646
FXUS66 KPDT 042339
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
439 PM PDT THU SEP 4 2025
UPDATED AVIATION DISCUSSION
AVIATION...00Z TAFS
VFR CONDITIONS PREVAIL THROUGH THE TAF
PERIOD. KRDM/KBDN WILL HAVE LIGHT SHOWERS THROUGH THIS EARLY EVENING
WITH ISOLATED TO SCATTERED THUNDERSTORMS (<30% CHANCE). HAZE/SMOKE
WILL CONTINUE TO LINGER ACROSS KPDT/KYKM/KALW/KPSC DUE TO ONGOING
NEARBY WILDFIRES. HOWEVER, NOT SIGNIFICANT ENOUGH TO IMPACT THEIR
VSBYS. DIURNALLY AND TERRAIN-DRIVEN WINDS (10KTS OR LESS) WILL
PREVAIL FOR THE OTHER SITES. FEASTER/97
PREV DISCUSSION
/ISSUED 206 PM PDT THU SEP 4 2025/
DISCUSSION
TODAY THROUGH SUNDAY, A HOT, DRY, AND UNSTABLE
PATTERN WILL GRADUALLY YIELD TO A SLIGHTLY COOLER CONVECTIVE
PATTERN AS MULTIPLE SHORTWAVES ROTATE AROUND A CLOSED LOW THAT IS
CURRENTLY CHURNING OFFSHORE IN THE PACIFIC.
RED FLAG WARNINGS HAVE BEEN ISSUED FOR PORTIONS OF CENTRAL
OREGON, VALID FRIDAY AFTERNOON THROUGH FRIDAY EVENING, FOR
THUNDERSTORMS CAPABLE OF PRODUCING ABUNDANT CLOUD-TO-GROUND
LIGHTNING. WHILE STORM MOTION WILL BE SLOW (5-15 MPH) -- AND
PWATS NEAR TO ABOVE NORMAL -- WHICH WILL LIKELY FACILITATE AT
LEAST SOME WET CORES, THE MAIN CONCERN IS ABUNDANT LIGHTNING ON
DRY FUELS. ADDITIONALLY, FIRE WEATHER WATCHES HAVE ALSO BEEN
ISSUED FOR PORTIONS OF THE EASTERN MOUNTAINS AND THE WARM SPRINGS
RESERVATION, ALSO FOR LIGHTNING.
FARTHER NORTH, ISOLATED CONVECTION IS FORECAST FOR THE WASHINGTON
CASCADES TODAY AND FRIDAY, BUT CONFIDENCE IN ABUNDANT CLOUD-TO-
GROUND LIGHTNING IS TOO LOW (<30%) TO ISSUE ANY ADDITIONAL FIRE
WEATHER HIGHLIGHTS.
SATURDAY AND SUNDAY, ADDITIONAL ROUNDS OF CONVECTION ARE FORECAST
FOR MUCH OF THE FORECAST AREA, ESPECIALLY THE CASCADES AND BLUES,
BUT ALSO PORTIONS OF THE COLUMBIA BASIN AND ADJOINING LOWER
ELEVATIONS. SOME UNCERTAINTY REMAINS WITH REGARD TO HOW MUCH
SMOKE FROM WILDFIRES WILL DAMPEN CONVECTIVE ACTIVITY, SO HAVE HELD
OFF ON ANY WATCHES OR WARNINGS FOR LIGHTNING GIVEN THE
AFOREMENTIONED UNCERTAINTY AND LONGER LEAD TIME.
MONDAY THROUGH THURSDAY, ANALYSIS OF 12Z ENSEMBLE CLUSTERS
SUGGESTS A HIGH PROBABILITY (>70%) IN A PATTERN CHANGE TO COOLER,
UNSETTLED CONDITIONS AS THE UPPER LOW SWINGS ONSHORE. WIDESPREAD
SHOWERS ARE FORECAST, WITH A SLIGHT CHANCE OF THUNDER FOR THE
MOUNTAINS (MAINLY THE BLUES). PLUNKETT/86
PRELIMINARY POINT TEMPS/POPS
PDT 65 94 64 89 / 0 0 10 20
ALW 69 97 68 91 / 0 0 0 10
PSC 62 97 62 92 / 0 0 10 10
YKM 66 96 67 92 / 0 0 10 20
HRI 64 97 64 90 / 0 0 10 20
ELN 61 94 61 91 / 0 0 10 20
RDM 57 91 54 85 / 20 40 40 40
LGD 60 94 60 89 / 0 10 10 30
GCD 60 93 60 86 / 20 20 30 40
DLS 69 97 68 89 / 10 10 20 40
PDT WATCHES/WARNINGS/ADVISORIES
OR...EXTREME HEAT WARNING UNTIL 8 PM PDT THIS EVENING FOR ORZ041-044-
507-508-510.
HEAT ADVISORY UNTIL 8 PM PDT THIS EVENING FOR ORZ049-050-502-505.
FIRE WEATHER WATCH FROM FRIDAY AFTERNOON THROUGH FRIDAY EVENING
FOR ORZ696>699-703.
RED FLAG WARNING FROM 1 PM TO 11 PM PDT FRIDAY FOR ORZ700-704-
705.
WA...EXTREME HEAT WARNING UNTIL 8 PM PDT THIS EVENING FOR WAZ024-
026>029-521.
HEAT ADVISORY UNTIL 8 PM PDT THIS EVENING FOR WAZ030-523.
RED FLAG WARNING UNTIL 9 PM PDT THIS EVENING FOR WAZ695.
SHORT TERM...86
LONG TERM....86
AVIATION...97
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