495
FXUS66 KPDT 261055
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
255 AM PST THU FEB 26 2026
KEY MESSAGES
- BREEZY AFTERNOON WINDS TODAY AND FRIDAY.
- DRY AND WARMING THROUGH THE WORKWEEK.
- NEXT CHANCE OF PRECIPITATION RETURNS OVER THE WEEKEND.
DISCUSSION
CURRENT RADAR AND INFRARED SATELLITE IMAGERY SHOWS DRY
CONDITIONS UNDER CLEAR SKIES. THIS IS IN RESPONSE TO THE UPPER
LEVEL RIDGE BUILDING JUST OFFSHORE TO ALLOW FOR SURFACE HIGH
PRESSURE TO PUSH ONSHORE AND THROUGH THE PACIFIC NORTHWEST.
ANOTHER SUNNY DAY EXPECTED ACROSS THE COLUMBIA BASIN TODAY,
LEADING TO PRESSURE GRADIENTS RETURNING ACROSS THE CASCADES TO
ALLOW FOR BREEZY WINDS TO DEVELOP ACROSS THE EAST SLOPES OF THE
WASHINGTON CASCADES, SIMCOE HIGHLANDS, BLUE MOUNTAIN FOOTHILLS,
LOWER COLUMBIA BASIN, AND THE YAKIMA/KITTITAS VALLEYS THIS
AFTERNOON. DEVELOPING SURFACE LOW PRESSURE OVER THE COLUMBIA
BASIN, AS A RESULT OF CLEAR SKIES AND EFFICIENT WARMING DUE TO
DOWNSLOPING DRY AIR, WILL ALSO HELP TO ENHANCE THE PRESSURE
GRADIENT - ESPECIALLY THROUGH THE KITTITAS VALLEY AND THE
SIMCOE HIGHLANDS. THIS WILL LEAD TO WIND GUSTS OF UP TO 40 MPH
THIS AFTERNOON ACROSS THESE ZONES, WITH 25-35 MPH GUSTS EXPECTED
THROUGH THE LOWER COLUMBIA BASIN AND BLUE MOUNTAIN FOOTHILLS.
ELLENSBURG DID BRIEFLY EXPERIENCE ADVISORY-LEVEL GUSTS (46 MPH
GUST AROUND 1 PM) YESTERDAY, BUT THE ABSENCE OF A DEPARTING
FRONTAL SYSTEM SHOULD RELAX THE PRESSURE GRADIENT ENOUGH TO KEEP
GUSTS SUB-ADVISORY THIS AFTERNOON. FRIDAY'S WINDS MAY BE A
DIFFERENT STORY, AS AN UPPER LEVEL TROUGH AND COLD FRONT PASS
THROUGH BRITISH COLUMBIA AND MAY ENHANCE THE PRESSURE GRADIENT
OVER THE CASCADES. THIS IS EVIDENT IN THE NBM'S ANALYSIS WITH
ADVISORY WIND GUSTS BEING ACHIEVED WITH THE 95TH PERCENTILE (1
IN 20 CHANCE) TODAY AND THE 90TH PERCENTILE (1 IN 10 CHANCE) ON
FRIDAY FOR ELLENSBURG. IN COMPARISON, YESTERDAY'S 07Z NBM RUN
SUGGESTED ADVISORY-LEVEL WINDS (45 MPH OR GREATER) AT ELLENSBURG
AT THE 90TH PERCENTILE.
THE PRESENCE OF THE UPPER LEVEL RIDGE WILL KEEP SKIES CLEAR AND
TEMPERATURES WARMING THROUGH FRIDAY. HIGH TEMPERATURES ARE
EXPECTED TO REACH INTO THE MID-TO UPPER 50S TODAY AND THE UPPER
50S TO LOW 60S FRIDAY ACROSS THE LOWER COLUMBIA BASIN, BLUE
MOUNTAIN FOOTHILLS, AND CENTRAL OREGON - WHICH IS ABOUT 5
DEGREES WARMER THAN NORMAL. THESE WARMER CONDITIONS, COUPLED
WITH DOWNSLOPING AND DRY WINDS, WILL LEAD TO AFTERNOON
HUMIDITIES ACROSS CENTRAL OREGON, BLUE MOUNTAIN VALLEYS, NORTH-
CENTRAL OREGON, AND PORTIONS OF THE COLUMBIA BASIN DROPPING TO
BETWEEN 15-30% BOTH TODAY AND FRIDAY. MODERATE TO GOOD (40-65%)
OVERNIGHT HUMIDITIES ARE ANTICIPATED THROUGH THE WORKWEEK, WITH
FRIDAY BEING THE DRIER DAY AS THE UPPER LEVEL RIDGE MOVES
ONSHORE.
THE UPPER LEVEL LOW PRESSURE THAT CUTOFF FROM THE OVERALL FLOW
AND PUT A HALT TO SHOWERS EARLIER IN THE WEEK WILL RETURN AS A
WEAKENING SYSTEM OVER THE WEEKEND. THIS WILL BRING PRECIPITATION
ACROSS CENTRAL OREGON SATURDAY THROUGH SUNDAY MORNING. AS
ANTICIPATED IN WEDNESDAY MORNING'S DISCUSSION, PRECIPITATION
AMOUNTS HAVE TRENDED UPWARDS (0.01-0.06" UP FROM 0.01-0.02" 24
HOURS AGO) AND EXTENT HAS PUSHED SLIGHTLY FURTHER NORTH TO
INCLUDE PORTIONS OF THE JOHN DAY BASIN AND THE BEND/REDMOND
AREAS. THESE TRENDS WERE EVIDENT IN THE INCREASING STRENGTH OF
THE INCOMING UPPER LEVEL LOW VIA THE ECMWF AND GFS AI ENSEMBLES,
WHICH IS STILL PREVALENT IN THE ECMWF AI ENSEMBLES. LREF
ENSEMBLE CLUSTERS HAVE ALSO ALLUDED TO THIS AS 87% OF MEMBERS
NOW BRING MEASURABLE RAINFALL (0.01" OR GREATER) INTO PORTIONS
OF WALLOWA AND UNION COUNTIES ON SATURDAY. THIS MAY CONTINUE TO
TREND IN THIS DIRECTION IN SUBSEQUENT MODEL RUNS, BUT WITH THE
LACK OF OVERALL CONSISTENCY IN AI ENSEMBLES (GFS WEAKENING
INCOMING SYSTEM FROM PREVIOUS RUNS) THE TREND IS LIKELY TO SLOW.
REGARDLESS, OVERALL IMPACTS WILL BE MINIMAL AS SNOW LEVELS WILL
HOVER BETWEEN 4500-6500 FEET BOTH DAYS.
HIGH PRESSURE RETURNS MONDAY IN THE WAKE OF THE PASSING WEEKEND
SYSTEM, BRINGING DRY AND WARM CONDITIONS BACK TO THE AREA AS
HIGHS PEAK IN THE UPPER-50S TO LOW-60S ACROSS CENTRAL OREGON,
BLUE MOUNTAIN FOOTHILLS, AND THE LOWER COLUMBIA BASIN ON
TUESDAY. GUIDANCE IS IN GOOD AGREEMENT WITH A MORE SUBSTANTIAL
UPPER LEVEL TROUGH AND ASSOCIATED COLD FRONT PASSING THROUGH THE
PACIFIC NORTHWEST ON WEDNESDAY, WITH 82% OF LREF ENSEMBLES
SHOWCASING WIDESPREAD PRECIPITATION. SNOW LEVELS LOOK TO DROP TO
BETWEEN 4000-5000 FEET ON WEDNESDAY, ALLOWING FOR OUR MOUNTAIN
ZONES TO PICK UP 1-3 INCHES. CONFIDENCE IN THESE SNOW AMOUNTS IS
CURRENTLY LOW (20-30%) AS OVERALL STRENGTH OF THE INCOMING
SYSTEM IS STILL IN QUESTION (56% OF ENSEMBLE MEMBERS HINT AT
STRONGER SYSTEM THAT CURRENT FORECAST). STAY TUNED. 75
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
VFR CONDITIONS CURRENTLY ACROSS ALL SITES, WHICH WILL STAY THE
COURSE THROUGH THE PERIOD. WINDS WILL INCREASE THROUGH THE
MORNING AND PEAK THROUGH THE AFTERNOON AS VALUES BETWEEN 10-15
KTS ARE LIKELY AT KPSC/KALW/KPDT/KDLS. ELSEWHERE, WINDS SHOULD
STAY BELOW 10 KTS. 25KFT FEW-SCT CEILINGS WILL DEVELOP THROUGH
THE AFTERNOON ACROSS ALL TERMINALS, CLEARING THROUGH THE
EVENING. 75
PRELIMINARY POINT TEMPS/POPS
PDT 31 56 32 50 / 0 0 0 0
ALW 35 55 35 51 / 0 0 0 0
PSC 32 57 31 52 / 0 0 0 0
YKM 29 53 31 50 / 0 0 0 0
HRI 31 57 31 52 / 0 0 0 0
ELN 30 48 30 48 / 0 0 0 0
RDM 25 58 28 54 / 0 0 0 10
LGD 29 56 31 54 / 0 0 0 10
GCD 28 55 32 55 / 0 0 0 10
DLS 33 55 33 52 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...NONE.
DISCUSSION...75
AVIATION...75
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