629
FXUS66 KPDT 270539
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1039 PM PDT TUE MAY 26 2026
KEY MESSAGES
- SHOWER AND THUNDERSTORM CHANCES PEAK THURSDAY BUT CONTINUE
THROUGH FRIDAY.
- BREEZY TO WINDY ON FRIDAY.
- DRIER FOR THE WEEKEND ONWARD.
DISCUSSION
AN UPPER LOW AND TROUGH OVER THE PACIFIC NORTHWEST WAS MOVING
SOUTHWARD INTO CALIFORNIA AND NEVADA.
THE MAIN LOW WILL BE SOUTH OF THE REGION ON WEDNESDAY, BUT THE
BROADER CYCLONIC FLOW WILL REMAIN OVER THE REGION ON WEDNESDAY,
AS WEAK RIDGING TRIES TO BUILD OVER THE AREA. WHILE MOST OF THE
REGION WILL REMAIN DRY, THERE COULD BE SOME SHOWERS AND
THUNDERSTORMS, MAINLY OVER THE MOUNTAINS.
THE UPPER LOW WILL BEGIN TO MOVE NORTHEASTWARD THURSDAY INTO
FRIDAY AND DECENT SHORTWAVE ENERGY WILL MOVE ACROSS THE ENERGY
ON THURSDAY. THIS ENERGY, COUPLED WITH INSTABILITY FROM THE LOW
WILL BRING THUNDERSTORM CHANCES. THE STORM PREDICTION CENTER HAS
PLACED MUCH OF OUR AREA IN MARGINAL RISK FOR SEVERE THUNDERSTORMS
ON THURSDAY. CONVECTIVE POTENTIAL WILL HAVE TO BE MONITORED ON
FRIDAY AS WELL. THURSDAY WILL ALSO BE QUITE WARM WITH HIGH
TEMPERATURES IN THE LOWER 90S ACROSS THE COLUMBIA BASIN AND
YAKIMA VALLEYS AND MID TO UPPER 80S ACROSS MUCH OF THE LOWER
ELEVATION AREAS. FRIDAY'S HIGH TEMPERATURES WILL BE 10 TO 15
DEGREES COOLER, ON AVERAGE THAN ON THURSDAY.
ON THURSDAY, CAPE VALUES ARE OVER 2000 J/KG AND LI VALUES ARE
LOWER THAN -3 DEGREES CELSIUS IN AREAS. HOWEVER, THERE IS ALSO
SOME CONVECTIVE INHIBITION AND ULTIMATELY TILL IT BE TOO CLOUDY
IN AREAS REMAINS TO BE SEEN. ECMWF EFI PUTS CAPE VALUES IN THE
80TH TO 90TH PERCENTILE.
ADDITIONALLY, ON FRIDAY, THERE WILL BE AN AREA OF GUSTY WINDS
ACROSS THE KITTITAS VALLEY, YAKIMA VALLEY, COLUMBIA BASIN,
CASCADE GAPS AND FOOTHILLS OF THE BLUE MOUNTAINS. IT IS POSSIBLE
THAT WIND HEADLINES MAY BE NEEDED FOR A PORTIONS OF THIS REGION
AS WELL.
FINALLY, IT LOOKS LIKE THERE WILL BE MORE ZONAL FLOW MOVING IN
FOR THE WEEKEND BRINGING DRIER WEATHER. A WEAK UPPER LOW MOVES
THROUGH SUNDAY NIGHT, BUT AT THIS TIME, IT APPEARS TO BE DRY,
BUT WILL NEED TO SEE IF IT REMAINS THAT WAY.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
VFR CONDITIONS ARE FORECAST AT ALL SITES OVER THE NEXT 24 HOURS,
THOUGH RDM/BDN MAY SEE MVFR CIGS OVERNIGHT INTO WEDNESDAY
MORNING (20-50 PERCENT CONFIDENCE). THE 00Z HREF AND OTHER CAMS
POINT TO A 20-50 PERCENT CHANCE OF THUNDERSTORMS LATE AFTERNOON
AND EVENING AT RDM/BDN, AND A LOWER CHANCE (10 PERCENT) AT
PDT/ALW. WINDS OF 10 KTS OR LESS ARE FORECAST EXCEPT AT RDM/BDN
WHERE 12-17 KTS WITH GUSTS OF 20-30 KTS ARE FORECAST BY MID-
MORNING THROUGH AFTERNOON. THUNDERSTORMS WILL BE CAPABLE OF
PRODUCING STRONG, GUSTY OUTFLOW WINDS.
PRELIMINARY POINT TEMPS/POPS
PDT 45 79 51 86 / 30 0 10 20
ALW 49 81 57 87 / 10 0 10 20
PSC 47 85 55 93 / 10 0 0 10
YKM 49 87 57 93 / 10 0 0 10
HRI 46 82 54 89 / 20 0 0 10
ELN 47 82 55 89 / 0 0 0 10
RDM 38 78 45 79 / 60 0 50 90
LGD 45 79 49 86 / 50 20 20 40
GCD 39 79 45 81 / 90 20 50 80
DLS 52 86 59 90 / 10 0 0 20
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...NONE.
DISCUSSION...77
AVIATION...86
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page