667
FXUS66 KPDT 100526
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1026 PM PDT THU APR 9 2026
.UPDATED AVIATION DISCUSSION.
KEY MESSAGES
- RAIN AND MAINLY MOUNTAIN THUNDERSTORM CHANCES BEGIN TODAY IN
CENTRAL OREGON AND INCREASE FRIDAY AND SATURDAY.
- COOLER, MORE SEASONAL TEMPERATURES NEXT WEEK.
- ELEVATED RIVER LEVELS ON THE NACHES AND PORTIONS OF THE GRANDE
RONDE WITH CERTAIN OTHER RIVERS HAVING IN-BANKS RISES.
DISCUSSION
AN UPPER LOW OFF OF NORTHERN CALIFORNIA WILL MOVE EASTWARD AND
WEAKEN AS IT MOVES INLAND AS AN OPEN TROUGH LATER TODAY. ANOTHER
UPPER LOW WILL MOVE TOWARD NORTHERN CALIFORNIA AND MOVE INLAND
SATURDAY NIGHT OR SUNDAY MORNING. THE COMBINATION OF THESE TWO
LOWS WILL HELP KEEP A BROAD UPPER TROUGH OVER THE WESTERN STATES
AND KEEP THE WEATHER UNSETTLED THROUGH THE WEEKEND.
PRECIPITATION AND THUNDER CHANCES WILL DEVELOP MAINLY ACROSS
CENTRAL OREGON TODAY THEN BECOME MORE WIDESPREAD ON FRIDAY WITH
THE BEST (20-30 PERCENT) CHANCES OF THUNDER ACROSS CENTRAL
OREGON AND THE JOHN DAY HIGHLANDS AND RAIN CHANCES SPREADING
ACROSS MUCH OF OREGON. BY SATURDAY, RAIN CHANCES SPREAD
EVERYWHERE, WITH THUNDER SPREADING NORTH AND EASTWARD AS WELL.
THERE STILL REMAINS GOOD CAPE AND LIS BUT SOME CIN AS WELL.
THUNDERSTORMS COULD BE MORE WIDESPREAD ON SATURDAY, EVEN THOUGH
OVERALL PERCENTAGES ARE LOWER (GENERALLY <20 PERCENT). THERE
STILL ALSO REMAINS A QUESTION AS TO IF THERE WILL BE TOO MUCH
CLOUD COVER, ESPECIALLY SATURDAY TO INHIBIT WIDESPREAD
THUNDERSTORM DEVELOPMENT, AND WILL THERE BE BREAKS WHERE
CONVECTION CAN FORM.
BY SUNDAY THE WHOLE TROUGH BEGINS TO MOVE NORTH AND EASTWARD
WITH RAIN AND SOME LIMITED THUNDER CHANCES LINGERING. MONDAY
WILL SEE IMPROVING CONDITIONS AS HIGH PRESSURE BUILD IN. THE
FLOW BECOMES MORE ZONAL ON TUESDAY, AND THIS WILL USHER IN
ANOTHER SYSTEM AND ANOTHER SHOT OF RAIN BY LATER TUESDAY INTO
WEDNESDAY, WITH DRIER WEATHER RETURNING FOR THURSDAY.
THE RAIN OVER THE WEEKNIGHT WILL CAUSE SOME RIVERS TO RISE,
WITH THE NACHES AND SOME POINTS ON THE GRANDE RONDE FORECAST TO
REACH ACTION STAGE. OTHERS WILL SEE IN-BANKS RISES BUT ARE NOT
FORECAST TO REACH ACTION STAGE AT THIS TIME.
AVIATION /06Z TAFS THROUGH 06Z SATURDAY/
VFR CONDITIONS CURRENTLY ACROSS ALL SITES, WHICH WILL STAY THE
COURSE THROUGH THE PERIOD. CEILINGS WILL DECREASE TO AROUND 5KFT FOR
KRDM/KBDN BY LATE MORNING, WITH LIGHT SHOWERS INITIATING AND
PERSISTING THROUGH THE REMAINDER OF THE EVENING. THERE IS ALSO A 20-
30% CHANCE OF ISOLATED THUNDERSTORMS THROUGH THE AFTERNOON AT THESE
TERMINALS, BUT OVERALL COVERAGE AND CONFIDENCE IS LOW ENOUGH TO NOT
INCLUDE IN TAFS AT THE MOMENT. ELSEWHERE, CEILINGS WILL DROP TO
BETWEEN 8-10KFT THROUGH THE AFTERNOON AS A SLOW MOVING SYSTEM LIFTS
FROM THE SOUTH. WINDS WILL STAY LIGHT AND BELOW 10KTS AT ALL
TERMINALS. 75
PRELIMINARY POINT TEMPS/POPS
PDT 42 66 46 68 / 0 30 30 60
ALW 45 67 49 68 / 0 20 30 70
PSC 42 71 48 73 / 0 10 30 40
YKM 43 70 47 69 / 0 10 20 30
HRI 41 69 47 71 / 0 10 30 40
ELN 40 67 44 64 / 0 10 20 40
RDM 39 67 40 63 / 30 60 60 50
LGD 41 68 44 63 / 0 40 50 80
GCD 45 64 43 63 / 10 70 60 70
DLS 48 72 51 69 / 10 10 40 50
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...NONE.
DISCUSSION...77
AVIATION...75
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