406
FXUS66 KPDT 200529
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1029 PM PDT MON OCT 19 2026
.UPDATED AVIATION DISCUSSION.
KEY MESSAGES
- RIDGING CONTINUES TO PROMOTE WARM AND DRY CONDITIONS THROUGH
THE NEXT COUPLE OF DAYS.
- WEATHER SYSTEM PUSHES THROUGH MID-WEEK, ENABLING SLIGHT
CHANCES (15-25%) OF THUNDERSTORMS ACROSS THE WALLOWAS AND
PARTS OF THE BLUE MOUNTAINS, WETTING RAINS, AND BREEZY WINDS.
- UNCERTAINTY WITH THE PATTERN THROUGH THE WEEKEND GOING INTO
EARLY NEXT WEEK.
DISCUSSION
SATELLITE SHOWS MID TO UPPER LEVEL BROKEN TO OVERCAST SKIES
ACROSS THE REGION WITH LIGHT RADAR RETURNS NOT REACHING THE
GROUND. SURROUNDING SOUNDINGS FROM SPOKANE AND MEDFORD RECORDED
MID-LEVEL DRY AIR, EVAPORATING ANY PRECIPITATION BEFORE IT HAS A
CHANCE TO REACH THE SURFACE. UPPER LEVEL RIDGING WILL CONTINUE
TO INFLUENCE THE SYNOPTIC PATTERN, ALLOWING MAX TEMPERATURES TO
CLIMB UP TO 10-15 DEGREES ABOVE SEASONAL AVERAGE ACROSS THE
REGION. CURRENT GUIDANCE SUGGESTS HIGH TEMPERATURES WILL REACH
THE UPPER 60S TO LOW 70S BY WEDNESDAY (70-80% CHANCE) AS THE
RIDGE CONTINUES TO TRAVEL EAST. WINDS IN THE SHORT TERM WITH THE
UPPER RIDGE WILL BE LIGHT IN GENERAL WITH STANDARD DIURNAL
CYCLES.
A LOW PRESSURE SYSTEM ASSOCIATED WITH A TROUGH CURRENTLY RESIDES
JUST OFF IN THE PACIFIC MOVING IN A SOUTH/SOUTH SOUTH-WEST
MOTION, WHICH WILL CONTINUE UNTIL SOMETIME LATE TUESDAY THROUGH
MID WEDNESDAY. GUIDANCE IS IN GOOD AGREEMENT THAT THE CUT-OFF
LOW WILL THEN MOVE ONSHORE INTO CALIFORNIA BRINGING WRAP AROUND
PRECIPITATION INTO THE REGION WITH POP'S UP TO 30-70% THROUGH
THURSDAY AND INTO EARLY FRIDAY. HEAVIER/GREATER CHANCES OF THAT
RANGE WILL BE MOSTLY IN THE WALLOWAS AND PARTS OF THE SOUTHERN
BLUES DOWN INTO CENTRAL OREGON. CURRENT NBM ESTIMATES ADVERTISE
UP TO A TENTH OF AN INCH OF RAIN IN THE FOOTHILLS OF THE BLUES
AND GRADUALLY INCREASES UP TO A HALF INCH WHEN YOU GET INTO THE
EASTERN MOUNTAINS (50-70% CHANCE FOR ALL QPF'S). CONFIDENCE IS
ONLY MEDIUM WITH THE WIDESPREAD OF 6-HOUR 25TH-75TH PERCENTILES
ACROSS THE AREA DUE TO THE .15-.25 INCH DIFFERENCES BETWEEN THE
QUARTILES. CONFIDENCE IS HIGH (70-90% CHANCE) WE SEE WETTING
RAINS (>.1") OVER A 24-HOUR PERIOD IN SOME LOCATIONS ALONG THE
EASTERN MOUNTAINS, GRAND RONDE VALLEY, AND PARTS OF THE JOHN DAY
BASIN THROUGH FRIDAY.
UP TO 150-200 J/KG OF CAPE WILL DEVELOP THURSDAY ACROSS WALLOWA
AND PARTS OF THE SOUTHERN BLUES BRINGING SLIGHT THUNDERSTORM
POTENTIAL (15-25% CHANCE). STORMS ARE NOT EXPECTED TO LAST LONG
AND BE MORE PULSEY WITH NO SEVERE WEATHER EXPECTED. A COLD
FRONT WILL BRING TIGHT PRESSURE GRADIENTS ACROSS THE REGION
THURSDAY AND FRIDAY, ENABLING BREEZY TO LOCALLY WINDY CONDITIONS
TO OCCUR ACROSS MOST OF THE REGION. NBM ADVERTISES 50-80%
CHANCES OF WIND GUSTS 30 MPH OR GREATER ACROSS MUCH OF THE
REGION (EXCEPT FOR CENTRAL OREGON). UPPING THE THRESHOLD TO 45
MPH OR GREATER (WIND ADVISORY CRITERIA) LOWERS THE CHANCES
EXCLUSIVE TO THE DALLES AND THE CASCADE GAPS AT 20-40%. OVERALL,
NOT TOO CONCERNED FOR WIND ADVISORIES AS OF YET, BUT WILL SEE
HOW THIS EVOLVING FORECAST CHANGES AND WILL SEE IF HIGHLIGHTS
ARE NEEDED LATER THIS WEEK.
ANOTHER SHORTWAVE IS EXPECTED TO MOVE DOWN FROM BRITISH COLUMBIA
DOWN INTO THE PACNW (70-80% CHANCE) WITH UNCERTAINTY WITH HOW
CLUSTERS HANDLE THE SHORTWAVE. IN FACT, 29% OF CLUSTERS WANT TO
BRING RIDGING OVER THE AREA WITH AREA WIDE DRY CONDITIONS BY SUNDAY.
ON THE FLIP SIDE, 54% CLOSE THE LOW AND BRING CHANCES (30-40%) OF
MODERATE TO HEAVY SNOW IN THE CASCADES. STILL A WHILE TO MONITOR BUT
THE POTENTIAL FOR SOME IMPACTS IS POSSIBLE AS WE HEAD CLOSER TO THE
WEEKEND. STAY TUNED!
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
VFR CONDITIONS CURRENTLY ACROSS ALL SITES, WHICH WILL STAY THE
COURSE THROUGH THE PERIOD. LIGHT WINDS ARE EXPECTED TO STAY
BELOW 8KTS, WITH BREAKING CLOUDS RETURNING BY EARLY EVENING. 75
PRELIMINARY POINT TEMPS/POPS
PDT 36 63 36 67 / 0 0 0 0
ALW 41 63 42 67 / 0 0 0 0
PSC 36 68 35 68 / 10 0 0 0
YKM 40 70 39 69 / 10 0 0 0
HRI 36 65 34 67 / 0 0 0 0
ELN 36 66 36 68 / 0 0 0 0
RDM 29 62 27 71 / 20 0 0 0
LGD 36 70 39 74 / 0 0 0 0
GCD 38 72 40 75 / 0 0 0 0
DLS 44 71 42 73 / 10 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...NONE.
DISCUSSION...95
AVIATION...75
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