690
FXUS66 KPDT 111037
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
237 AM PST TUE NOV 11 2025
DISCUSSION
SATELLITE IMAGERY REVEALS ZONAL FLOW ALOFT OVER THE
FORECAST AREA, WITH CIRRUS BLANKETING THE MAJORITY OF SOUTH-
CENTRAL TO SOUTHEAST WASHINGTON AND NORTH-CENTRAL TO NORTHEAST
OREGON. BENEATH THE CIRRUS, SOME LOWER CLOUDS ARE PRESENT, BUT
HIDDEN FROM VIEW. AT THE SURFACE COLD POOLING IS EVIDENT,
EXTENDING FROM THE THE LOWER COLUMBIA BASIN OF OREGON NORTH
THROUGH THE LOWER ELEVATIONS OF SOUTH-CENTRAL WASHINGTON. FOG,
LOCALLY DENSE WITH VISIBILITY OF ONE-QUARTER MILE OR LESS, HAS
FORMED IN THE COOL, MOIST AIR MASS. HAVE ISSUED A SPECIAL WEATHER
STATEMENT FOR THE PATCHY DENSE FOG, WHICH IS EXPECTED TO PERSIST
IN PORTIONS OF THE LOWER COLUMBIA BASIN OF WASHINGTON AND YAKIMA
VALLEY THROUGH EARLY TO MID-MORNING. FARTHER SOUTH, A MILDER, LESS
SATURATED AIR MASS REMAINS IN PLACE ACROSS THE BLUE MOUNTAIN
FOOTHILLS AND MUCH OF THE REMAINDER OF CENTRAL TO EASTERN OREGON.
ENSEMBLE NWP GUIDANCE IS IN EXCELLENT AGREEMENT THAT A COUPLE
VORT LOBES IN THE VICINITY OF THE GULF OF ALASKA WILL DIVE
SOUTHEAST TODAY THROUGH WEDNESDAY AND CARVE OUT A DEEP 500-HPA
TROUGH/CLOSED LOW OFFSHORE. MEANWHILE, A 500-HPA RIDGE WILL BUILD
OVER THE ROCKIES AND INTO THE PACIFIC NORTHWEST, TURNING FLOW
ALOFT SOUTHWESTERLY. CURRENTLY, NOT ANTICIPATING ANY NOTEWORTHY
WEATHER UNTIL WEDNESDAY NIGHT AND THURSDAY MORNING WHEN THE
AFOREMENTIONED CLOSED LOW APPROACHES THE OR COAST. WHILE THERE IS
SIGNIFICANTLY BETTER AGREEMENT IN PATTERN DETAILS RELATIVE TO
YESTERDAY'S MODEL RUNS, ENSEMBLE MEMBERS ARE STILL DISPLAYING A
NOTABLE RANGE OF SOLUTIONS WITH REGARD TO THE FORMATION AND
EVOLUTION OF A SURFACE LOW AND COLD FRONT. THE PATTERN GENERALLY
FAVORS BREEZY TO WINDY SOUTHEASTERLY TO SOUTHERLY WINDS ACROSS
CENTRAL OREGON, THE BLUE MOUNTAINS AND THEIR FOOTHILLS, AND THE
GRANDE RONDE VALLEY. CURRENTLY, HAVE LOW-MEDIUM (20-50 PERCENT)
CONFIDENCE IN ADVISORY-LEVEL WINDS WEDNESDAY NIGHT AND THURSDAY
FOR THE AFOREMENTIONED ZONES.
LOOKING AHEAD, ENSEMBLE CLUSTERS ALL INDICATE THE MAIN 500-HPA
CLOSED LOW WILL DIVE SOUTH INTO CALIFORNIA AND THE SOUTHWEST WHILE
A WEAKER SHORTWAVE TROUGH WILL SLIDE ACROSS THE PACIFIC NORTHWEST
LATE THURSDAY THROUGH FRIDAY. NORTHWESTERLY TO WESTERLY FLOW
ALOFT IS THEN FAVORED THROUGH SATURDAY AS THE SHORTWAVE EXITS AND
A BRIEF RIDGE MOVES OVERHEAD. BY SUNDAY, ALL ENSEMBLE CLUSTERS
SHOW SOME FLAVOR OF A SHORTWAVE TROUGH APPROACHING THE WEST COAST.
AVIATION...06Z TAFS...PREVIOUS DISCUSSION
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
PRELIMINARY POINT TEMPS/POPS
PDT 57 39 56 41 / 0 10 0 20
ALW 57 43 55 45 / 0 10 10 20
PSC 53 38 53 39 / 0 10 0 10
YKM 55 39 54 39 / 0 20 10 40
HRI 55 40 53 41 / 0 10 0 20
ELN 51 36 50 37 / 0 30 20 50
RDM 62 41 64 43 / 0 0 0 30
LGD 63 45 62 46 / 0 0 0 10
GCD 67 44 66 47 / 0 0 0 30
DLS 58 44 57 45 / 10 20 20 60
PDT WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
DISCUSSION...86
AVIATION...97
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