750
FXUS66 KPDT 291119
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
419 AM PDT SAT AUG 29 2026
KEY MESSAGES
- HIGH CONFIDENCE (99%) THAT A LOW-PRESSURE SYSTEM WILL TRACK
OVER THE PACIFIC NORTHWEST TODAY INTO EARLY SUNDAY, RESULTING
IN BELOW-NORMAL TEMPERATURES AND WIDESPREAD BREEZY WESTERLY
WINDS.
- ELEVATED FIRE WEATHER CONDITIONS TODAY DUE TO BREEZY WINDS,
BUT LOW CONFIDENCE (<40%) IN WIDESPREAD RED FLAG CONDITIONS.
- VERY LOW TO SLIGHT CHANCE (5-15%) OF THUNDERSTORMS TODAY FOR
THE WASHINGTON CASCADES AND NORTHEAST BLUE MOUNTAINS.
- LOW-MEDIUM PROBABILITY (20-50%) OF NEAR-FREEZING MORNING LOW
TEMPERATURES IN POPULATED, COLD-PRONE VALLEYS OF CENTRAL AND
NORTHEAST OREGON ON SUNDAY, EXCEPT MEDIUM-HIGH PROBABILITY
(50-75%) IN WALLOWA VALLEY.
DISCUSSION
SATELLITE IMAGERY EARLY THIS MORNING SHOWS A CLOSED UPPER-LEVEL
LOW OVER NORTHWEST WASHINGTON AND SOUTHWEST BRITISH COLUMBIA.
CONFIDENCE IS VERY HIGH (99%) THAT THE LOW WILL TRACK INLAND
OVER THE PACIFIC NORTHWEST TODAY, THEN EXIT TO THE EAST THROUGH
SUNDAY. WIDESPREAD BREEZY WESTERLY WINDS ARE FORECAST TODAY,
STRONGEST THOUGH THE CASCADE GAPS. NBM PROBABILITIES SUGGEST
GENERALLY MEDIUM (30-70%) CHANCES (LOCALLY HIGHER) OF REACHING
ADVISORY-LEVEL WIND GUSTS THROUGH OUR MOST WIND-PRONE AREAS
SUCH AS THE KITTITAS VALLEY AND THE EASTERN COLUMBIA RIVER GORGE
AND VICINITY. DESPITE THE BREEZY WINDS, CHANCES OF WIDESPREAD
RED FLAG CONDITIONS ARE LOW (<40%) DUE TO BELOW-NORMAL
TEMPERATURES AND SEASONABLY LOW RELATIVE HUMIDITY.
RAIN SHOWERS ARE VERY LIKELY (UP TO 95% POPS) ALONG THE
WASHINGTON CASCADE CREST THIS MORNING INTO EARLY AFTERNOON AS
THE LOW SWINGS INLAND. CHANCES OF SHOWERS AND THUNDERSTORMS ARE
LOWER (5-15%) OVER THE BLUE MOUNTAINS THIS AFTERNOON, BUT STILL
WORTH A BRIEF MENTION.
LOOKING AHEAD, THERE ARE LOW-MEDIUM CHANCES (20-50%) OF NEAR-
FREEZING MORNING TEMPERATURES (LOWER TO MIDDLE 30S) IN
POPULATED, COLD-PRONE VALLEYS OF CENTRAL AND NORTHEAST OREGON
SUNDAY AND MONDAY IN THE WAKE OF THE COLD UPPER LOW, EXCEPT FOR
50-75% SUNDAY MORNING FOR WALLOWA VALLEY. NBM PROBABILITIES ARE
LIKELY TOO AGGRESSIVE SUNDAY MORNING DUE TO SOME LINGERING
BREEZINESS INTO THE EARLY OVERNIGHT HOURS, THOUGH FORECAST PWATS
(GENERALLY 0.4" OR LESS) AND TEMPERATURES ALOFT ARE SUPPORTIVE
OF CHILLY CONDITIONS. THINKING THE COLDEST TEMPERATURES IN SOME
VALLEYS WILL FALL ON MONDAY MORNING WITH LIGHT WINDS AREAWIDE
UNDER A SHORTWAVE RIDGE, SOMETHING NBM PROBABILITIES DO NOT
HIGHLIGHT WELL. DID ISSUE A FREEZE WATCH FOR WALLOWA VALLEY,
VALID LATER TONIGHT INTO SUNDAY MORNING.
ANALYSIS OF ENSEMBLE CLUSTERS SUGGESTS A CONTINUED TROUGHING
PATTERN FOR THE PACIFIC NORTHWEST BY THE MIDDLE OF NEXT WEEK
WITH ALL FOUR CLUSTERS EXHIBITING SOME FLAVOR OF TROUGH/UPPER
CLOSED LOW AND NEAR-NORMAL OR BELOW-NORMAL 500-HPA HEIGHTS.
WILL THE REGION SEE ITS FIRST WIDESPREAD WETTING RAIN WITH THE
FALL-LIKE PATTERN? NBM PROBABILITIES ARE QUITE OPTIMISTIC FOR
THE 48-HR PERIOD ENDING 5AM FRIDAY. IN GENERAL, IT SHOWS 40-70%
CHANCES OF 0.10" OF PRECIPITATION FOR NON-MOUNTAIN AREAS WITH
50-90% CHANCES ACROSS THE MOUNTAINS (HIGHEST CHANCES FOR THE
CASCADES).
AVIATION /12Z TAFS THROUGH 12Z SUNDAY/
VFR CONDITIONS ARE FORECAST THROUGH THE PERIOD, ALBEIT WITH
BREEZY WESTERLY WINDS AS A LOW-PRESSURE SYSTEM MOVES OVER THE
PACIFIC NORTHWEST TODAY. THERE IS VERY LOW CONFIDENCE (<20%) IN
SMOKE FROM AREA WILDFIRES AFFECTING VSBYS/CIGS AT ANY TERMINAL,
AND LOW CONFIDENCE (10-30%) IN LOW STRATUS PRODUCING MVFR CIGS
THIS MORNING (BDN/RDM) OR SUNDAY MORNING (PDT/ALW/DLS). SHOWERS
WILL BE MOSTLY CONFINED TO THE MOUNTAINS, BUT THERE IS A VERY
LOW (5%) CHANCE OF AFTERNOON SHOWERS AT YKM/PSC/PDT/ALW.
PRELIMINARY POINT TEMPS/POPS
PDT 73 42 76 46 / 0 0 0 0
ALW 74 48 76 51 / 0 0 0 0
PSC 78 45 78 46 / 0 0 0 0
YKM 75 47 79 50 / 0 0 0 0
HRI 75 46 78 46 / 0 0 0 0
ELN 68 43 74 45 / 10 0 0 0
RDM 72 33 78 38 / 0 0 0 0
LGD 74 39 78 42 / 0 0 0 0
GCD 76 40 79 44 / 0 0 0 0
DLS 74 51 79 53 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...AIR QUALITY ALERT UNTIL NOON PDT MONDAY FOR ORZ041-505-506-
509>511.
FREEZE WATCH FROM LATE TONIGHT THROUGH SUNDAY MORNING FOR
ORZ050.
DISCUSSION...86
AVIATION...86
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