTH AND EAST
BEFORE SETTLING OVER SOUTHERN CALIFORNIA. THE TRAJECTORY OF THIS
SYSTEM IS NOT FAVORABLE FOR WIDESPREAD PRECIP, SO AS OF NOW, THE
FORECAST FOR LATE WEDNESDAY INTO THURSDAY LOOKS TO BE THAT OF LIGHT
MOUNTAIN SNOW GENERALLY LESS THAN AN INCH ABOVE PRIMARILY 4500-5000
FT, WITH PERHAPS A STRAY SHOWER IMPACTING THE BASIN (15-30%) VIA
WRAPAROUND MOISTURE FROM THE LOW AS IT DIGS TO OUR SOUTH. BUT WITH
MOST OF THIS SYSTEM'S MOISTURE LANDING TO OUR WEST, IMPACTS ARE
OVERALL ANTICIPATED TO BE MINIMAL.
WE ENTER ANOTHER RELATIVELY BENIGN PATTERN FRIDAY THROUGH SUNDAY AS
RIDGING, SLIGHTLY DIRTY IN NATURE, PREVAILS OVER THE REGION.
GUIDANCE FAVORS PERSISTENT SHOWER CHANCES ACROSS PRIMARILY THE WA
CASCADES OVER THE WEEKEND, BUT QPF IS ONCE AGAIN MINUSCULE. ENSEMBLE
GUIDANCE STARTS TO DIVERGE MONDAY ONWARD, BUT SOME MEMBERS DO DEPICT
AN UPPER-LEVEL WAVE MOVING DOWN FROM THE RIDGE UPON US EARLY MONDAY
MORNING, WHICH WOULD PROVIDE FOR THE NEXT-BEST CHANCE FOR AREA-WIDE
PRECIP. BUT BEYOND THAT, FORECAST CONFIDENCE WEAKENS (30-40%) AS
ENSEMBLE SOLUTIONS DIVERGE IN LIGHT OF A RELATIVELY PROGRESSIVE
SYNOPTIC PATTERN. 74
AVIATION...12Z TAFS
MOSTLY VFR CONDITIONS FORECAST THROUGH THE
PERIOD. CHANCES OF FOG/LOW STRATUS DEVELOPING AT ANY SITE TONIGHT IS
15% OR LESS, THOUGH THAT SAID A FEW DECKS OF STRATUS ARE BEGINNING
TO DEVELOP AROUND SITE PDT PER SATELLITE. WILL CONTINUE TO MONITOR
FOR POTENTIAL IMPACTS. OTHERWISE, A SYSTEM ARRIVING TO THE REGION
WILL INCREASE MID LEVEL CLOUD COVER TO BKN-OVC BETWEEN 5KFT TO 12KFT
AGL AROUND OR AFTER 03Z AT ALL SITES, WITH A POTENTIAL FOR A
RAIN/SNOW MIX AND MVFR OR LOWER CIGS/VSBY DEVELOPING AT SITES
RDM/BDN AROUND 09Z TOMORROW. WINDS WILL REMAIN LIGHT, 12KTS OR LESS,
THROUGH THE PERIOD. LAWHORN/82
PRELIMINARY POINT TEMPS/POPS
PDT 48 32 47 32 / 0 20 30 0
ALW 48 35 46 36 / 0 20 40 10
PSC 49 32 49 30 / 0 10 10 0
YKM 48 32 50 29 / 0 20 10 0
HRI 48 34 48 31 / 0 20 20 0
ELN 45 29 48 29 / 0 20 10 10
RDM 50 28 47 23 / 0 60 20 0
LGD 50 34 50 30 / 0 20 50 10
GCD 53 35 49 29 / 0 30 40 0
DLS 50 39 52 36 / 0 60 40 10
PDT WATCHES/WARNINGS/ADVISORIES
OR...FREEZE WARNING UNTIL 10 AM PST THIS MORNING FOR ORZ041.
WA...FREEZE WARNING UNTIL 10 AM PST THIS MORNING FOR WAZ024.
DISCUSSION...74
AVIATION...82
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