097
FXUS66 KPDT 151012
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
312 AM PDT TUE SEP 15 2026
KEY MESSAGES
- TEMPERATURES WILL SLOWLY WARM TO ABOVE NORMAL BY THE END OF
THE WEEK.
- SLIGHT CHANCE TO CHANCE (10-30%) OF THUNDERSTORMS OVER THE
BLUE MOUNTAINS REGION THURSDAY AND FRIDAY.
DISCUSSION
WATER VAPOR IMAGERY SHOWS A SHORTWAVE TROUGH MOVING SOUTHEAST
ALONG THE BC COAST. THIS SYSTEM WILL FACILITATE OUR NEXT CHANCES
OF RAIN, WITH A SLIGHT CHANCE (15-25%) OF SHOWERS ARRIVING TO
THE WASHINGTON CASCADES LATER THIS MORNING. THE SHORTWAVE WILL
THEN DEVELOP INTO A CLOSED LOW OVER THE PACIFIC NORTHWEST LATER
THIS AFTERNOON THROUGH TONIGHT AND PROVIDE MODEST CHANCES
(15-40%) OF PRECIPITATION ACROSS CENTRAL OREGON AND THE
SURROUNDING MOUNTAINS.
ENSEMBLE NWP GUIDANCE IS IN REASONABLY GOOD AGREEMENT REGARDING
THE TRACK OF THE LOW, BUT SOME UNCERTAINTY EXISTS IN ITS
LOCATION FOR WEDNESDAY THROUGH FRIDAY. IN GENERAL, ENSEMBLE MEAN
500-HPA HEIGHTS AND VORTICITY SHOW THE LOW RETROGRADING SLIGHTLY
ON WEDNESDAY, TRACKING FROM SOUTHWEST OREGON TO NORTHWEST
CALIFORNIA, OR JUST OFFSHORE. THE FORECAST AREA WILL REMAIN
MOSTLY DRY ON WEDNESDAY, INCREASINGLY SO THE FARTHER SOUTHWEST
THE LOW TRACKS. THE LOW IS THEN EXPECTED TO EJECT NORTHEAST
ACROSS THE PACIFIC NORTHWEST THURSDAY THROUGH FRIDAY, THOUGH
CLUSTERS OF ENSEMBLE SOLUTIONS CONTINUE TO SHOW SOME DIFFERENCES
IN TIMING AND MAGNITUDE OF THE LOW DURING THIS PERIOD. OVER
HALF OF MEMBERS ADVERTISE A SOLUTION THAT IS CONDUCIVE TO
CONVECTION THURSDAY (BLUE MOUNTAINS REGION AND PORTIONS OF
CENTRAL OREGON) AND FRIDAY (NORTHEAST BLUE MOUNTAINS). CHANCES
OF THUNDERSTORMS ARE HIGHEST ON THURSDAY (15-30%), ESPECIALLY
FOR THE NORTHEAST BLUE MOUNTAINS. CHANCES DROP TO 10-15% FOR
FRIDAY, HIGHEST OVER WALLOWA COUNTY.
ALL ENSEMBLE MEMBERS INDICATE THE LOW WILL EXIT TO THE EAST BY
SATURDAY, WITH TRANSIENT UPPER-LEVEL RIDGING REPLACING IT OVER
THE PACIFIC NORTHWEST. THIS WOULD FACILITATE ABOVE-NORMAL
TEMPERATURES AND DRY CONDITIONS AREAWIDE.
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. CIGS WILL
LOWER DURING THE DAY AS LOW PRESSURE MOVES TOWARD THE REGION BY
THE END OF THE PERIOD. THERE IS A VERY LOW (<20 PERCENT) CHANCE
OF SHRA BY THE END OF THE PERIOD AS WELL, MAINLY AT YKM, DLS,
BDN AND RDM. HOWEVER, SINCE THE CHANCES ARE SO LOW, HAVE NOT
INCLUDED IN ANY OF THE INDIVIDUAL TERMINALS AT THIS TIME. WINDS
WILL MAINLY BE 10 KTS OR LESS, THOUGH THERE IS A CHANCE 30-40
PERCENT) OF WINDS GUSTING TO AROUND 15 KTS IN THE AFTERNOON AT
BDN AND RDM FOR A COUPLE OF HOURS.
PRELIMINARY POINT TEMPS/POPS
PDT 68 44 72 47 / 0 10 0 0
ALW 70 48 75 52 / 0 10 0 0
PSC 71 46 78 48 / 10 10 0 0
YKM 66 47 74 48 / 10 10 0 0
HRI 71 46 76 47 / 0 10 0 0
ELN 60 42 70 45 / 20 10 0 0
RDM 69 39 68 37 / 0 40 10 0
LGD 71 45 74 45 / 0 10 0 0
GCD 74 45 74 45 / 0 20 10 10
DLS 73 54 80 55 / 0 10 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...NONE.
DISCUSSION...86
AVIATION...77
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