506
FXUS66 KPDT 130521
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1021 PM PDT WED AUG 12 2026
KEY MESSAGES
- NEAR-SEASONAL TEMPERATURES THROUGH THE WEEK.
- TRANSITION TO A CONVECTIVE WEATHER PATTERN TODAY WITH DAILY
SHOWER AND THUNDERSTORM CHANCES INTO NEXT WEEK, MAINLY FOR THE
MOUNTAINS.
- CRITICAL FIRE WEATHER DUE TO LIGHTNING RISK THURSDAY AFTERNOON
DISCUSSION
THE REGION IS TRANSITIONING INTO A CONVECTIVE PATTERN WHICH
SHOULD LINGER INTO THE EARLY WEEKEND BRINGING POTENTIAL EACH
AFTERNOON AND EVENING OF SHOWER AND THUNDERSTORMS WITH POSSIBLE
FIRE WEATHER IMPACTS DUE TO LIGHTNING IF IT IS ABUNDANT ENOUGH.
CONFIDENCE FOR MEASURABLE PRECIPITATION IS NOT HIGH (IN THE 15
TO 25% RANGE) THURSDAY AFTERNOON ACROSS THE JOHN DAY
HIGHLANDS/BASIN AND SOUTHERN BLUE MOUNTAINS HOWEVER THE DROUGHT
WITH HIGH ERCS HAVE LEANED US TOWARD THE RED FLAG AS NBM
MEMBERS AREA TRENDING AROUND 0.1 FLASHES /SQ MILE /5 MINS ACROSS
THESE ZONES FROM MID AFTERNOON AND ACROSS THE OVERNIGHT HOURS
INTO FRIDAY MORNING. HRRR SMOKE MODELS SHOW A SOUTHWARD PUSH OF
VERTICALLY INTEGRATED SMOKE AS SHOWERS AND THUNDERSTORMS CAN
CREATE OUTFLOW WINDS ACROSS NORTHERN WA AND THE UPPER COLUMBIA
BASIN OVERNIGHT AND EARLY THURSDAY. TEMPERATURES CONTINUE TO
REMAIN LARGELY UNCHAINED BY THE PATTERN WITH UPPER 80S AND
ACROSS THE COLUMBIA BASIN AND COOLER LOW 80S INTO THE FOOTHILLS
AND MOUNTAIN ZONES, WARMING BACK INTO THE 90S ACROSS THE
COLUMBIA BASIN BY SUNDAY.
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
VFR CONDITIONS PREVAIL WITH MORE ELEVATED SMOKE IN SOME AREAS.
COUPLE OF TAF SITES ARE ON THE BORDERLINE WITH VISIBILITIES DOWN
TO 6 MILES. MAY SEE SOME MVFR CONDITIONS DEVELOP BUT NOT IN A
PRO-LONG WAY. MAY SEE SOME SMOKE SETTLE DOWN TO THE SURFACE
OVERNIGHT, BUT CHANCES OF THAT HAPPENING ARE SMALL AT 5 TO 15
PERCENT. NO BREEZY WINDS ANTICIPATED WITH MOST SUSTAINED WINDS
AT LESS THAN 12 KNOTS WITH MOST GUSTS NOT EXCEEDING 20 KNOTS.
FIRE WEATHER
RED FLAG WARNINGS WERE ISSUED FOR SEVERAL OREGON FIRE ZONES AS
MONSOONAL MOISTURE INTERACTS WITH WEAK UPPER VORTICITY IN THE
MEAN TROUGH FROM THE OREGON CASCADES AND EASTWARD THURSDAY
AFTERNOON/EVENING INTO HE JOHN DAY BASIN AND SOUTHERN BLUE
MOUNTAINS, EVEN BEYOND MIDNIGHT. THE SEASONAL DRY PERIOD WITH
HIGH ERCS HAVE TIPPED US TOWARD THE RED FLAG AS NBM MEMBERS ARE
TRENDING AROUND 0.1 FLASHES /SQ MILE /5 MINS ACROSS THESE ZONES
FROM MID AFTERNOON AND ACROSS THE OVERNIGHT HOURS INTO FRIDAY
MORNING AND ANY GC CAN CREATE NEW STARTS. ANY CONVECTION BEYOND
THURSDAY WILL BE EVALUATED AGAINST ANY WETTING RAIN CHANCES,
WHICH WHILE ARE NOT HIGH, ARE QUITE VARIABLE AND AT 10 TO 70% ON
A 24 HR BASIS HIGHEST IN THE EASTERN OREGON ZONES.
PRELIMINARY POINT TEMPS/POPS
PDT 52 85 54 87 / 0 0 0 0
ALW 58 87 59 88 / 0 0 0 0
PSC 57 89 58 90 / 0 0 0 0
YKM 58 88 61 88 / 20 0 10 10
HRI 55 88 59 90 / 0 0 0 0
ELN 55 83 57 82 / 40 10 20 30
RDM 44 84 49 85 / 0 0 10 10
LGD 53 86 55 86 / 0 0 30 30
GCD 52 87 54 86 / 0 10 60 40
DLS 60 90 63 91 / 0 0 0 10
PDT WATCHES/WARNINGS/ADVISORIES
WA...AIR QUALITY ALERT UNTIL 3 PM PDT FRIDAY FOR WAZ026>030-521>523.
OR...AIR QUALITY ALERT UNTIL 3 PM PDT FRIDAY FOR ORZ041-049-050-502-
503-505-506-509>511.
RED FLAG WARNING FROM 1 PM THURSDAY TO 5 AM PDT FRIDAY FOR
ORZ696>699.
RED FLAG WARNING FROM 1 PM TO 9 PM PDT THURSDAY FOR ORZ700-705.
DISCUSSION...86
AVIATION...95
FIRE WEATHER...71
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