690
FXUS66 KPDT 212221
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
221 PM PST WED JAN 21 2026
KEY POINTS
1. A HIGH PRESSURE RIDGE WILL DOMINATE AND DRY NORTHWEST FLOW WILL
PERSIST THROUGH THE SHORT TERM PERIOD
2. FOG AND STRATUS WILL BE THE MAIN CONCERN THROUGH THE PERIOD
DISCUSSION
CURRENT SATELLITE SHOWS A VERY PREDOMINANT STRATUS
DECK IN PLACE OVER THE CWA WITH ONLY THE EASTERN MOUNTAINS SEEING A
SLIGHT REPRIEVE FROM THE CLOUDS. THIS HAS AIDED IN KEEPING
TEMPERATURES COOL. HIGHS TODAY ACROSS MUCH OF THE REGION, WITH THE
EXCEPTION OF CENTRAL OR SOUTH AND SOUTHEAST OF BEND, WILL BE BELOW
35 DEGREES WHILE THE AFOREMENTIONED AREAS WILL BE IN THE LOW TO MID
40S.
MODELS ARE IN FORM AGREEMENT THAT THERE UPPER LEVEL HIGH PRESSURE
SYSTEM WILL REMAIN OVERHEAD THROUGH FRIDAY AHEAD OF A WEAK
SHORTWAVE. THAT SHORTWAVE IS EXPECTED TO MOVE OVER THE REGION
THURSDAY NIGHT INTO FRIDAY. HOWEVER, GUIDANCE SHOWS THIS TO BE
MOSTLY DRY WITH NO EXPECTED PRECIPITATION (80+% CONFIDENCE). ALSO,
700-500 MB GUIDANCE SHOWS VERY LITTLE INSTABILITY AND THE OMEGA
FIELD SHOWS LITTLE TO NO MIXING. WITH THAT, FOG AND LOW STRATUS WILL
LIKELY CONTINUE EVEN WITH THE DISTURBANCE COMING THROUGH FRIDAY.
AFTER FRIDAY, MODELS REMAIN IN RELATIVELY GOOD AGREEMENT THAT
ANOTHER HIGH PRESSURE RIDGE AND DRY NORTHWEST FLOW WILL SET UP OVER
THE REGION. THIS WILL CONTINUE TO KEEP THE STRATUS DECKS LOW AND
ALLOW FOR FOG TO REFORM. ESPECIALLY IN THE VALLEY AREAS WITH PATTERN
RECOGNITION ALLOWING CONFIDENCE IN THE FORECASTED DECKS AND FOG TO
BE RELATIVELY HIGH (60-80% CONFIDENCE). WITH THIS, TEMPERATURES WILL
REMAIN COOLER UNDER THE STRATUS DECK WITH TEMPERATURES AVERAGING IN
THE MID TO UPPER 30S WITH A FEW LOCATIONS SEEING LOW 40S BY THE END
OF THE WEEKEND.
BY THE BEGINNING OF THE WEEK, MODELS DIVERGE A BIT WITH THE ECMWF
KEEPING THE RIDGE OVER HEAD BUT WEAKENING, WHILE THE GFS BREAKS DOWN
THE RIDGE AND SHIFTS THE FLOW TO THE WEST. GUIDANCE SHOWS WINDS TO
REMAIN CALM THROUGH THE TRANSITIONS AS WELL. WITH THAT SAID,
CONFIDENCE IN HOW NEXT WEEK WILL SHAKE OUT IS LOW/MODERATE (40-60%
CONFIDENCE) IN WHICH WAY THE MODELS SWING. IF WE KEEP THE RIDGE
OVERHEAD, FOG AND STRATUS WILL REMAIN THE CONCERN. IF WE TURN
WESTERLY, WARMER TEMPERATURES COULD BE IN STORE IF THE SYSTEM CAN
SCOUR OUT THE COLD POOL. 90
AVIATION...00Z TAFS
NOT MUCH CHANGE EXPECTED ACROSS THE AREA WITH
CONTINUED LOW CLOUDS AND AREAS OF FOG. GENERALLY MVFR CONDITIONS
CURRENTLY, WITH IFR/LIFR IN A FEW AREAS. SOME DECREASE IN
CIGS/VSBYS IS POSSIBLE OVERNIGHT. WINDS ARE EXPECTED TO BE LIGHT.
PRELIMINARY POINT TEMPS/POPS
PDT 24 32 21 33 / 0 0 0 0
ALW 27 29 23 33 / 0 0 0 0
PSC 26 33 23 39 / 0 0 0 0
YKM 23 34 21 37 / 0 0 0 0
HRI 26 36 23 37 / 0 0 0 0
ELN 22 32 20 33 / 0 0 0 0
RDM 18 29 17 32 / 0 0 0 0
LGD 21 33 20 35 / 0 0 0 0
GCD 21 32 22 37 / 0 0 0 0
DLS 29 38 26 39 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
OR...FREEZING FOG ADVISORY UNTIL 10 AM PST THURSDAY FOR ORZ050.
WA...NONE.
SHORT TERM...90
LONG TERM....90
AVIATION...77
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