176
FXUS66 KPDT 101113
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
413 AM PDT SAT OCT 10 2026
KEY MESSAGES
- COLD AIR MASS EXPECTED TO MOVE THROUGH THE AREA THIS WEEKEND
AND NEXT WEEK
- BREEZY CONDITIONS THIS WEEKEND ALONG THE EASTERN OREGON
CASCADES, WASHINGTON CASCADES, LOWER COLUMBIA BASIN AND YAKIMA
VALLEY
- RETURN OF MOSTLY DRY CONDITIONS, LIGHT WINDS, AND ABOVE NORMAL
TEMPERATURES MIDDLE OF NEXT WEEK
DISCUSSION
SATURDAY THROUGH MONDAY: AN UPPER-LEVEL TROUGH
WITH A CLOSED LOW IS FORECAST TO TRACK SOUTHEASTWARD OVER THE
PACNW BRINGING A STREAM OF COLD, DRY AIR INTO THE REGION THIS
MORNING AND THROUGH THE WEEKEND (CONFIDENCE 99%). PER
PROBABILISTIC GUIDANCE OF THE GFS, GEPS, AND ECMWF ENSEMBLE
GUIDANCE, ANALYZING THE 700 AND 850 MB FRONTOGENESIS, A
PRONOUNCED COLD AIR ADVECTION IS FORECAST TO MOVE OVER THE AREA
THIS MORNING THROUGH THE WEEKEND INTO NEXT WEEK BRINGING NEAR
SUB-FREEZING TEMPERATURES FOR CENTRAL OREGON AND WALLOWA VALLEY
(CONFIDENCE 85%). CURRENTLY, FREEZE WARNINGS ARE IN EFFECT FOR
THOSE AREAS. COLDER AIR IS EXPECTED TO REMAIN OVER THE AREA
THROUGH THE WEEKEND INTO EARLY NEXT WEEK. BREEZY CONDITIONS ARE
FORECAST FOR SUNDAY AFTERNOON AS THIS SYSTEM AND COLD AIR
ADVECTION PROGRESSES THROUGH BRINGING GUSTS UP TO 25-40 MPH
ALONG THE CASCADES, LOWER COLUMBIA BASIN AND YAKIMA VALLEY
(CONFIDENCE 55%).
AS THIS SYSTEM PUSHES THROUGH THE AREA THIS WEEKEND AND REMAINS
RELATIVELY STAGNANT OVER OUR FORECAST AREA, MOST OF THE REGION WILL
SEE COOLER THAN NORMAL TEMPERATURES. DUE TO RELATIVELY LOW CLOUD
COVER AND LIGHT NORTH-NORTHWESTERLY WINDS, SUNDAY AND MONDAY MORNING
HAVE THE POTENTIAL TO SEE SUB-FREEZING TEMPERATURES IN THE LOW 20S.
LOWER ELEVATION AREAS IN THE AREA ARE FORECAST TO SEE TEMPERATURES
IN THE MID 20S AND MID 30S (CONFIDENCE 85%). AMES/01
TUESDAY THROUGH FRIDAY: MOSTLY DRY CONDITIONS AND ABOVE NORMAL
TEMPERATURES WILL REDEVELOP TUESDAY THROUGH THE REMAINDER OF THE
WORK WEEK (CONFIDENCE 55-85%). ENSEMBLE CLUSTER GUIDANCE FAVORS
UPPER LEVEL RIDGING BUILDING SLIDING INTO THE REGION AS THE
UPPER CLOSED OVER THE GREAT BASIN PUSHES EAST. TUESDAY INTO
WEDNESDAY, A WEAK SHORTWAVE WILL TRACK THROUGH BC AND CLIP THE
WA CASCADES WITH ISOLATED LIGHT SHOWERS (CONFIDENCE 60-70%).
THAT SAID, ABOUT 20% OF ENSEMBLE CLUSTER MEMBERS DEPICT A
STRONGER SHORTWAVE PASSAGE THAT WILL BRING ISOLATED SHOWERS TO
THE NORTHERN BLUE MOUNTAINS/FOOTHILLS AND WALLOWAS TUESDAY NIGHT
INTO WEDNESDAY.
THURSDAY AND FRIDAY, UPPER LEVEL RIDGING WILL SLOWLY MOVE EAST
ACROSS THE PACNW WHILE IT AMPLIFIES POLEWARD (CONFIDENCE 55-65%).
THIS WILL RESULT IN DRY CONDITIONS AND AFTERNOON TEMPERATURES
IN THE LOWER TO MID 70S ACROSS MUCH OF THE FORECAST AREA BY
FRIDAY AFTERNOON. BEHIND THE UPPER RIDGE, ENSEMBLE GUIDANCE
DOES DEPICT UPPER LEVEL TROUGHING DEVELOPING IN THE NORTHEAST
PACIFIC THAT WILL SLOWLY APPROACH THE REGION THEN SLOWLY MOVE
INLAND NEXT WEEKEND WITH THE NEXT POTENTIAL ROUND OF UNSETTLED
WEATHER (CONFIDENCE 40-55%). LAWHORN/82
AVIATION /12Z TAFS THROUGH 12Z SUNDAY/
VFR CONDITIONS ARE EXPECTED AT ALL TAF SITES THROUGH THIS TAF
PERIOD. DLS CAN EXPECT TO SEE GUSTS UP TO 23 KTS LATER IN THE
MORNING TO AFTERNOON HOURS, OTHERWISE WINDS WILL GENERALLY BE
LIGHT THROUGH THE PERIOD WITH WINDS 12 KTS OR LESS AT OTHER
SITES. VIS IS EXPECTED TO BE 6SM, WHILE CIGS ARE EXPECTED TO BE
3500 FT OR GREATER AT ALL SITES. 82/01
PRELIMINARY POINT TEMPS/POPS
PDT 58 32 56 33 / 0 0 10 0
ALW 58 36 57 36 / 0 0 10 0
PSC 63 35 62 35 / 0 0 0 0
YKM 61 38 60 34 / 0 20 0 0
HRI 61 34 60 34 / 0 0 10 0
ELN 55 31 56 29 / 20 30 0 0
RDM 54 23 50 22 / 0 0 10 0
LGD 54 30 51 30 / 0 0 10 10
GCD 54 27 51 28 / 0 0 0 10
DLS 62 39 64 37 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...FREEZE WARNING UNTIL 10 AM PDT THIS MORNING FOR ORZ050-511.
DISCUSSION...01/82
AVIATION...01/82
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