314
FXUS66 KPDT 270543
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1043 PM PDT SUN JUL 26 2026
.UPDATED AVIATION DISCUSSION.
KEY MESSAGES
- QUIET, DRY WEATHER WITH DIURNAL WINDS/BREEZES THROUGH
THIS WEEK.
- ELEVATED FIRE WEATHER CONDITIONS/CONCERNS CONTINUE WITH
BREEZY WINDS AND LOW RH PERSISTING.
- AIR QUALITIES ADVISORIES/ALERTS PERSIST THROUGH MONDAY.
DISCUSSION
A MEAN UPPER TROUGH WAS IN PLACE WITH A CENTER OF LOW PRESSURE
AT 500 MB OFF THE NRN BC COAST. SOUTHWEST FLOW ALOFT ACROSS
THE PACIFIC AND INTERIOR NW TODAY IS RESULTING IN A SURFACE
RIDGE OF HIGH PRESSURE ACROSS THE COASTAL OREGON AREAS AND
ACROSS THE COLUMBIA BASIN OF WA/OR. THIS WILL LARGELY RESULT IN
LIGHT TO SLIGHTLY BREEZY WINDS OVER THE NEXT COUPLE OF DAYS WITH
TERRAIN DRIVEN WINDS OVERNIGHT AS BOUNDARY LAYER MIXING CEASES.
ON MONDAY MOST OF OF THE MIDDLE RANGE MODELS (EC/HI-RES ARW,
GFS NAM), ARE SHOWING A STRONGER COMPACT VORTICITY CORE MOVE
INTO THE BASE OF THE UPPER TROUGH AND THAT SHOULD PROMOTE A
FRONTAL PASSAGE FOR THE REGION MONDAY NIGHT AND TUESDAY, WHICH
WILL HAVE LITTLE IMPACT ON TEMPERATURES BUT KEEP WEATHER TEMPS
STEADY THOUGH MID WEEK. IT MAY UPTICK THE MOISTURE PROFILES
TUESDAY BEFORE A DRYING OUT (LOWER DEW POINTS) BEGINS WEDNESDAY,
ALLOWING TEMPERATURES TO BEGIN TO RISE EACH AFTERNOON BACK
THROUGH THE LOW TO MID 90S, PEAKING ON FRIDAY. MODELS ARE
LEANING TOWARD A FRONTAL PASSAGE AFTER FRIDAY THAT WOULD LEAVE
MORE WINDY CONDITIONS ACROSS THE GREATER AREA WITH INCREASED
RISK FOR FIRE WEATHER IMPACT LEVELS BASED ON LOW RH AND WINDS.
IN THE MEANTIME, AQI REMAINS IN THE 150 TO 500 RANGE ACROSS IN
THE VICINITY OF THE LARGER FIRES ACROSS THE BLUE MOUNTAINS AND
ADJACENT FOOTHILLS ZONES, AND AIR QUALITY ADVISORIES REMAINS IN
EFFECT FOR THESE AREAS FROM CENTRAL OREGON TO THE WALLOWAS AS
WELL AS SOUTHEAST WASHINGTON/WALLA WALLA COUNTY TO THE TRI
CITIES EAST OF THE COLUMBIA RIVER . THE AIR QUALITY ADVISORIES
ARE IN EFFECT THOUGH MONDAY AFTERNOON AND MAY BE EXTENDED BASED
ON DEQ EVALUATION.
AVIATION /06Z TAFS THROUGH 06Z TUESDAY/
VFR CONDITIONS CURRENTLY ACROSS ALL SITES, WHICH WILL STAY THE
COURSE THROUGH THE PERIOD. HAZE/SMOKE FROM NEARBY WILDFIRES WILL
DROP VISIBILITIES TO 6SM AT KPDT OVERNIGHT THROUGH MUCH OF THE
DAY ON MONDAY. WINDS CONTINUE TO SUBSIDE THIS EVENING, BUT
BREEZY WINDS OF 10-20KTS WITH GUSTS OF 20-25KTS WILL RETURN FOR
KDLS/KRDM/KBDN THROUGH THE AFTERNOON. 75
FIRE WEATHER
NO RED FLAG WARNINGS ARE ANTICIPATED FOR THIS FORECAST/MODEL
CYCLE. THE AREAS SOUTH AND WEST OF OF WHITE SWAN/HARRAH/TOPPENISH
COULD SEE METEOROLOGICAL RED FLAG CONDITIONS BRIEFLY LATE THIS
AFTERNOON INTO EARLY EVENING THAT COULD LAST AS LITTLE AS AN HOUR
IN ANY LOCATIONS ALONG THE FIRE ZONE 694/691 INTERFACE. FOR
MONDAY RELATIVE HUMIDITY WILL CONTINUE TO BE VERY DRY TO CRITICAL
ACROSS THE OR/WA691 ZONES TO THE WALLOWAS AND GRAND RONDE VALLEY
EASTERN OR700 AND THE JOHN DAY BASIN, BUT LACKING WINDS. THE
REVERSE IS TRUE OVER CENTRAL OREGON AND AND NORTHERN CENTRAL
OREGON WHERE BREEZY CONDITIONS MEETS A LITTLE MORE MOISTURE TO
PREVENT RED FLAG.
PRELIMINARY POINT TEMPS/POPS
PDT 59 88 57 87 / 0 0 0 0
ALW 63 90 63 89 / 0 0 0 0
PSC 62 92 61 91 / 0 0 0 0
YKM 58 91 59 89 / 0 0 0 0
HRI 62 91 61 89 / 0 0 0 0
ELN 56 84 56 81 / 0 0 0 0
RDM 54 88 50 87 / 0 0 0 0
LGD 60 90 56 89 / 0 0 0 0
GCD 57 92 54 92 / 0 0 0 0
DLS 61 88 62 84 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...AIR QUALITY ALERT UNTIL 11 AM PDT MONDAY FOR WAZ028>030.
OR...AIR QUALITY ALERT UNTIL NOON PDT MONDAY FOR ORZ049-050-502-503-
505-506-508-509-511.
DISCUSSION...77
AVIATION...75
FIRE WEATHER...71
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