519
FXUS66 KPDT 051707
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1007 AM PDT WED AUG 5 2026
KEY MESSAGES
- ELEVATED TO LOCALLY CRITICAL FIRE WEATHER CONDITIONS WILL
CONTINUE TO PERSIST THROUGH AT LEAST THE BETTER PART OF THIS
WEEK.
- WIDESPREAD MODERATE RISK OF HEAT EXPECTED TO DEVELOP THROUGH
THE REGION BY THURSDAY.
- SMOKE AND HAZE FROM LOCAL AND REGIONAL WILDLAND FIRES
CONTINUE TO SUPPRESS AIR QUALITY LEVELS THROUGH AT LEAST
THURSDAY.
DISCUSSION
SATELLITE & OTHER NIGHT TIME PRODUCTS CONTINUE TO SHOW
WIDESPREAD SMOKE AND HAZE ACROSS THE REGION FROM LOCAL AND
REGIONAL WILDLAND FIRES IGNITED OVER THE PAST FEW WEEKS. SMOKE
IS EXPECTED TO LINGER THROUGH AT LEAST THURSDAY (>90% CHANCE) AS
A RIDGE LOCATED OFFSHORE CONTINUES TO MOVE TOWARDS THE REGION
THROUGH THURSDAY. THIS HAS ALLOWED UNHEALTHY LEVELS OF AIR
QUALITY TO ACCUMULATE, THUS LOCAL AGENCIES FROM OREGON &
WASHINGTON HAVE ISSUED AIR QUALITY ALERTS/ADVISORIES FOR THE
ENTIRE FORECAST AREA.
WITH THE RIDGE AXIS EXPECTED TO REACH OVER THE AREA IN THE
THURSDAY/FRIDAY TIMEFRAME, WE EXPECT A WARMING TREND TO
CONTINUE UNTIL THEN WITH THE NBM ADVERTISING CHANCES OF REACHING
TRIPLE DIGITS IN PARTS OF THE COLUMBIA BASIN AT AROUND 30-50%.
GUIDANCE IS IN VERY GOOD AGREEMENT WITH HEATRISK VALUES REACHING
'MODERATE' WITH WIDESPREAD CHANCES OF 80-100%. ISOLATED AREAS OF
MAJOR HEATRISK IS POSSIBLE WITH 30-50% CHANCES POSSIBLE
THURSDAY & FRIDAY IN PARTS OF THE YAKIMA/KITTITAS REGION. WITH
THAT BEING SAID, WILDLAND FIRE SMOKE COULD INHIBIT THE RIDGE
BRINGING ITS FULL POTENTIAL OF HEAT. AREAS WITH THICKER COLUMNS
OF SMOKE MAY FALL SHORT SEVERAL DEGREES THAN OTHERWISE EXPECTED,
POSSIBLY TAPERING LEVELS BELOW MAJOR THAT WOULD'VE REACHED IT
OTHERWISE. THIS BRINGS ISSUING HEAT ADVISORIES AT A LOW
CONFIDENCE (10-30%) DUE TOO THE DIFFICULT TO FORECAST SMOKE
PLUMES IN THE AREA.
GUIDANCE IN THE SYNOPTIC LEVEL THROUGH THE WEEKEND IS IN GOOD
AGREEMENT THAT THE PATTERN WILL TURN INTO A ZONAL/QUASI-ZONAL
FLOW WITH TIGHTER PRESSURE GRADIENTS, RESULTING IN BREEZY TO
LOCALLY WINDY CONDITIONS DEVELOPING LATE THIS WEEK. WITH DRY AIR
LINGERING WITH MINIMUM RELATIVE HUMIDITIES STILL IN THE 10-18
PERCENT RANGE FRIDAY AND SATURDAY, CHANCES OF CRITICAL WEATHER
CONDITIONS DEVELOPING GO UP WITH 20-30% CONFIDENCE. THE MAIN
FACTOR IN INCREASED CONFIDENCE WILL BE HOW FAR AND WIDESPREAD
THE WINDS WILL BE. ALTHOUGH LOCAL AREAS ARE EXPECTED TO BE
CRITICAL, IT'S NOT ANTICIPATED IT WILL BE A WIDESPREAD EVENT,
THUS NO FIRE WEATHER HIGHLIGHTS WILL BE ISSUED FOR THE WEEKEND
AT THIS TIME.
AVIATION /18Z TAFS THROUGH 18Z THURSDAY/
WIDESPREAD SMOKE AND HAZE FROM LOCAL AND REGIONAL WILDLAND FIRES
CONTINUE TO IMPACT ALL TAF SITES THROUGH THE NEXT 24-HOURS.
SMOKE IS DENSE ENOUGH THAT MANY SITES ARE SEEING MVFR AND IFR
CONDITIONS. THIS WILL CONTINUE THROUGH THE PERIOD. WINDS ARE TO
LIGHT TO CLEAR THE SMOKE FROM THE AREA.
PRELIMINARY POINT TEMPS/POPS
PDT 90 54 97 61 / 0 0 0 0
ALW 93 60 98 67 / 0 0 0 0
PSC 92 58 98 60 / 0 0 0 0
YKM 90 56 98 62 / 0 0 0 0
HRI 93 56 98 64 / 0 0 0 0
ELN 88 55 95 63 / 0 0 0 0
RDM 92 53 98 54 / 0 0 0 0
LGD 94 54 99 61 / 0 0 0 0
GCD 97 56 100 59 / 0 0 0 0
DLS 97 57 99 64 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...AIR QUALITY ALERT UNTIL 5 AM PDT TUESDAY FOR WAZ024-026>030-
521>523.
OR...AIR QUALITY ALERT UNTIL 5 AM PDT TUESDAY FOR ORZ041-044-049-
050-502-503-505>511.
DISCUSSION...95
AVIATION...90
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