529
FXUS66 KPDT 050537
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1037 PM PDT SUN OCT 4 2026
KEY MESSAGES
- UPPER LEVEL HIGH PRESSURE OVER THE REGION WILL CONTINUE TO
BRING DRY CONDITIONS AND ABOVE NORMAL TEMPERATURES THROUGH
THURSDAY
- LOCALLY BREEZY WINDS THROUGH THE CASCADE GAPS MONDAY AFTERNOON
- GROWING POTENTIAL FOR MOUNTAIN SHOWERS FRIDAY INTO NEXT
WEEKEND
DISCUSSION
MUCH LIKE YESTERDAY, LITTLE TO TALK ABOUT ON VISIBLE SATELLITE
THIS AFTERNOON AS HIGH PRESSURE ALOFT IS PRODUCING CLEAR SKIES
OVER MUCH OF THE PACNW.
UPPER LEVEL RIDGING CONTINUES TO SIT OVER THE PACNW TODAY, WITH
RIDGING EXPECTED TO REMAIN OVERHEAD THROUGH AT LEAST THURSDAY
(CONFIDENCE 85-90%). TOMORROW THE RIDGE AXIS WILL PUSH EAST OF
THE PACNW AS AN UPPER TROUGH SLIDES INTO NORTHERN BC, WITH ZONAL
FLOW DEVELOPING OVERHEAD AND HIGH PRESSURE ALOFT TO THE SOUTH
(CONFIDENCE 80-85%). TUESDAY THROUGH THURSDAY, ENSEMBLE GUIDANCE
CONTINUES TO BE IN GREAT AGREEMENT OF UPPER LEVEL RIDGING
BUILDING BACK OVER THE PACNW THEN AMPLIFYING POLEWARD. BY
FRIDAY, ENSEMBLE GUIDANCE IS IN GOOD AGREEMENT THAT THE UPPER
LEVEL RIDGE WILL BE PUSHED OUT OF THE REGION BY AN UPPER LEVEL
TROUGH. HOWEVER THERE IS DISAGREEMENT BETWEEN THE ECMWF AND GFS
ENSEMBLE MEMBERS IN TIMING, POSITION, AND STRENGTH OF THE
INCOMING UPPER TROUGH THROUGH SATURDAY.
TEMPERATURES WILL CONTINUE ON A GRADUAL INCREASE TODAY, WITH
AFTERNOON TEMPERATURES PEAKING IN THE UPPER 70S TO MID 80S
TOMORROW (CONFIDENCE 80-90%). TEMPERATURES WILL DROP A COUPLE
DEGREES INTO TUESDAY, BUT EXPECT HIGH TEMPERATURES TO REMAIN IN
THE UPPER 70S TO LOW 80S. CONDITIONS ARE EXPECTED TO REMAIN DRY
THROUGH THURSDAY WITH LIGHT, DIURNALLY DRIVEN WINDS EACH DAY.
THE EXCEPTION WILL BE TOMORROW AFTERNOON, WHERE BREEZY WINDS
(15-20 MPH WITH GUSTS TO AROUND 30 MPH) WILL DEVELOP THROUGH THE
CASCADE GAPS AS SURFACE PRESSURE GRADIENTS SLIGHTLY STRENGTHEN
IN RESPONSE TO THE UPPER TROUGH PASSAGE TO THE NORTH. AS
MENTIONED EARLIER, UNCERTAINTY IN THE TIMING/STRENGTH OF A
TROUGH PASSAGE FRIDAY AND SATURDAY INVITES LOW CONFIDENCE
(15-20%) IN EXTENT, INTENSITY, AND TIMING OF SHOWERS DURING THIS
PERIOD. HOWEVER, THERE IS MODERATE CONFIDENCE (50-60%) THAT
THE CASCADE CREST/EAST SLOPES WILL SEE SHOWERS SOMETIME DURING
THIS PERIOD WITH LOWER CONFIDENCE (25-35%) IN THE NORTHERN BLUES
SEEING ANY PRECIPITATION AS WELL. OTHERWISE, THE INCOMING UPPER
TROUGH WILL ALSO PRODUCE BREEZY WEST WINDS THROUGH THE CASCADE
GAPS AND LOWER ELEVATIONS (CONFIDENCE 55-60%), BUT LOW
CONFIDENCE (25-30%) IN FORECAST TIMING/STRENGTH OF WINDS FOR
FRIDAY AND SATURDAY. LAWHORN/82
AVIATION /06Z TAFS THROUGH 06Z TUESDAY/
VFR CONDITIONS ARE FORECAST THROUGH THE PERIOD (99% CONFIDENCE).
WINDS WILL BE PREDOMINANTLY LIGHT, DIURNALLY AND TERRAIN-DRIVEN,
EXCEPT FOR BREEZY WESTERLY WINDS AT DLS LATE MONDAY AFTERNOON
AND EVENING. SKIES WILL RANGE FROM CLEAR TO MOSTLY CLOUDY AS A
WEAK WEATHER SYSTEM MOVES INTO THE REGION.
PRELIMINARY POINT TEMPS/POPS
PDT 46 82 47 80 / 0 0 0 0
ALW 53 83 54 80 / 0 0 0 0
PSC 49 83 48 80 / 0 0 0 0
YKM 50 83 50 80 / 0 0 0 0
HRI 47 84 49 81 / 0 0 0 0
ELN 45 78 47 77 / 0 0 0 0
RDM 48 86 43 84 / 0 0 0 0
LGD 44 86 47 83 / 0 0 0 0
GCD 50 88 48 86 / 0 0 0 0
DLS 52 86 51 84 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...NONE.
DISCUSSION...82
AVIATION...86
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