971
FXUS66 KPDT 072141
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
241 PM PDT WED OCT 7 2026
KEY MESSAGES
- ABOVE NORMAL TEMPERATURES AND DRY THROUGH THURSDAY.
- BREEZY WINDS WITH ISOLATED FIRE WEATHER CONCERNS FRIDAY.
- CHILLY MORNING TEMPERATURES AND RAIN CHANCES OVER THE WEEKEND.
DISCUSSION
CURRENT RADAR AND VISIBLE SATELLITE IMAGERY SHOWS DRY CONDITIONS
UNDER CLEAR SKIES. THIS IS A RESULT OF AN UPPER LEVEL RIDGE
LOCATED JUST OFFSHORE. THE RIDGE WILL BEGIN TO TRACK WEST AND
FURTHER INTO THE EASTERN PACIFIC INTO THURSDAY, OPENING THE DOOR
TO AN INCOMING SYSTEM ORIGINATING FROM THE GULF OF ALASKA LATE
IN THE WEEK. THE APPROACHING SYSTEM WILL SHIFT WINDS ALOFT FROM
THE NORTHWEST TO MORE FROM THE WEST ON THURSDAY TO ALLOW FOR A
SLIGHT 2 TO 4 DEGREE INCREASE IN HIGH TEMPERATURES. HIGHS WILL
PEAK IN THE LOW TO MID-80S ACROSS CENTRAL OREGON AND OVER THE
MAJORITY OF THE COLUMBIA BASIN. A WEAK THERMAL TROUGH WILL ALSO
DEVELOP ON THURSDAY, HELPING TO FURTHER WARM TEMPERATURES AND
DRY CONDITIONS AS AFTERNOON HUMIDITIES DIP INTO THE MID-TEENS
ACROSS CENTRAL OREGON AND LOW-20S ACROSS LOWER ELEVATIONS OF
THE COLUMBIA BASIN.
THE APPROACHING SYSTEM WILL ALLOW FOR A PRESSURE GRADIENT TO
DEVELOP ALONG THE CASCADES ON FRIDAY, AS ADVERTISED BY A 11-13
MB GRADIENT BETWEEN PORTLAND AND SPOKANE VIA THE GFS, NAM, AND
SREF. THIS WOULD RELATE TO SUSTAINED WEST-NORTHWEST WINDS OF
23-28 MPH WITH GUSTS OF 35 TO 45 MPH ACROSS THE SIMCOE
HIGHLANDS, COLUMBIA GORGE, AND BLUE MOUNTAIN FOOTHILLS.
CURRENTLY, THE NBM SUGGESTS THE BEST CHANCES FOR ADVISORY LEVEL
WINDS (GUSTS OF 45 MPH OR GREATER) OCCURRING ACROSS THE SIMCOE
HIGHLANDS AT A 60-70% CHANCE, COMPARED TO A 30-40% CHANCE OVER
THE BLUE MOUNTAINS FOOTHILLS, AND A 20-30% CHANCE THROUGH THE
KITTITAS VALLEY. PEAK WINDS ARE EXPECTED BETWEEN 2PM AND 8PM.
THESE ELEVATED WINDS, COUPLED WITH THE DRY, INCUMBENT AIR MAY
LEAD TO ISOLATED FIRE CONTROL CONCERNS - ESPECIALLY OVER AREAS
OF CENTRAL OREGON AND NORTHERN WALLOWA COUNTY. ANOTHER, MORE
WIDESPREAD CONCERN ALSO ARISES UNDER THESE CONDITIONS - BLOWING
DUST. THERE IS A POTENTIAL FOR REDUCED VISIBILITY AS A RESULT OF
BLOWING DUST, WHICH COULD OCCUR ACROSS THE COLUMBIA BASIN,
COLUMBIA GORGE, AND THE YAKIMA/KITTITAS VALLEYS ON FRIDAY.
VISIBILITIES AS LOW AS ONE MILE IS POSSIBLE, AND MAY CHANGE
QUICKLY DUE TO THE PASSING COLD FRONT.
FRIGID TEMPERATURES ARE ANTICIPATED SATURDAY ONWARD AS NORTH
FLOW ALOFT EFFICIENTLY FUNNELS COLD, ARCTIC AIR INTO THE REGION
FROM NORTHERN BRITISH COLUMBIA, NORTHWEST TERRITORIES, AND YUKON
PROVINCES. THIS INCOMING AIRMASS WILL LEAD TO FREEZE POTENTIAL
FOR CENTRAL OREGON AND WALLOWA COUNTY SATURDAY MORNING, BECOMING
MORE WIDESPREAD SUNDAY AND MONDAY MORNING ACROSS THE COLUMBIA
BASIN. GUIDANCE STILL STRUGGLES WITH THE UPPER LEVEL TROUGH'S
STRENGTH, WHICH DIRECTLY RELATES TO HOW EFFICIENT COLD AIR
ADVECTS INTO THE AREA FROM THE NORTH. CURRENTLY, 52% OF ENSEMBLE
MEMBERS ADVERTISE A STRONGER SYSTEM, WHICH LEADS TO A COLDER
SCENARIO BOTH SUNDAY AND MONDAY MORNINGS. A STRONGER SYSTEM
WOULD ALSO BETTER TAP INTO MOISTURE ASSOCIATED WITH THE REMNANTS
OF HURRICANE RACHEL AS IT PROGRESSES NORTH AND TRANSITIONS TO
POST-TROPICAL STATUS. OVERALL, RAIN AMOUNTS ARE EXPECTED TO BE
LIMITED TO AROUND 0.05" FOR LOWER ELEVATIONS AND A WETTING RAIN
FOR THE CASCADE AND BLUE MOUNTAINS. THE COLDER INCOMING AIR WILL
ALSO DECREASE SNOW LEVELS TO BETWEEN 3000 AND 4000 FEET,
BRINGING THE FIRST ONE TO TWO INCHES OVER THE ELKHORNS. A LIGHT
DUSTING IS LIKELY OVER THE BLUES, CASCADES, AND JOHN DAY
HIGHLANDS SATURDAY NIGHT THROUGH MONDAY MORNING, WITH 88% OF
ENSEMBLE MEMBERS ALIGNING WITH THIS OUTCOME. 75
AVIATION /18Z TAFS THROUGH 18Z THURSDAY/
VFR CONDITIONS ARE FORECAST AT ALL SITES FOR THE NEXT 24 HOURS
(99% CONFIDENCE). DIURNALLY AND TERRAIN-DRIVEN WINDS OF 12 KTS
OR LESS ARE EXPECTED.
PRELIMINARY POINT TEMPS/POPS
PDT 46 80 50 72 / 0 0 0 0
ALW 52 81 56 72 / 0 0 0 0
PSC 46 82 48 75 / 0 0 0 0
YKM 50 81 50 70 / 0 0 0 0
HRI 45 81 49 73 / 0 0 0 0
ELN 48 79 49 63 / 0 0 0 0
RDM 40 82 41 71 / 0 0 0 0
LGD 46 83 47 74 / 0 0 0 0
GCD 48 86 47 76 / 0 0 0 0
DLS 53 85 53 70 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...NONE.
DISCUSSION...75
AVIATION...86
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