473
FXUS66 KPDT 271713
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1013 AM PDT SAT JUN 27 2026
KEY MESSAGES
- COOLER TODAY
- INCREASINGLY BREEZY TO WINDY OVERNIGHT PEAKING SUNDAY
AFTERNOON
DISCUSSION
A COMBINATION OF NIGHTTIME MICROPHYSICS RGB GOES SATELLITE AND
METAR DATA SHOWED POCKETS OF MOSTLY CLEAR CONDITIONS ACROSS THE
LOWER COLUMBIA BASIN, BUT SCATTERED TO BROKEN OVER MOST OF THE
BLUE MTN FOOTHILLS, CASCADES AND EASTERN MOUNTAINS OVERNIGHT, AS
THE BOUNDARY LAYER WAS UNDER A WESTERLY AND RELATIVE DRIER PUSH
OF AIR. AS WETTER GROUND, COLDER AIR ALOFT AND CLOUDS TO DAY
INFLUENCE THE THERMAL PROFILES, TEMPERATURES ARE ANTICIPATED TO
BE EVEN COOLER STRUGGLING INTO HE LOWER 70S EVEN ACROSS THE
TYPICALLY WARMER LOWER COLUMBIA BASIN BY THE LATE AFTERNOON.
THE PATTERN OF UPPER TROUGHING WILL CONTINUE TO INFLUENCE THE
CROSS CASCADES PRESSURE GRADIENT AS MODELS CONVERGE ON SUNDAY
AS A MUCH MORE WINDY DAY THROUGH THE GAPS AND LOWER COLUMBIA
BASIN/KITTITAS VALLEY, UNDERSCORED BY BREEZY TO WINDY CONDITIONS
OVERNIGHT SATURDAY INCREASING THOUGH SUNDAY AFTERNOON.
SLOWLY REBOUNDING TEMPERATURES WITH CONTINUED WESTERLY SURFACE
FLOW THROUGH MUCH OF NEXT WEEK BEFORE SOME ENSEMBLES/CLUSTER
DIFFERENCES OF POTENTIAL IMPACT BY FRIDAY THROUGH SUNDAY.
CLUSTER 4 THE MORE POTENTIALLY WET AND COOLER SOLUTION WITH A
CUTOFF UPPER LOW ALONG THE PAC NW COAST FOR THE JULY 4TH HOLIDAY
WEEKEND, IS ALSO SEEMINGLY MORE OF AN OUTLIER TO THE OTHER
CLUSTERS AS MEMBERS ACCOUNT FOR ONLY ABOUT 11% OF THE TOTAL.
EVEN ADDING IN CLUSTER 3 WHILE NOT A CLOSED LOW IS ALSO A COOLER
TROUGHING LOWER HEIGHT SOLUTION, THE COOLER WETTER PATTERNS
ACCOUNT FOR ABOUT 30%.
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
WESTERLY WINDS WILL BECOME INCREASINGLY BREEZY ACROSS THE REGION
THIS FORECAST PERIOD. MOST SITES ARE SEEING WINDS ABOVE 12 KTS
WITH GUSTS NEARING 20-30KTS EXCEPT BDN, WHICH WILL SEE WINDS
AFTER 19Z. DLS/YKM ARE BOTH ALSO EXPECTING SOME WIND SHEAR
WS019/28035KT FOR DLS AND WS020/31040KT FOR YKM. LASTLY, BDN/RDM
HAVE A 30% CHANCE OR LESS OF ISOLATED VICINITY THUNDERSTORMS
AFTER 21Z PERSISTING THROUGH 00Z.
FIRE WEATHER
ISOLATED DRY THUNDERSTORMS WITH LIGHTNING RISK IS POSSIBLE THIS
AFTERNOON IN THE CASCADE CREST AND JOHN DAY HIGHLANDS (10-20 %
CONFIDENCE). OTHER THAN THAT, LIMITED FIRE WEATHER IS EXPECTED
RISK OVER THE WEEKEND AS COOLER WEATHER TAKES HOLD, LIMITING THE
LOWER BOUNDS FOR AFTERNOON RELATIVE HUMIDITY. WESTERLY WINDS
WILL BE GETTING STRONGER THROUGH THE OVERNIGHT AND INTO SUNDAY
AFTERNOON AS RELATIVE HUMIDITY SUNDAY AFTERNOON REMAINS AROUND
40% OR HIGHER ACROSS CENTRAL OREGON AND INTO THE COLUMBIA BASIN.
ISOLATED DRY THUNDERSTORM WITH LIGHTNING RISK IS POSSIBLE THIS
AFTERNOON IN THE CASCADE CREST AND JOHN DAY HIGHLANDS (10-20 %
CONFIDENCE).
PRELIMINARY POINT TEMPS/POPS
PDT 69 46 73 47 / 0 10 10 10
ALW 71 52 74 52 / 10 10 10 10
PSC 76 50 81 50 / 0 0 0 0
YKM 74 49 81 51 / 0 10 10 0
HRI 73 48 77 48 / 0 0 0 0
ELN 67 46 71 48 / 0 10 10 0
RDM 62 36 67 35 / 20 20 0 0
LGD 63 44 66 45 / 20 30 20 10
GCD 62 39 66 40 / 70 50 20 10
DLS 70 52 73 52 / 20 10 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...NONE.
DISCUSSION...86
AVIATION...90
FIRE WEATHER...99
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