336
FXUS66 KPDT 282039
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
139 PM PDT SAT MAR 28 2026
KEY MESSAGES
- DRY CONDITIONS THROUGH SUNDAY MORNING
- A RETURN OF ACTIVE WEATHER LATE SUNDAY AFTERNOON INTO MONDAY
WITH LIGHT PRECIPITATION IN THE MOUNTAINS
- MORE WIDESPREAD PRECIPITATION CHANCES, BREEZY WINDS, AND
COOLER CONDITIONS WEDNESDAY THROUGH THURSDAY
DISCUSSION
AFTERNOONS BECOME BREEZY TODAY AND A LITTLE MORE WINDY IN A FEW
SPOTS ON SUNDAY. THIS IS FOCUSED ACROSS THE HIGHER TERRAIN AND
MOUNTAIN ZONES ABOVE 2500-3000 FEET, SUCH AS THE SIMCOE AND
JOHNDAY/OCHOCO HIGHLANDS AND KITTITAS/YAKIMA VALLEYS AND IN THE
3 TO 7 PM WINDOW. SUNDAY NIGHT, A WEAK ATMOSPHERIC RIVER WILL
INFLUENCE THE INTERIOR NORTHWEST WITH A BROAD 200-300 KG/MS IVT,
AND A MAX OF ABOUT 18 TO 22 MM IVW INTO THE LOWER COLUMBIA
BASIN. THIS APPEARS MAINLY A MOUNTAIN AND HIGHLANDS EPISODE
AS SNOW LEVELS CRASH BEHIND THE COLD FRONT AS THE PRECIPITATION
PROBABILITY RAMPS DOWNWARD ON MONDAY. DURING THE TIME FRAME OF
EXPECTED PEAK POPS, THE SNOW LEVELS ARE EXPECTED TO RANGE FROM
AROUND 3000-3500 FT AGL ACROSS THE WA CASCADES AND AROUND
4500-6000 FT AGL OVER THE NORTHERN BLUE MOUNTAINS. LIMITED
WINTER WEATHER IMPACTS IN PART SUE TO WARM ROAD TEMPS (CURRENTLY
IN THE 40-60 DEGREE SURFACE TEMPS EVEN HOURS BEFORE PEAK
HEATING TODAY).
MONDAY AND TUESDAY APPEAR SIMILAR IN TERMS OF WINDS AND WIND
GUSTS ACROSS THE FORECAST AREA WITH WINDS IN THE 10 TO 15 MPH
RANGE FOR GUSTS IN THE LOWLANDS AND HIGHER GUSTS RANGING FROM 15
TO 30 MPH INTO HIGHER TERRAIN. A STRONGER AR IS FORECAST BY THE
ENSEMBLES AND EC/GFS CONTROL RUNS TO DEVELOP WEDNESDAY
(EXTENDING THROUGH THURSDAY) WITH MORE MEANINGFUL IMPACTS IN
TERMS SNOW FOR THE MOUNTAIN ZONES AND AND WINDY CONDITIONS OVER
A WIDER AREA. THE WWRF (GFS/EC) 9KM FREEZING LEVEL PLAN VIEW
SHOWS THE COLD FRONT MOVING ACROSS THE REGION BY WEDNESDAY. NBM
ENSEMBLE MEAN AT THIS TIME WOULD HAVE THE CRESTS OF THE
WASHINGTON AND OREGON CASCADES RECEIVE AROUND 1 FOOT ON AVERAGE
OF SNOWFALL WITH A COUPLE OF FEET UP ON THE CONE TOPS.
AS FAR AS PASS LEVEL IMPACTS, THE WSSI-P GIVES A 50 TO 70%
CHANCES FOR MINOR IMPACTS BASED ON SNOWFALL ALONE, AS THE
HIGHEST SNOW AMOUNTS FROM THE OF THE NBM MEAN ALONG I-90 IS 5 TO
7 INCHES LOCALLY. WHAT DOES FALL WILL BE A HEAVY WET, LOW SLR
SNOW WITH HIGHER PROBABILITIES IMPACT FROM SNOW LOAD THAN SNOW
AMOUNTS.
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
LIMITED AVIATION CONCERNS THE NEXT 24-HRS WITH VFR PREVAILING
AREA-WIDE. LATEST SATELLITE SHOWS MOUNTAIN WAVE CLOUDS LEE OF
THE CASCADES AND PASSING HIGH CLOUDS. A MODEST CROSS-CASCADE
PRESSURE DIFFERENCE WILL SHARPEN TODAY IN TANDEM WITH UPTICK
LOW-LEVEL FLOW TO SUPPORT GUSTS 20-25 KTS ACROSS TERMINALS,
EXCEPT LIGHTER BREEZES AT KPSC. HIGH CHANCES (70%+) FOR
HIGHEST/PEAK DAILY GUSTS REACHING 26 KTS OR MORE AT KDLS AND IN
THE EASTERN GORGE. WINDS WILL LESSEN THIS EVENING OVER 01-04
UTC. WINDS OVERNIGHT WILL BE LIGHT AND GENERALLY 4-8 KTS WITH
LIGHT/VARIABLE IN THE CENTRAL OR TERMINALS. OTHERWISE, INCREASED
CLOUDINESS, HIGH-END VFR (7 KFT OR GREATER) LATE TONIGHT/EARLY
TOMORROW AREA-WIDE.
PRELIMINARY POINT TEMPS/POPS
PDT 37 54 31 50 / 0 20 30 10
ALW 41 54 34 50 / 0 40 50 10
PSC 39 59 34 56 / 0 20 10 0
YKM 35 57 28 53 / 0 10 0 0
HRI 39 57 32 54 / 0 20 10 0
ELN 33 50 26 48 / 0 10 10 0
RDM 32 57 24 51 / 0 10 0 10
LGD 35 57 31 47 / 0 30 70 20
GCD 36 63 31 48 / 0 10 40 30
DLS 40 56 33 57 / 0 30 10 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...NONE.
DISCUSSION...71
AVIATION...82
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