648
FXUS66 KPDT 130946
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
146 AM PST THU NOV 13 2025
DISCUSSION
THE FORECAST AREA FINDS ITSELF CAUGHT BETWEEN A CUTOFF
LOW TO OUR SOUTH AND AN UPPER-LEVEL TROUGH TO OUR NORTH THIS
MORNING, WHICH WILL RESULT IN SOME MODERATELY BREEZY DOWNSLOPE WINDS
AND A ROUND OF LIGHT PRECIPITATION. LOW CEILINGS AND EVEN DENSE FOG
CONTINUE TO PERSIST FOR MUCH OF THE COLUMBIA BASIN AND THE WALLA
WALLA VALLEY, RESPECTIVELY, AS PERSISTENT COLD POOLING FROM AN
OTHERWISE STABLE SYNOPTIC PATTERN HAS ALLOWED THESE CONDITIONS TO
PERSIST. THE EXPECTATION IS THAT WE'LL SEE SOME RELIEF TODAY,
HOWEVER, AS EVEN THOUGH THE WIND FORECAST ACROSS GUIDANCE IS SUBDUED
BECAUSE OF AN OVERLY STABLE ENVIRONMENT IN THE BASIN, WARM AIR
ADVECTION BROUGHT ABOUT BY THE LOW TO OUR SOUTH AND ITS SUBSEQUENT
DOWNSLOPE WINDS SHOULD PROVIDE ENOUGH OF A DRYING EFFECT TO AT LEAST
PARTIALLY LIFT CEILINGS, ESPECIALLY ALONG THE FOOTHILLS. SO EVEN
THOUGH CENTRAL OREGON AND THE FOOTHILLS OF THE BLUES WILL SEE GUSTS
IN THE 20-30 MPH RANGE TODAY WHILE THE LOWER ELEVATIONS CONTINUE TO
SEE LIGHT WINDS, CONDITIONS ARE RIPE FOR AT LEAST SOME SCOURING OUT
OF THIS PESKY FOG AND STRATUS.
WITH MOISTURE ADVECTION LACKING, HOWEVER, PRECIPITATION IMPACTS ARE
EXPECTED TO BE MINIMAL WITH THIS SYSTEM. CAMS GENERALLY DEPICT
BROKEN SHOWER ACTIVITY OVER THE FORECAST AREA DURING MUCH OF THE
DAY, WITH MORE PERSISTENT BANDS OVER PRIMARILY THE CASCADES. BUT
WITH SNOW LEVELS WELL ABOVE 7000 FT, PTYPE WILL BE RAIN ACROSS ALL
OF OUR AREA'S MOUNTAIN PASSES. LIGHT SHOWER ACTIVITY MAY PERSIST
ACROSS THE MOUNTAINS THROUGH FRIDAY (30-40% CONFIDENCE), HOWEVER THE
BULK OF THE MOISTURE WITH THIS ONCOMING SYSTEM IS EXPECTED TO OCCUR
TODAY, BEFORE TRANSITORY RIDGING SLIDES IN LATE FRIDAY INTO
SATURDAY.
WIDESPREAD POPS RETURN ON SUNDAY AS GLOBAL MODELS GENERALLY DEPICT A
WEAK SHORTWAVE CLIPPING THE FORECAST AREA TO THE EAST, BUT AGAIN
WITH ONLY MINIMAL PRECIP IMPACTS, CONCENTRATED MAINLY ACROSS THE
EASTERN MOUNTAINS WHERE SNOW LEVELS ARE GENERALLY EXPECTED TO BE
ABOVE THE 6000-7000 FT RANGE. COLDER AIR THEN LOOKS TO INTRUDE ON
MONDAY AS A MORE NORTHWESTERLY TROUGH MOVES IN, BUT THIS SYSTEM
LOOKS TO BE RELATIVELY MOISTURE-STARVED BASED ON ENSEMBLE QPF
GUIDANCE. BETTER, MORE WIDESPREAD POPS MATERIALIZE LATE TUESDAY INTO
WEDNESDAY AS ENSEMBLES GENERALLY DEPICT A MORE ORGANIZED TROUGH
MOVING INTO THE PACNW. 74
AVIATION...06Z TAFS (PREVIOUS DISCUSSION)
WHILE MOST SITES ARE
CURRENTLY IN VFR, KALW WILL BE IN LIFR FROM THE LOW CLOUDS.
TONIGHT'S CONCERN WOULD BE FOG/MIST AND LOW CLOUDS, WHICH MAY
BRING VSBYS AND/OR CIGS DOWN MAINLY FOR KALW. BUT, WILL CONTINUE
MONITORING FOR OTHER SITES IN CASE THE FOG/MIST DEVELOPS. AS THE
FRONTAL SYSTEM ARRIVES THURSDAY, WIDESPREAD RAIN SHOWERS WILL
DOMINATE ALL SITES THROUGH THE DAY ALONG WITH MIST. THIS COULD
ALSO POTENTIALLY LOWER VSBYS AND CIGS FOR KPDT/KYKM/KALW/KPSC AND
BRING GUSTY WINDS AT 20-25KTS OVER KRDM/KBDN WITH SUSTAINED WINDS
OF 12-15KTS THURSDAY AFTERNOON STARTING AROUND 20Z. FEASTER/97
PRELIMINARY POINT TEMPS/POPS
PDT 62 45 61 42 / 50 70 30 10
ALW 60 48 60 46 / 60 80 50 20
PSC 54 43 62 43 / 50 60 10 10
YKM 54 39 58 39 / 90 60 10 20
HRI 57 44 61 43 / 50 70 20 10
ELN 51 36 52 38 / 90 60 20 40
RDM 66 36 58 32 / 50 40 10 0
LGD 64 43 60 38 / 50 80 50 20
GCD 66 42 59 37 / 50 70 20 0
DLS 57 46 60 46 / 90 80 40 30
PDT WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...DENSE FOG ADVISORY UNTIL 10 AM PST THIS MORNING FOR WAZ029.
SHORT TERM...74
LONG TERM....74
AVIATION...97
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