238
FXUS66 KPDT 091020
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
220 AM PST MON FEB 9 2026
DISCUSSION
SATELLITE AND RADAR IMAGERY TONIGHT SHOW AN UPPER
SHORTWAVE MOVING INTO THE PACNW AFTER AN EARLIER STALLED
FRONTAL BOUNDARY AND IT'S ASSOCIATED SURFACE LOW HAVE EXITED
THE REGION. WIDESPREAD RAIN/HIGH MOUNTAIN SNOW HAS NOW BECOME
MOSTLY LIGHT MOUNTAIN SNOW SHOWERS, WITH PATCHY LOW TO MID LEVEL
CLOUD COVER ACROSS THE LOWER ELEVATIONS.
TODAY: THE AFOREMENTIONED SHORTWAVE WILL CONTINUE TO BRING LIGHT
TO MODERATE SNOW ACROSS THE CASCADES AND EASTERN MOUNTAINS WITH
A FEW SCATTERED LIGHT RAIN SHOWERS ACROSS PORTIONS OF THE
COLUMBIA BASIN AND BLUE MOUNTAIN FOOTHILLS. BY THIS EVENING THE
SHORTWAVE WILL HAVE MOVED EAST OF THE REGION, TAKING WITH IT THE
PRECIPITATION CHANCES ACROSS OUR MOUNTAIN ZONES. THROUGH THIS
EVENING, THERE IS MOD-HIGH CONFIDENCE (65-85%) IN AN ADDITIONAL
1 TO 4 INCHES ACROSS THE CASCADE CREST, NORTHERN BLUES, AND THE
EAGLE CAPS, WHILE CONFIDENCE IS LOW (15-20%) IN GREATER THAN 4
INCHES OF ADDITIONAL ACCUMULATIONS IN THE NORTHERN BLUES.
OTHERWISE, BREEZY WINDS WITH GUSTS MAINLY 20-30 MPH WILL DEVELOP
ACROSS WIND PRONE AREAS IN THE LOWER ELEVATION ZONES AND
EXPOSED RIDGES LATE THIS MORNING INTO THE AFTERNOON HOURS.
TUESDAY THROUGH THURSDAY: DETERMINISTIC AND ENSEMBLE GUIDANCE
HAS COME INTO BETTER AGREEMENT OF UPPER LEVEL RIDGING BUILDING
TO THE NORTH OF THE FORECAST AREA LATE TODAY INTO THE FIRST
HALF OF TUESDAY. THIS WILL RESULT IN MOSTLY DRY AND MILD
CONDITIONS TO START OFF THE MID WEEK. A WEAK INVERSION
DEVELOPING TUESDAY MORNING MAY RESULT IN SPOTTY LOW
STRATUS/PATCHY FOG DEVELOPING ACROSS THE COLUMBIA BASIN AND
ADJACENT VALLEYS. BY LATE TUESDAY, THE RIDGE WILL PUSH EAST AS A
TROUGH WITH TWO DEFINED LOWS DEVELOPS OFFSHORE. ONE OF THE LOWS
WILL MOVE INLAND AND BECOME AN OPEN WAVE ACROSS NORTHERN CA AND
SOUTHERN OR LATE TUESDAY NIGHT THROUGH WEDNESDAY. SHORTWAVE
IMPULSES SWINGING OUT OF THE LOW DURING THIS PERIOD WILL BRING
LIGHT SNOW TO PORTIONS OF CENTRAL OR, OCHOCO-JOHN DAY HIGHLANDS,
AND THE STRAWBERRYS/ELKHORNS/WALLOWAS.
BY LATE WEDNESDAY, THE TROUGH AXIS WILL EXIT THE REGION,
ALLOWING A TRANSIENT RIDGE TO MOVE OVER THE PACNW WITH DRY
CONDITIONS PREVAILING THROUGH THURSDAY.
FRIDAY THROUGH SUNDAY: BY EARLY FRIDAY, ENSEMBLE CLUSTER
SOLUTIONS SHOW A TROUGH DROPPING OUT OF THE GULF OF ALASKA AND
SETTING UP OFFSHORE THE PACNW. OVER THE WEEKEND, THE TROUGH WILL
SWING INLAND WITH INCREASING PRECIPITATION CHANCES ACROSS THE
FORECAST AREA. WHILE CONFIDENCE IS MOD-HIGH(65-80%) IN THE
TROUGHING, ENSEMBLE CLUSTER SOLUTIONS SHOW UNCERTAINTY IN THE
POSITION AND TIMING OF THE TROUGH PASSAGE EARLY SATURDAY THROUGH
SUNDAY. WHILE THE SIMPLE MAJORITY (~60%) OF ENSEMBLE CLUSTER
SOLUTIONS FAVOR LIGHT TO LOCALLY MODERATE SNOW IN THE MOUNTAINS,
THE REMAINING SOLUTIONS (~40%) FAVOR MODERATE TO HEAVY SNOW
ACCUMULATIONS IN THE CASCADES AND NORTHERN BLUES THROUGHOUT THE
WEEKEND. IN THE LOWER ELEVATIONS, THERE IS AT LEAST MODERATE
CONFIDENCE (40-60%) OF LIGHT RAIN DURING THE DAYLIGHT HOURS,
WITH LOWER CONFIDENCE (20-35%) IN LIGHT SNOW OR A RAIN/SNOW MIX
DEVELOPING IN THE OVERNIGHT HOURS THROUGH THE WEEKEND.
LAWHORN/82
AVIATION /06Z TAFS THROUGH 06Z TUESDAY/
RAIN CHANCES WILL
DWINDLE FROM WEST TO EAST LATE TONIGHT AND EARLY MONDAY MORNING.
IN THE MEANTIME, LOCATIONS LIKE PDT AND ALW WILL STILL BE PRONE
TO SOME LOWER CEILINGS, IN THE IFR AND LOWER RANGE. EXPECT
VLIFR CEILINGS AT ALW FOR AT LEAST A FEW MORE HOURS OVERNIGHT
UNTIL THE RAIN ENDS, WHICH COULD BE AROUND 9Z BASE ON HREF
(ENSEMBLE TRENDS). TERMINALS FARTHER WEST LIKE RDM BDN AND YKM
HAVE SEEN MARKED IMPROVEMENT TO THE CEILINGS, AND WILL REMAIN
VFR FOR THE BALANCE OF THE TAF PERIOD.
PRELIMINARY POINT TEMPS/POPS
PDT 30 46 30 42 / 0 0 10 10
ALW 32 47 33 42 / 0 0 10 10
PSC 30 50 31 49 / 0 0 0 0
YKM 28 46 28 48 / 0 0 0 0
HRI 29 48 31 46 / 0 0 0 0
ELN 27 42 27 45 / 0 0 0 0
RDM 23 46 25 42 / 0 0 10 10
LGD 26 46 28 45 / 0 0 20 30
GCD 26 46 28 44 / 0 0 30 30
DLS 34 48 33 50 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...NONE.
DISCUSSION...82
AVIATION...71
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