441
FXUS66 KPDT 041752
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1052 AM PDT THU SEP 4 2025
AVIATION...18Z TAFS
OPTIMISTICALLY, HAVE KEPT VFR CONDITIONS AT
ALL SITES EXCEPT YKM WHICH IS FORECAST TO SEE PERSISTENT MVFR
VSBYS DUE TO SMOKE. ANTICIPATING SMOKE TO CONTINUE PUSHING SOUTH
AND EAST THROUGH THE DAY INTO FRIDAY, BUT LEFT FORECAST VSBYS AT
PDT/ALW/PSC AT 6SM DUE TO LOW CONFIDENCE (<30%) IN THE MAGNITUDE
OF VSBY REDUCTIONS.
MID- AND HIGH-LEVEL CLOUDS, AND SMOKE ALOFT, WILL PERSIST THROUGH
THE PERIOD. THE PROBABILITY OF AN ISOLATED SHOWER OR THUNDERSTORM
AT BDN/RDM THIS AFTERNOON AND EVENING IS LOW (<20%).
WINDS ARE EXPECTED TO BE MOSTLY LIGHT (10 KTS OR LESS), DIURNALLY
AND TERRAIN-DRIVEN THROUGH THE PERIOD. PLUNKETT/86
PREV DISCUSSION
/ISSUED 842 PM PDT WED SEP 3 2025/
UPDATED DISCUSSION...UPDATED THE FORECAST TO RESEMBLE THE CURRENT
RADAR SITUATION. THE THREAT FOR THUNDERSTORMS HAS PAST, HOWEVER,
CANNOT RULE OUT A SHOWER OR TWO. CURRENT RADAR SHOWS THERE TO BE A
FEW SMALL CELLS MOVING OVER THE SOUTHERN AND CENTRAL PORTIONS OF
THE REGION WITH NO LIGHTNING WITHIN THEM. CURRENT GROUND
OBSERVATIONS SHOW VERY LITTLE TO NO PRECIPITATION ASSOCIATED WITH
THEM. OTHER THAN THESE CHANGES, NO OTHER CHANGES HAVE BEEN MADE TO
THE FORECAST GOING FORWARD. EVERYTHING IS STILL ON TRACK WITH THE
RED FLAG WARNINGS IN KITTITAS AND THE EXTREME HEAT WARNING AND
HEAT ADVISORIES THAT REMAIN IN AFFECT THROUGH 8 PM THURSDAY.
BENNESE/90
PREV DISCUSSION
/ISSUED 505 PM PDT WED SEP 3 2025/
UPDATE...THE PRESENCE OF A PYROCB CLOUD ASSOCIATED WITH THE
WILDCAT FIRE IN WA695 HAS PROMPTED THE ISSUANCE OF A RED FLAG
WARNING FOR HOT, DRY, AND UNSTABLE CONDITIONS THROUGH 9 PM PDT
THURSDAY. PLUNKETT/86
PREV DISCUSSION
/ISSUED 212 PM PDT WED SEP 3 2025/
DISCUSSION...RADAR SHOWS GENERALLY CLEAR CONDITIONS, EXCEPT A
BAND OF SHOWERS NEAR DESCHUTES COUNTY THANKS TO AN UPPER LEVEL
LOW THAT MOVED FROM NORTH CALIFORNIA TO SOUTHERN OREGON. A POP-UP
OF MIXED WET/DRY THUNDERSTORMS IS POSSIBLE OVER THE NEXT SEVERAL
HOURS AS PEAK DAYTIME HEATING STARTS TO TAKE EFFECT. CAMS SHOW A
LITTLE AGGRESSION IN THE LATER PART OF THE AFTERNOON FOR >40 DBZ
PAINTBALLS, BUT WILL WAIT AND SEE IF THIS VERIFIES THE RFW.
OVERALL, A HAZY AND SILKY SETTING HAS TAKEN PLACE OVER THE CWA
THANKS TO THE ABUNDANCE OF WILDFIRE SMOKE AROUND AND IN THE AREA.
IN FACT, THE WA DEPT OF ECOLOGY WENT AHEAD AND ISSUED AIR QUALITY
ALERTS UNTIL FURTHER NOTICE FOR ALL WA COUNTIES IN THE CWA DUE TO
DECREASED AIR QUALITY LEVELS. HEAT HIGHLIGHTS CONTINUE THROUGH
TODAY AS THE UPPER RIDGE CONTINUES TO DOMINATE THE PACNW, WITH
EXPECTED TRIPLE DIGIT HIGHS IN PARTS OF THE BASIN. HIGHS WILL COOL
OFF VERY SLIGHTLY THROUGH TOMORROW WITH "MAJOR" IMPACTS BEING
LESS WIDESPREAD (BUT STILL IMPACTFUL) GOING INTO TOMORROW.
THUNDERSTORMS TOMORROW WILL NOT BE INFLUENCED BY THE UPPER LOW,
INSTEAD BE MORE DIURNALLY DRIVEN. CAMS HINTING SIGNS OF
CONVECTION FOR CENTRAL OR AND PARTS OF THE SOUTHERN BLUES AND
CASCADES. WENT AHEAD AND ADDED POP THUNDER (15-20% CHANCE) FOR
THOSE AREAS TOMORROW AFTERNOON. WASN'T TOO CONFIDENT IN ISSUING
RFW FOR PARTS OF THE OR CASCADES AND OTHER PARTS NEAR CENTRAL OR
GIVEN THE UNCERTAINTY OF THE STRENGTH OF THESE STORMS. GOING
THROUGH THE NEXT SEVERAL DAYS, WE'LL SEE AN OPPOSITE PATTERN THAN
THE DRY/HOT SET-UP WE'VE HAD THIS WEEK. THE RIDGE WILL PUSH OFF TO
THE EAST WHILE A TROUGH WILL BEGIN TO INFLUENCE THE PATTERN.
COOLER HIGHS WILL ENTER THE PICTURE BY THE WEEKEND WITH HIGHS IN
THE LOW TO MID 80S, WITH POSSIBLE SUB-80 DEGREE HIGHS BY THE
BEGINNING OF NEXT WEEK. AT THE EXPENSE, WE'LL SEE MORE WIDESPREAD
PRECIPITATION FOR MULTIPLE DAYS THAT WILL EXTEND TO MUCH OF THE
FORECAST AREA. COULD SEE SOME STORMS TURN INTO THUNDERSHOWERS OR
THUNDERSTORMS DURING THE PEAK HEATING PHASE, ESPECIALLY ACROSS THE
MOUNTAIN REGIONS. THIS WILL BRING RELIEF TO THE SMOKE AND HAZE
WE'VE WITNESSED FOR THE PAST SEVERAL DAYS. ALTHOUGH I'M NOT
CONFIDENT JUST YET (~35% CHANCE) OF IT COMPLETELY CLEARING THE AIR
BY ROUND-UP WEEK STARTING. WINDS REMAIN LIGHT UP TO 12 KNOTS,
ALBEIT WILL BE A BIT STRONGER NEXT WEEK WITH THE NEXT DISTURBANCE
PUSHING THROUGH, ESPECIALLY THE CASCADE GAPS.
PRELIMINARY POINT TEMPS/POPS
PDT 97 65 95 63 / 0 0 0 10
ALW 97 69 96 67 / 0 0 0 0
PSC 99 63 97 61 / 0 0 0 0
YKM 100 67 95 66 / 0 0 0 10
HRI 99 65 96 63 / 0 0 0 10
ELN 98 62 93 61 / 10 0 0 10
RDM 92 56 90 53 / 20 20 30 30
LGD 95 61 94 60 / 0 0 0 10
GCD 92 61 92 60 / 10 10 10 20
DLS 99 70 97 68 / 10 10 10 20
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.
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.
UPDATE...90/86
SHORT TERM...95
LONG TERM....95
AVIATION...86
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