938
FXUS66 KPDT 090547
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1047 PM PDT MON JUN 8 2026
KEY MESSAGES
- WIDESPREAD RAIN SHOWER CHANCES AND ISOLATED THUNDERSTORMS
ACROSS THE FORECAST AREA TODAY INTO TUESDAY
- BREEZY LOWER ELEVATIONS WINDS DEVELOP TONIGHT THROUGH
WEDNESDAY
- DRYING AND WARMING TREND LATE WEEK THROUGH THE WEEKEND
DISCUSSION
TODAY THROUGH WEDNESDAY: SATELLITE IMAGERY THIS
AFTERNOON SHOWS A SHORTWAVE TROUGH WITH AN ATTENDANT SURFACE LOW
JUST OFFSHORE THE PACNW, WITH CLOUDY CONDITIONS ACROSS MUCH OF
THE REGION. AREA RADAR SHOWS THE WESTERN HALF OF WA/OR COVERED
IN SHOWERS, WITH SHOWER ACTIVITY EXTENDING TO THE EAST SLOPES OF
THE CASCADES, EASTERN COLUMBIA RIVER GORGE, AND CENTRAL OR.
A SHORTWAVE TROUGH AND SURFACE LOW WILL CONTINUE TO SWING
ACROSS THE PACNW TODAY THROUGH TONIGHT. A RAIN SHIELD WILL
SPREAD NORTH AND EAST FROM THE CASCADE CREST THROUGH THE
REMAINDER OF THIS AFTERNOON AND EVENING, WITH ISOLATED TO
SCATTERED SHOWERS DEVELOPING OVERNIGHT. CAMS CONTINUE TO
INDICATE WEAK SURFACE BASED INSTABILITY DEVELOPING ACROSS THE
EASTERN OR MOUNTAINS THIS AFTERNOON WILL ALSO RESULT IN LOW
CHANCES (5-15%) OF ISOLATED THUNDERSTORMS. IN THE COLUMBIA
BASIN, BREEZY WINDS WILL DEVELOP AHEAD OF THE PRECIPITATION LATE
THIS AFTERNOON, WITH WIND GUSTS GENERALLY REMAINING LESS THAN
35 MPH.
TUESDAY, SHOWER ACTIVITY WILL RETREAT MOSTLY TO THE MOUNTAIN
AREAS AND BLUE MOUNTAIN FOOTHILLS AS NORTHWEST FLOW ALOFT
DEVELOPS BEHIND THE TROUGH AXIS EXIT. WEAK INSTABILITY WILL
DEVELOP ACROSS THE WA CASCADE CREST, FAR NORTHEAST OR, AND
SOUTHEAST WA LATE IN THE MORNING AND AFTERNOON TUESDAY,
RESULTING IN A SLIGHT CHANCE (15-20%) OF ISOLATED THUNDERSTORMS.
HOWEVER, THUNDERSTORM ACTIVITY IS EXPECTED TO DIMINISH LATE IN
THE AFTERNOON AS THE TROUGH LIFTS INTO MT. OTHERWISE, WIDESPREAD
BREEZY SOUTHWEST TO WEST WINDS (15-25 MPH WITH GUSTS UP TO 40
MPH) WILL DEVELOP TONIGHT THROUGH TOMORROW AS A COLD FRONT
BOUNDARY PASSAGE TIGHTENS PRESSURE GRADIENTS ACROSS THE FORECAST
AREA. IN THE LOWER ELEVATIONS, THE STRONGEST WINDS (SUSTAINED
WINDS 25-35 MPH WITH GUSTS UP TO 50 MPH) ARE EXPECTED TO DEVELOP
ACROSS PORTIONS OF NORTH CENTRAL OR, THE EASTERN COLUMBIA RIVER
GORGE, SIMCOE HIGHLANDS, OR COLUMBIA BASIN, OR BLUE MTN
FOOTHILLS, AND THE KITTITAS VALLEY.
BY WEDNESDAY, THE TROUGH WILL SLIDE FURTHER EAST OF THE REGION
WHILE UPPER LEVEL RIDGING WILL DEVELOP OVER THE NORTHEAST
PACIFIC. ANY LINGERING SHOWER ACTIVITY OVER THE MOUNTAINS WILL
DIMINISH BY THE AFTERNOON AS THE REGION COMES UNDER THE
INFLUENCE OF THE UPPER RIDGE OFFSHORE. BREEZY TO LOCALLY BREEZY
WINDS WILL CONTINUE INTO WEDNESDAY EVENING, BUT WILL BECOME
LIGHT WEDNESDAY NIGHT INTO THURSDAY.
THURSDAY THROUGH SUNDAY: LATE IN THE WORK WEEK THROUGH THE
WEEKEND, THERE IS GREAT AGREEMENT AMONGST ENSEMBLE GUIDANCE IN
WARMER AND DRIER CONDITIONS DEVELOPING AS UPPER LEVEL RIDGING
CONTINUES TO BUILD OFFSHORE THE PACNW. THAT SAID, UNCERTAINTY
DOES GROW IN THE AMPLITUDE AND POSITION OF THE RIDGE OFFSHORE.
WHILE ENSEMBLE CLUSTER SOLUTIONS ALL KEEP THE REGION DRY THROUGH
THIS PERIOD, ABOUT HALF OF THE MEMBERS KEEP THE UPPER RIDGE
FURTHER OFFSHORE WITH A NORTHERLY FLOW INTO THE INTERMOUNTAIN
PACNW. THESE SOLUTIONS ALSO FAVOR A SHORTWAVE TROUGH TO CLIP THE
REGION, WHICH WOULD INCREASE WINDS IN THE LOWER ELEVATIONS AND
BRING ELEVATED FIRE WEATHER CONCERNS. THE OTHER HALF OF
SOLUTIONS KEEP THE RIDGE AXIS MUCH CLOSER WITH NORTHWEST FLOW
OVER THE REGION. THIS SOLUTION WOULD KEEP THE TREND OF LIGHT
WINDS, BUT WOULD FAVOR INCREASED WARMING ACROSS THE FORECAST
AREA OVER THE WEEKEND. SPEAKING OF TEMPERATURES, THE NBM SHOWS A
40-60% CHANCE OF AREAS OF THE COLUMBIA BASIN/GORGE AND YAKIMA
VALLEY REACHING 90 DEGREES SATURDAY, WITH A WIDESPREAD 40-75%
CHANCE OF 90 DEGREES ACROSS MOST LOWER ELEVATION LOCATIONS
SUNDAY. LAWHORN/82
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
AN UPPER LEVEL LOW SPREADING ACROSS THE AREA WITH A SURFACE
ATTENDANT COLD FRONT IS BRINGING SCATTERED RAIN SHOWERS TO THE
AREA. PROBABLY THE MOST IMPACTFUL WEATHER FOR THE TERMINALS
WILL BE THE WINDS RESULTING FROM THIS SYSTEM THROUGH TUESDAY.
THE TIME WINDOW FOR THE STRONGEST WEST SOUTHWESTERLY GUSTY WINDS
WILL BEGIN EARLY TUESDAY MORNING THROUGH TUESDAY AFTERNOON. ANY
RISK OF IFR CEILINGS LOOKS TIED TO THE HIGHER TERRAIN AND NOT
NEAR THE LOWER ELEVATION TERMINALS GOING FORWARD OVERNIGHT (HIGH
CONFIDENCE 90%) AND LIKEWISE WITH RESPECT TO VISIBILITY, THE
ENSEMBLES ALL POINT TO KEEPING CHANCES FOR 3SM OR LOWER VSBY
RELEGATED TO HIGHER MOUNTAIN TERRAIN. LOOK FOR OCCASIONAL
SHOWERS OVERNIGHT WITH LIMITED TO NO FLIGHT CATEGORY IMPACTS.
PRELIMINARY POINT TEMPS/POPS
PDT 49 68 43 69 / 90 10 10 10
ALW 52 67 47 69 / 100 60 20 20
PSC 48 73 44 75 / 80 10 0 0
YKM 48 70 42 74 / 90 10 0 0
HRI 48 70 44 72 / 80 10 0 0
ELN 45 63 39 65 / 100 40 10 0
RDM 43 65 33 68 / 40 0 0 0
LGD 46 63 41 64 / 90 50 30 40
GCD 43 67 38 65 / 80 10 0 0
DLS 53 67 49 70 / 90 30 10 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...WIND ADVISORY FROM 2 AM TO 11 PM PDT TUESDAY FOR WAZ024-521.
WIND ADVISORY FROM 8 AM TO 11 PM PDT TUESDAY FOR WAZ026.
OR...WIND ADVISORY FROM 2 AM TO 11 PM PDT TUESDAY FOR ORZ041-044-
508.
WIND ADVISORY FROM 8 AM TO 11 PM PDT TUESDAY FOR ORZ507.
WIND ADVISORY UNTIL 5 PM PDT TUESDAY FOR ORZ510.
DISCUSSION...82
AVIATION...71
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