634
FXUS66 KPDT 031703
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1003 AM PDT WED JUN 3 2026
KEY MESSAGES
- LIGHT SHOWERS AND AFTERNOON ISOLATED STORMS POSSIBLE TODAY.
- BREEZY AFTERNOON WINDS TODAY AND THROUGH WEEK, PEAKING FRIDAY.
*WIND ADVISORIES ISSUED*
- COOLING TREND THROUGH SATURDAY, WARMING EARLY NEXT WEEK.
DISCUSSION
CURRENT RADAR AND INFRARED SATELLITE IMAGERY SHOWING POCKETS OF
LIGHT RETURNS ACROSS CENTRAL OREGON AS MID-TO HIGH LEVEL CLOUDS
SLOWLY MOVE ACROSS THE COLUMBIA BASIN. THIS IS IN RESPONSE TO
AN APPROACHING UPPER LEVEL SHORTWAVE THAT HAS TAPPED INTO SOME
MID-LATITUDE MOISTURE TO ALLOW FOR LIGHT SHOWERS TO EXTEND EAST
OF THE CASCADES THROUGHOUT THE DAY. THE BEST CHANCES (30-50%)
FOR SHOWERS WILL BE ALONG THE EAST SLOPES OF THE CASCADES AND
CENTRAL OREGON THROUGH THIS AFTERNOON, AND THROUGH GRANT, UNION,
AND WALLOWA COUNTIES THIS AFTERNOON THROUGH THE EVENING. THESE
COUNTIES WILL ALSO EXPERIENCE THE POTENTIAL FOR ISOLATED
THUNDERSTORMS AS THE INCOMING SHORTWAVE ERODES THE BACKSIDE OF
THE EXITING TRANSIENT RIDGE. THE HREF ADVERTISES SURFACE CAPE
VALUES OF 150-350 J/KG WITH 0-6KM SHEAR OF 30-35KTS, WHICH IS
SUPPORTIVE OF CONVECTIVE ACTIVITY AS ALSO INDICATED BY THE STORM
PREDICTION CENTER INCLUDING THE AREA IN THEIR GENERAL
THUNDERSTORMS (0 OF 5) CATEGORY. HOWEVER, 700-500MB LAPSE RATES
DO STILL LOOK MARGINAL (6-6.5C/KM) AND DECREASE THROUGH THE
AFTERNOON AND EVENING. THUS, IT IS EXPECTED THAT ISOLATED, SUB-
SEVERE THUNDERSTORM CELLS WILL DEVELOP OVER OUR CENTRAL AND
NORTHEASTERN OREGON ZONES THIS AFTERNOON AND EVENING.
THE INCOMING SHORTWAVE WILL ALSO LEAD TO THE TIGHTENING OF A
PRESSURE GRADIENT ALONG THE CASCADES, DUE TO THE INTERACTION
WITH THE EXITING TRANSIENT RIDGE THAT BROUGHT WARM AND SUNNY
CONDITIONS TO THE AREA ON TUESDAY. THIS ENHANCED GRADIENT WILL
IMPACT MUCH OF THE REGION WITH INCREASED WINDS AS THE COLD FRONT
PASSES MID-AFTERNOON WITH GUSTS OF 25-35 MPH POSSIBLE ACROSS
THE BLUE MOUNTAIN FOOTHILLS AND THE COLUMBIA BASIN. THE HIGHEST
WINDS WILL BE EXPERIENCED ACROSS THE SIMCOE HIGHLANDS AND
KITTITAS VALLEY AS WEST-NORTHWEST SUSTAINED WINDS OF AROUND 30
MPH AND GUSTS UP TO 50 MPH WILL BE POSSIBLE. AS A RESULT, WIND
ADVISORIES HAVE BEEN ISSUED FROM 1 PM TODAY THROUGH MIDNIGHT
TONIGHT. THE NBM HIGHLIGHTS A 70-80% CHANCE OF 45 MPH GUSTS OR
GREATER THROUGH THE SIMCOE HIGHLANDS. IN ADDITION, THE NAM AND
SREF INDICATE A 5-6MB PRESSURE GRADIENT BETWEEN PAE AND PSC,
HINTING TO ADVISORY-LEVEL WINDS THROUGH THE KITTITAS VALLEY.
TODAY'S SHORTWAVE IS SPINNING OFF A STRONGER UPPER LEVEL LOW
PRESSURE SYSTEM CURRENTLY LOCATED IN THE GULF OF ALASKA. THIS
LOW PRESSURE WILL SLOWLY MOVE SOUTH ALONG THE COAST OF BRITISH
COLUMBIA THURSDAY AND EARLY FRIDAY BEFORE MOVING ONSHORE FRIDAY
EVENING AND PASSING THROUGH THE AREA ON SATURDAY. MOISTURE LOOKS
TO BE LACKING WITH THIS EVENT AND STAYS CONFINED AT ELEVATION
ACROSS THE CASCADES. HOWEVER, A BUILDING UPPER LEVEL RIDGE TO
OUR EAST AND ASSOCIATED SURFACE HIGH PRESSURE WILL LEAD TO
WINDY CONDITIONS ACROSS MUCH OF THE AREA. THE GFS AND NAM
SUGGEST A PRESSURE GRADIENT OF 8-10MB BETWEEN PQR AND OTX, WHICH
WOULD RELATED TO ADVISORY-LEVEL WINDS ACROSS THE SIMCOE
HIGHLANDS AND NORTH-CENTRAL OREGON. THE NBM SHOWS A 70-80%
CHANCE OF THIS OCCURRING FRIDAY AFTERNOON AND EVENING. BREEZY
WINDS ARE ALSO EXPECTED ACROSS THE COLUMBIA BASIN, BLUE MOUNTAIN
FOOTHILLS, AND YAKIMA/KITTITAS VALLEY, BUT SUB-ADVISORY WINDS
ARE CURRENTLY EXPECTED. CONSISTENCY IN GUIDANCE IS IMPROVING AS
59% OF LREF ENSEMBLE MEMBERS SUGGEST WINDS NEAR OR SLIGHTLY
ABOVE THE CURRENT FORECAST, WITH 41% OF MEMBERS HINTING AT AN
EARLIER OR WEAKER INCOMING SYSTEM. ANOTHER RESULT OF THE
DROPPING SYSTEM WILL BE COOLING TEMPERATURES, AS HIGHS DROP FROM
THE UPPER 70S TO LOW 80S TODAY INTO THE UPPER 60S TO LOW 70S
SATURDAY ACROSS THE LOWER COLUMBIA BASIN, BLUE MOUNTAIN
FOOTHILLS, AND PORTIONS OF CENTRAL OREGON. THESE SATURDAY VALUES
ARE 8 TO 10 DEGREES BELOW NORMAL FOR THIS TIME OF YEAR. 75
AVIATION /18Z TAFS THROUGH 18Z THURSDAY/
VFR CONDITIONS CONTINUE TO PREVAIL THROUGH THE TAF PERIOD.
SLIGHT CHANCE OF SHOWERS IN ALW/PSC, BUT NOTHING IMPACTFUL TO
BRING MVFR OR LOWER VALUES. WINDS WILL BE BREEZIER OVERALL BY
THE AFTERNOON TO LATE AFTERNOON HOURS, GUSTING UP TO 15 TO 25
KNOTS.
FIRE WEATHER
ELEVATED FIRE WEATHER CONCERNS ARE ANTICIPATED ON FRIDAY ACROSS
THE COLUMBIA BASIN (FIRE WEATHER ZONE WA691) DUE TO A
COMBINATION OF BREEZY TO WINDY CONDITIONS AND AFTERNOON RELATIVE
HUMIDITY (RH) DROPPING TO 20-25%. COMPOUNDING THIS THREAT IS A
DRY BASELINE; THURSDAY AFTERNOON'S LOW RH (15-25%) WILL BE
FOLLOWED BY ONLY MODERATE TO GOOD (50-65%) OVERNIGHT HUMIDITY
RECOVERIES HEADING INTO FRIDAY MORNING. FUELS IN ZONE WA691 HAVE
BEEN DECLARED READY AND RECEPTIVE. WHILE THESE COMPOUNDING
FACTORS SUGGEST A RED FLAG WARNING MAY BE WARRANTED FOR FRIDAY,
NO OFFICIAL PRODUCTS HAVE BEEN ISSUED AT THIS TIME. 75
PRELIMINARY POINT TEMPS/POPS
PDT 78 47 75 47 / 10 10 0 0
ALW 79 53 76 52 / 10 10 0 0
PSC 83 52 80 49 / 20 10 0 0
YKM 80 48 80 47 / 40 0 0 0
HRI 81 50 78 50 / 10 0 0 0
ELN 73 45 72 44 / 50 0 0 0
RDM 74 37 76 40 / 10 0 0 0
LGD 76 44 74 43 / 40 20 0 0
GCD 78 42 77 42 / 40 10 0 0
DLS 78 53 77 52 / 10 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...WIND ADVISORY UNTIL MIDNIGHT PDT TONIGHT FOR WAZ026-521.
OR...NONE.
DISCUSSION...75
AVIATION...95
FIRE WEATHER...99
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