803
FXUS66 KPDT 241750
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1050 AM PDT MON AUG 24 2026
KEY MESSAGES
1. RIDGE OF HIGH PRESSURE OVERHEAD WILL KEEP TEMPERATURES ABOVE
SEASONAL NORMAL THROUGH WEDNESDAY
2. AN UPPER LEVEL LOW APPROACHING THE REGION WILL BRING INCREASED
WINDS WEDNESDAY INCREASING FIRE WEATHER CONCERNS.
DISCUSSION
CURRENT NIGHT TIME SATELLITE SHOWS LITTLE TO NO CLOUD COVER OVER THE
REGION. LOOKING AT OVERNIGHT TEMPERATURES TO BE INN THE UPPER 50S TO
LOW 60S THROUGH THE BASIN, GORGE AND ALONG THE FOOTHILLS OF THE
BLUES. ELSEWHERE WILL SEE LOW 50S.
MODELS SHOW A RIDGE OF HIGH PRESSURE BUILDING OVER THE REGION TODAY
AND PERSISTING THROUGH EARLY WEDNESDAY BRINGING WITH IT DRY AND
ABOVE SEASONAL AVERAGE TEMPERATURES. LOOKING AT IN HOUSE
CALCULATIONS, TEMPERATURES ARE EXPECTED TO BE ANYWHERE FROM 5 TO 10
DEGREES ABOVE SEASONAL AVERAGE TODAY, INCREASING TO NEAR 15 DEGREES
TOMORROW AND WEDNESDAY. LOOKING AT HEATRISK PROBABILITIES,
TUESDAY?WEDNESDAY WILL BE THE PEAK WITH 70-80% PROBABILITIES OF
AREAS REACHING MODERATE HEATRISK (LEVEL 2 OF 4) ACROSS THE COLUMBIA
BASIN AND CENTRAL OR. THERE IS ALSO A LOW TO MEDIUM RISK OF AREAS IN
THE COLUMBIA BASIN SEEING MAJOR HEATRISK (3 OF 4) WITH 20-40%
PROBABILITIES. MODERATE HEATRISK AFFECTS THOSE WHO ARE SENSITIVE TO
HEAT, ESPECIALLY THOSE WITHOUT COOLING/HYDRATION, WHILE MAJOR
HEATRISK AFFECTS ANYONE WITHOUT COOLING/HYDRATION.
WEDNESDAY MODELS SHOW THE UPPER LEVEL LOW OFF THE COAST OF THE PACNW
BEGIN TO PUSH ITS WAY ONSHORE. BY WEDNESDAY AFTERNOON, MODELS SHOW
THE LEADING EDGE OF THE LOW BEGINNING TO MOVE TOWARDS THE CASCADES.
AS THE LEADING EDGE OF THE LOW APPROACHES THE CASCADES, SHORT TERM
DETERMINISTIC MODELS SHOW A TIGHTENING OF THE PRESSURE GRADIENTS
ALONG THE CRESTS. LOOKING AT RAW ENSEMBLES, THERE IS 60-80%
CONFIDENCE FOR WINDS OF 15-25 MPH WITH GUSTS TO 35 MPH POSSIBLE
THROUGH THE COLUMBIA RIVER GORGE, KITTITAS VALLEY AND ALONG THE
FOOTHILLS OF THE BLUE MOUNTAINS.
WITH THE INCREASED WINDS AND NBM SHOWING RELATIVE HUMIDITIES BEING
IN THE TEENS TO LOW 20% ACROSS THE REGION, THERE IS ELEVATED TO
LOCALLY CRITICAL FIRE WEATHER CONCERNS THAT COULD DEVELOP ACROSS THE
LOWER ELEVATIONS ZONES (65-75%).
THURSDAY ONWARDS, MODELS SHOW THE UPPER LEVEL LOW TO CONTINUE TO
PERSIST JUST TO THE WEST OF THE CASCADES BRINGING PERSISTENT
SOUTHWESTERLY FLOW TO THE REGION. THIS WILL KEEP THE REGION UNDER
DRY AND BREEZY CONDITIONS.
AVIATION /18Z TAFS THROUGH 18Z TUESDAY/
VFR CONDITIONS TO
PREVAIL THROUGH THE PERIOD. LOW CONFIDENCE (15-20%) IN SMOKE
IMPACTS AT SITES, BUT HAVE INCLUDED HZ FU AT SITES ALW/PDT DUE
TO PROXIMITY TO AREA WILDFIRES. WINDS WILL BE LIGHT, 12KTS OR
LESS, THROUGH THE PERIOD. LAWHORN/82
FIRE WEATHER
FIRE WEATHER CONCERNS ARE MODERATE THROUGH THE FORECAST PERIOD
AS ONLY RELATIVE HUMIDITY IS LOW WITH NO WINDS. THE NEXT DAY OF
CONCERN FOR ELEVATED TO LOCALLY CRITICAL FIRE WEATHER CONCERNS
WILL BE WEDNESDAY AS AN UPPER LEVEL LOW BRINGS INCREASED WINDS
OF 15-25 MPH WINDS AND GUSTS TO 35 MPH WITH RELATIVE HUMIDITIES
IN THE TEENS TO LOW 20S.
PRELIMINARY POINT TEMPS/POPS
PDT 91 55 94 59 / 0 0 0 0
ALW 93 62 95 66 / 0 0 0 0
PSC 93 57 96 61 / 0 0 0 0
YKM 90 61 95 63 / 0 0 0 0
HRI 92 58 95 63 / 0 0 0 0
ELN 86 57 93 61 / 0 0 0 0
RDM 91 50 94 50 / 0 0 0 0
LGD 93 56 98 58 / 0 0 20 20
GCD 95 57 96 58 / 0 0 10 10
DLS 93 65 95 65 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...AIR QUALITY ALERT UNTIL NOON PDT WEDNESDAY FOR WAZ026-028>030-
522-523.
OR...AIR QUALITY ALERT UNTIL NOON PDT WEDNESDAY FOR ORZ044-502-503-
507.
DISCUSSION...90
AVIATION...82
FIRE WEATHER...90
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