254
FXUS66 KPDT 271725
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1025 AM PDT FRI MAR 27 2026
KEY MESSAGES
- WARM, DRY CONDITIONS ACROSS THE AREA THROUGH SUNDAY AFTERNOON
- A RETURN OF ACTIVE WEATHER SUNDAY NIGHT INTO MONDAY WITH LIGHT
PRECIPITATION IN THE MOUNTAINS
- POTENTIAL FOR MORE WIDESPREAD PRECIPITATION CHANCES, BREEZY
WINDS, AND COOLER CONDITIONS WITH UPPER TROUGH PASSAGE TUESDAY
NIGHT THROUGH THURSDAY
DISCUSSION
TODAY THROUGH SUNDAY AFTERNOON: A BROAD UPPER
LEVEL RIDGE TO THE SOUTH WILL PLACE THE PACNW UNDER A WEST
SOUTHWEST FLOW ALOFT INTO SUNDAY. WARMING UNDER THE UPPER RIDGE
PATTERN WILL RESULT IN AFTERNOON HIGH TEMPERATURES IN THE 60S
ACROSS THE LOWER ELEVATIONS, WITH A LOCALIZED LOW 70S ACROSS
THE JOHN DAY BASIN AND CENTRAL OR. SKIES WILL REMAIN MOSTLY
CLEAR THROUGH TODAY, HOWEVER, INCREASING CIRRUS WILL BRING
PARTLY CLOUDY TO CLOUDY SKIES BY SATURDAY, WITH INCREASING MID
LEVEL CLOUD COVER AHEAD OF A TROUGH PASSAGE SUNDAY.
SUNDAY AFTERNOON THROUGH MONDAY NIGHT: PRECIPITATION CHANCES
ACROSS THE MOUNTAINS WILL INCREASE AHEAD OF AN UPPER TROUGH
DROPPING OUT OF THE GULF OF ALASKA BY SUNDAY AFTERNOON. SNOW
LEVELS WILL DROP SUNDAY NIGHT THROUGH MONDAY AS THE UPPER TROUGH
AND AN ATTENDANT SURFACE COLD FRONT SWING SOUTHEAST ACROSS THE
REGION, RESULTING IN LIGHT SNOW ACCUMULATIONS ACROSS THE
CASCADES AND NORTHERN BLUES THROUGH MONDAY NIGHT. TOTAL
ACCUMULATIONS REMAIN BELOW ADVISORY LEVEL, WITH ONLY A 30-45%
CHANCE OF 2 INCHES OF SNOW AT PASS LEVEL IN THE OR CASCADES AND
NORTHERN BLUES; CHANCES OF 2 INCHES OF SNOW ACROSS THE WA
CASCADE PASSES WILL BE 45-80%. BREEZY WESTERLY WINDS (GUSTS
20-35 MPH) WILL ALSO DEVELOP ACROSS THE LOWER ELEVATIONS SUNDAY
AND MONDAY WITH APPROACH AND SUBSEQUENT PASSAGE OF THE
TROUGH/FRONT SYSTEM.
TUESDAY THROUGH THURSDAY: POST THE TROUGH EXIT MONDAY NIGHT,
ENSEMBLE CLUSTER GUIDANCE IS IN DECENT AGREEMENT OF A SPLIT FLOW
(RIDGE TO THE NORTH, TROUGH TO THE SOUTH) MOVING ACROSS THE
PACNW TUESDAY. HOWEVER, THERE IS SPLIT AGREEMENT ON THE SETUP OF
THIS SPLIT FLOW, WITH 55% OF MEMBERS (ECMWF, GFS, CANADIAN)
FAVORING A BREAK IN PRECIPITATION ACROSS THE AREA, WHILE THE
REMAINING 45% OF MEMBERS KEEP LIGHT PRECIPITATION CHANCES
MAINLY ACROSS OR THROUGH TUESDAY.
WEDNESDAY, ENSEMBLE CLUSTER MEMBERS COME BACK INTO GOOD
AGREEMENT OF AN UPPER LOW DROPPING OUT OF THE GULF OF ALASKA,
THEN TRANSITIONING INTO AN UPPER TROUGH AS IT CROSSES THE PACNW
THURSDAY. THIS WILL BRING A RETURN TO WIDESPREAD LIGHT RAIN
CHANCES IN THE LOWER ELEVATIONS, WITH A RAIN/SNOW MIX IN AREAS
ABOVE 2.5KFT, AND LIGHT TO MODERATE SNOW ACCUMULATIONS ACROSS
THE MOUNTAINS. NBM 48 HOUR GUIDANCE SUGGESTS A 60-85% CHANCE OF
4 INCHES OF SNOW ACROSS CASCADE PASSES AND THE NORTHERN BLUES
ENDING THURSDAY AFTERNOON. OTHERWISE, THE INCOMING UPPER LOW
WILL ALSO BRING A RETURN OF BREEZY CONDITIONS (GUSTS 25-40MPH)
ACROSS THE FORECAST AREA WEDNESDAY AND THURSDAY (CONFIDENCE
55-65%). LAWHORN/82
AVIATION /18Z TAFS THROUGH 18Z SATURDAY/
VFR CONDITIONS PREVAIL FOR ALL SITES WITH DRY CONDITIONS
PREVAILING THROUGH THE FORECAST PERIOD. LIGHT AND VARIABLE WINDS
LESS THAN 12 KNOTS SUSTAINED. NO SUB-VFR CONDITIONS EXPECTED.
PRELIMINARY POINT TEMPS/POPS
PDT 60 35 64 40 / 0 0 0 0
ALW 60 39 63 42 / 0 0 0 0
PSC 62 37 67 41 / 0 0 0 0
YKM 59 37 64 36 / 0 0 0 0
HRI 62 36 67 41 / 0 0 0 0
ELN 55 34 56 34 / 0 0 0 0
RDM 68 31 66 35 / 0 0 0 0
LGD 62 35 65 37 / 0 0 0 0
GCD 67 35 66 38 / 0 0 0 0
DLS 62 40 64 40 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...NONE.
DISCUSSION...82
AVIATION...95
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