666
FXUS66 KPDT 210525
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1025 PM PDT MON OCT 20 2025
.UPDATED AVIATION.
AVIATION...06Z TAFS
VFR CONDITIONS CONTINUE THROUGH THE NIGHT
AT EVERY SITE. WE'VE HAD SOME LIGHT SHOWERS POP-UP NEAR THE
KITTITAS VALLEY/YAKIMA REGION AND REPORTED LIGHT PRECIPITATION
FALLING EARLIER NEAR THAT REGION. RAIN SHOWERS WILL CONTINUE TO
DISSIPATE AS WE GO THROUGH THE NIGHT AS THE MID-LEVEL CLOUD DECK
CONTINUES TO PUSH OUT OF THE AREA. WINDS WILL CONTINUE TO BE LIGHT
AND VARIABLE AT <12 KNOTS THROUGH THE 24-HOUR PERIOD.
PREV DISCUSSION... /ISSUED 233 PM PDT MON OCT 20 2025/
DISCUSSION
KEY POINTS
1. DRY CONDITIONS EXPECTED THROUGH THURSDAY WITH CASCADE SHOWERS
2. BREEZY WINDS THROUGH THE GRANDE RONDE VALLEY TONIGHT THROUGH
WEDNESDAY MORNING
3. WIDESPREAD PRECIPITATION AND LOCALLY BREEZY CONDITIONS RETURN
OVER THE WEEKEND
TODAY THROUGH THURSDAY NIGHT...CURRENT SATELLITE SHOWS THE AREA TO
BE MOSTLY SUNNY WITH CLOUDS ONLY LINGERING OVER THE CRESTS OF THE
CASCADES OF WA AND ALONG THE SIMCOE HIGHLANDS OF KLICKITAT COUNTY.
GROUND OBSERVATIONS DO SHOW A FEW LOCALIZED LOCATIONS ALONG THE
FOOTHILLS OF THE BLUES AS WELL AS AROUND THE TRI-CITIES STILL SEEING
GUSTS TO 20 MPH WHILE ELSEWHERE WINDS HAVE CONTINUED TO DECREASE.
MODELS ARE IN FIRM AGREEMENT WITH THE UPPER LEVEL RIDGE BUILDING IN
OVER THE REGION THIS AFTERNOON. DRY CONDITIONS WILL PERSIST THROUGH
THURSDAY WITH THE MAJORITY OF THE REGION SEEING LIGHT WINDS. MODELS
ARE SHOWING A SURFACE PRESSURE GRADIENT FORMING ACROSS THE BLUES
WHICH WILL RESULT IN GUSTY WINDS THROUGH THE GRANDE RONDE VALLEY
LATER THIS AFTERNOON AND SHOWS IT PERSISTING THROUGH WEDNESDAY
MORNING. MODELS ARE IN GOOD AGREEMENT WITH THE PRESSURE GRADIENT SET
UP OVER THE BLUES AND ENSEMBLES ARE SHOWING 50-80% PROBABILITIES OF
THE VALLEY SEEING GUSTS OF 25-30 MPH.
WEDNESDAY MODELS SHOW A WEAK SHORTWAVE RIPPLING ACROSS THE REGION
BRINGING A CHANCE (20-30%) OF SHOWERS TO THE EASTERN SLOPES OF THE
CASCADES AND A 40-60% CHANCE ALONG THE CRESTS. NBM ACCUMULATIONS ARE
0.01 TO 0.05 INCHES BETWEEN 5 AM TO 5 PM WEDNESDAY WHILE THE
REMAINDER OF THE REGION WILL REMAIN DRY. WINDS THROUGH THE LADD PILE
CANYON AND GRANDE RONDE VALLEY WILL ALSO DECREASE AS THE SHORTWAVE
MOVES ACROSS. ZONAL FLOW WILL THEN DOMINATE THE REGION ALLOWING FOR
LIGHT WINDS TO RETURN THROUGH THURSDAY.
FRIDAY THROUGH THE WEEKEND...MODELS SHOW A DEEP UPPER LEVEL TROUGH
OFF THE COAST OF CANADA WITH A STRONGER COLD FRONT AHEAD OF IT THAT
WILL PASS OVER THE REGION THIS WEEKEND. MODELS ARE IN RELATIVELY
FIRM AGREEMENT WITH THE INCOMING SYSTEM WHICH ALLOWS CONFIDENCE TO
BE ON THE HIGHER END (70-80%). MODELS ALSO SHOW THIS SYSTEM TO BRING
WITH IT A DEEP PUSH OF COLDER AIR AS WELL AS MOISTURE. NBM SHOWS
SNOW LEVELS TO DROP TO 4200-5200 FEET SATURDAY, AND 3500-4000 FEET
ON SUNDAY. LIGHT TO MODERATE SNOWFALL IS LIKELY IN THE MOUNTAINS,
WITH AN 70-90% CHANCE OF 6 INCHES OR GREATER OF SNOW ACROSS SANTIAM
AND WHITE PASSES. HOWEVER, ONLY A 30-50% CHANCE IN FOR 3 INCHES
ALONG SNOQUALMIE PASS. THERE IS ALSO A 60-80% CHANCE OF 6 INCHES OR
GREATER FROM THE AREAS AROUND AND BETWEEN SKI BLUEWOOD AND TOLLGATE.
SOME HIGHER ELEVATED AREAS ON THE PERIPHERY OF BEND COULD SEE THEIR
FIRST SNOWFALL OF THE YEAR, THOUGH CONFIDENCE ON ANYTHING GREATER
THAN AN INCH IS (15-25%). 90
PRELIMINARY POINT TEMPS/POPS
PDT 37 65 37 62 / 0 0 0 0
ALW 42 64 41 62 / 0 0 0 0
PSC 36 63 33 61 / 0 0 0 0
YKM 36 62 36 62 / 20 0 0 0
HRI 37 64 36 62 / 0 0 0 0
ELN 33 61 33 60 / 20 0 0 0
RDM 30 70 33 70 / 0 0 0 0
LGD 35 64 39 67 / 0 0 0 0
GCD 34 68 37 71 / 0 0 0 0
DLS 42 68 42 66 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
SHORT TERM...90
LONG TERM....90
AVIATION...95
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