735
FXUS66 KPDT 251721
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1021 AM PDT THU JUN 25 2026
KEY MESSAGES
- MULTIPLE RED FLAG WARNINGS IN EFFECT TODAY DUE TO BREEZY
WINDS AND LOW RELATIVE HUMIDITY
- COOLER, BREEZY, AND SHOWERY WEATHER IS LIKELY (95 PERCENT
CONFIDENCE) FRIDAY INTO THE WEEKEND
- CHANCE OF THUNDERSTORMS FOR THE BLUE MOUNTAINS ON FRIDAY, WITH
A VERY LOW CHANCE (5-14 PERCENT) TO SLIGHT CHANCE (15-24
PERCENT) ELSEWHERE
DISCUSSION
COOLER TEMPERATURES ARE EXPECTED THIS AFTERNOON BY 5 TO 10
DEGREES ON AVERAGE AS MORE DENSE SKY COVER OVERSPREADS THE
REGION DURING THE AFTERNOON IN ADVANCE OF AN UPPER LEVEL LOW AND
WESTERLY JET OVER THE NORTHEAST PACIFIC SPREADING WESTERLY
DIFFLUENT MID LEVEL FLOW ACROSS THE CASCADE RANGE. THIS WILL
BRING ISOLATED TO SCATTERED MOUNTAIN SHOWERS TO THE CASCADES
CREST MAINLY THIS EVENING WITH LOW ENOUGH INSTABILITY THAT
THUNDERSTORMS ARE NOT SHOWING UP ACROSS THE HREF MEMBERS.
BROADER, STRONGER SURFACE WINDS INDICATED BY THE NBM SHOWING 25
TO 35 KNOTS (ROUGHLY 30 TO 40 MPH) ARE SEEN ACROSS THE SIMCOE
HIGHLANDS, AND LOWER COLUMBIA BASIN/RIVER GORGE THIS AFTERNOON,
WITH BREEZY CONDITIONS IN ALL OTHER OTHER ZONES, BARRING THE
EASTERN MOUNTAINS. THE COOLEST TEMPERATURES OF THE NEXT 7 DAYS
FALL OVER THE WEEKEND, AS THE EC/GFS AND CANADIAN MODELS ALL
DRIVE A SECOND SHORTWAVE FARTHER SOUTH INTO SW OREGON/NRN CA
HELPING TO CARVE OUT THE UPPER LOW BROADLY OVER THE INTERIOR NW
WITH UNSEASONABLY COOL AIR ALOFT (560DM 500 MB LOW).
PRECIPITATION PROBABILITIES JUMP TO 90% ACROSS THE CASCADES AND
EASTERN MOUNTAINS BY FRIDAY AFTERNOON AND EVENING AND BEGINS TO
BACK OFF OVER THE WEEKEND.
AVIATION /18Z TAFS THROUGH 18Z FRIDAY/
VFR CONDITIONS ARE FORECAST AT ALL SITES FOR THE NEXT 24 HOURS.
CIGS WILL LOWER THROUGH THE DAY AS A LOW-PRESSURE SYSTEM
APPROACHES FROM THE PACIFIC, AND RAIN SHOWERS ARE FORECAST TO
SPREAD EAST OF THE CASCADES LATER THIS AFTERNOON/EARLY EVENING
INTO THE OVERNIGHT HOURS. CANNOT RULE OUT SUB-VFR CIGS, BUT
CONFIDENCE IS LOW AT LESS THAN 30 PERCENT FOR ALL SITES. WINDS
WILL BECOME BREEZY TODAY WITH LIGHTER WINDS RETURNING OVERNIGHT
FOR MOST SITES.
FIRE WEATHER
DESPITE INCREASING CLOUD COVER AND NOT QUITE AS HOT
TEMPERATURES, CRITICAL FIRE WEATHER IS POSSIBLE TO LIKELY ACROSS
SEVERAL ZONES THIS AFTERNOON. THE BREEZIER TO GUSTY WINDS WILL
BE THE TIPPING POINT AS AN INCOMING SYSTEM AIDS THE DEVELOPMENT
OF GAP WINDS AND GUSTY WINDS ACROSS THE LOWER COLUMBIA BASIN.
WENT AHEAD AND ADDED WA694 TO THE GROUP OF RED FLAG WARNED
ZONES AS EASTERN SECTIONS OF THIS ZONE CAME IN WITH 70-80%
CONFIDENCE IN 25% OR LESS RH AND 15 MPH OR HIGHER WINDS THIS
AFTERNOON, ESPECIALLY WESTERN SECTIONS OF THE TOPPENISH RIDGE
AND VICINITY. NO OTHER CHANGES TO PREVIOUS RED FLAGS, WHICH
INCLUDE OR703, OR/WA691 AND WA690. FOR FRIDAY, THE BREEZY
WINDS CONTINUE HOWEVER RELATIVE HUMIDITY LEVELS DROP OUT OF THE
CRITICAL CRITERIA. AS THE COOLER AIR ALOFT MOVES IN OVER THE
NEXT 2-3 DAYS, INCREASED WETTING RAIN OPPORTUNITY UNFOLDS FRIDAY
AFTERNOON AND OVERNIGHT INTO SATURDAY MORNING FOR THE HIGHER
ELEVATION MOUNTAIN ZONES.
PRELIMINARY POINT TEMPS/POPS
PDT 85 52 75 46 / 0 50 50 30
ALW 87 58 76 52 / 0 30 50 30
PSC 89 56 80 51 / 0 30 20 10
YKM 86 55 79 50 / 0 30 10 10
HRI 87 54 78 49 / 0 50 30 10
ELN 81 50 71 45 / 0 20 30 10
RDM 82 46 71 39 / 0 60 20 30
LGD 85 53 70 47 / 0 50 90 90
GCD 86 51 71 43 / 0 70 90 90
DLS 83 56 75 53 / 0 60 20 10
PDT WATCHES/WARNINGS/ADVISORIES
WA...RED FLAG WARNING UNTIL 8 PM PDT THIS EVENING FOR WAZ694.
RED FLAG WARNING UNTIL 9 PM PDT THIS EVENING FOR WAZ690-691.
OR...RED FLAG WARNING UNTIL 9 PM PDT THIS EVENING FOR ORZ691.
RED FLAG WARNING UNTIL 8 PM PDT THIS EVENING FOR ORZ703.
DISCUSSION...71
AVIATION...86
FIRE WEATHER...71
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