523
FXUS66 KPDT 051711
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1011 AM PDT FRI SEP 5 2025
UPDATED FOR AVIATION
AVIATION
18Z TAFS...VFR CONDITIONS ARE EXPECTED ACROSS THE AREAS FOR THE
MOST PART THROUGH SATURDAY, WITH A FEW CAVEATS. THERE WILL BE SOME
REDUCED VSBYS MAINLY AT YKM, BUT COULD HAVE SOME LOCAL REDUCTIONS
ELSEWHERE DUE TO SMOKE FROM REGIONAL FIRES.
OTHERWISE, LATEST RADAR HAD SOME SHRA OVER CENTRAL OREGON, AND
ADDITIONAL SHRA AND SOME TSRA ARE EXPECTED TO DEVELOP THIS
AFTERNOON MAINLY FROM 05/2200Z THROUGH 06/0100Z. THE MOST LIKELY
LOCATIONS TO SEE TSRA WOULD BE BDN AND RDM AND INCLUDED TEMPO
GROUPS AT THIS TIME.
OUTSIDE OF ANY TSRA, WINDS WILL BE 10 KTS OR LESS.
PREV DISCUSSION
/ISSUED 1046 PM PDT THU SEP 4 2025/
UPDATED AVIATION...06Z TAFS...VFR CONDITIONS WILL PERSIST THROUGH
THE FORECAST PERIOD WITH THE EXCEPTION OF YKM. YKM WILL REMAIN
MVFR WITH VSBY AT 4SM THROUGH MUCH OF THE FORECAST PERIOD.
PDT/ALW/PSC WILL ALL HAVE PERIODS OF HAZE AS WELL, HOWEVER, VSBY
WILL REMAIN 6SM. WINDS ARE MOSTLY LIGHT AND VARIABLE UNDER 6 KTS
WITH CIGS FEW/SCT 15025 KFT. BENNESE/90
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 90 61 85 / 10 20 40 30
ALW 69 91 66 86 / 10 10 30 30
PSC 64 92 63 88 / 10 10 20 20
YKM 68 93 63 86 / 10 20 30 30
HRI 66 91 63 87 / 10 20 30 30
ELN 63 91 60 82 / 10 30 30 40
RDM 53 86 50 79 / 40 40 30 40
LGD 59 88 57 84 / 10 30 40 40
GCD 59 88 55 84 / 30 40 30 30
DLS 68 89 65 84 / 20 40 40 30
PDT WATCHES/WARNINGS/ADVISORIES
OR...RED FLAG WARNING UNTIL 11 PM PDT THIS EVENING FOR ORZ696>700-704-
705.
WA...NONE.
SHORT TERM...86
LONG TERM....86
AVIATION...77
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