555
FXUS66 KPDT 282145
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
245 PM PDT TUE JUL 28 2026
KEY MESSAGES
- MOSTLY WARM, DRY CONDITIONS PERSIST THROUGH THE NEXT FEW DAYS.
- ELEVATED FIRE WEATHER CONDITIONS FOR WIND/LOW RH CONTINUE.
- SMALL CHANCE (0-10%) OF DRY THUNDERSTORM DEVELOPMENT ACROSS
THE SOUTHERN BLUES AND EASTERN MOUNTAINS WEDNESDAY AND
THURSDAY.
DISCUSSION
CURRENT SATELLITE SHOWS A FEW CUMULUS CLOUDS ACROSS THE CASCADES
WITH MOSTLY SUNNY CONDITIONS ACROSS MOST OF THE REGION. SMOKE
AND HAZE ORIGINATING FROM WILDFIRES IN CENTRAL OREGON THROUGH
PARTS OF THE SOUTHERN BLUES IS CLEARLY VISIBLE STREAMING FROM
THE SW TO NE, BRINGING HAZY CONDITIONS ACROSS THE COLOMBIA
BASIN. AN AIR QUALITY ADVISORY INITIATED VIA THE DEPARTMENT OF
ENVIRONMENTAL QUALITY IS IN EFFECT THROUGH MUCH OF THE COLOMBIA
BASIN AND BLUE MOUNTAINS THROUGH NOON TOMORROW DUE TO ONGOING
SMOKE TRANSPORT.
SYNOPTICALLY, SOUTHWEST FLOW CONTINUES AND WILL PERSIST THROUGH
THE NEXT COUPLE OF DAYS AS A TROUGH JUST OFFSHORE OF BRITISH
COLOMBIA PAVES WAY THROUGH THE PACNW THROUGH FRIDAY EVENING.
PERIODS OF EMBEDDED SHORTWAVES WITHIN THE TROUGH WILL BRING VERY
LOW CHANCES OF DRY THUNDERSTORM DEVELOPMENT (0 TO 10 PERCENT
CHANCE) ACROSS PORTIONS OF THE SOUTHERN BLUES AND EASTERN
MOUNTAINS, POTENTIALLY TRIGGERING NEW IGNITIONS.
DETERMINISTICS WEDNESDAY AND THURSDAY ADVERTISE A POCKET OF
VERY SLIGHT MOIST AIR WITH 45-65% RH IN THE LOW TO MID LEVELS
PASSING THROUGH THE SOUTHERN BLUES AND EASTERN MOUNTAINS, ALONG
WITH 150-300 J/KG OF MUCAPE DEVELOPING DURING PEAK HEATING
ACCORDING TO THE REFS. PRECIPITABLE WATER VALUES STAY AT BELOW
1.00 INCH IN THE DEVELOPMENT REGION (80-90% CHANCE), SUGGESTING
ANY THUNDERSTORM THAT INITIATE WILL BE MOSTLY DRY IN NATURE
WITH LITTLE TO NO POTENTIAL FOR WETTING RAINS TO OCCUR.
AS THE TROUGH APPROACHES THE AREA EARLY SATURDAY MORNING TO
AFTERNOON, TIGHT PRESSURE GRADIENTS WILL DEVELOP AND BRING GUSTY
TO LOCALLY WINDY CONDITIONS ACROSS THE REGION. AREAS ACROSS THE
KITTITAS/YAKIMA VALLEY'S, COLUMBIA BASIN OF OREGON, AND THE
CASCADE GAP REGION HAVE THE GREATEST CHANCE OF EXCEEDING WIND
ADVISORY CRITERIA (>45 MPH GUSTS) SATURDAY. CHANCES OF
EXCEEDANCE REACHES 50-80% ACROSS THE MENTIONED AREAS, WITH WIND
HIGHLIGHTS POSSIBLE AS WE GET CLOSER TO THE EVENT. THIS WILL
ALSO CONSEQUENTLY ENABLE TO THE POTENTIAL OF ELEVATED TO
CRITICAL FIRE WEATHER CONDITIONS DEVELOPING SATURDAY. JOINT
PROBABILITIES OF 25% OR LESS HUMIDITY AND SUSTAINED WINDS OF 20
MPH OR MORE ARE ADVERTISED AT 15-35% CHANCES BY 5 PM SATURDAY.
WILL MONITOR FOR THE TREND GOING THROUGH TOMORROW TO SEE IF FIRE
WEATHER HIGHLIGHTS ARE WARRANTED.
AVIATION /00Z TAFS THROUGH 00Z THURSDAY/
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD, AT ALL
SITES EXCEPT ALW. AT ALW MVFR CONDITIONS HAVE MOVED IN DUE TO
SMOKE FROM WILDFIRES. LOWER CONDITIONS FROM SMOKE CAN NOT BE
RULED OUT AT OTHER SITES EITHER. WINDS WILL GUST 20 TO 25 KTS AT
ALL TERMINALS THROUGH THIS EVENING THEN DECREASE TO 10 KTS OR
LESS.
PRELIMINARY POINT TEMPS/POPS
PDT 54 86 56 88 / 0 0 0 0
ALW 59 88 60 90 / 0 0 0 0
PSC 56 90 57 91 / 0 0 0 0
YKM 55 89 56 90 / 0 0 0 0
HRI 56 89 58 90 / 0 0 0 0
ELN 51 85 54 85 / 0 0 0 0
RDM 47 88 47 88 / 0 0 0 0
LGD 53 90 54 91 / 0 0 0 0
GCD 52 93 53 94 / 0 0 0 0
DLS 58 87 58 86 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...AIR QUALITY ALERT UNTIL NOON PDT WEDNESDAY FOR ORZ041-044-049-
050-502-503-505>511.
DISCUSSION...95
AVIATION...77
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