644
FXUS66 KPDT 130004
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
504 PM PDT THU MAR 12 2026
KEY MESSAGES
1. HEAVY SNOW THURSDAY NIGHT INTO FRIDAY MORNING FOR THE EAST
SLOPES OF THE WA CASCADES. WINTER STORM WARNING REMAINS IN
EFFECT UNTIL 5 AM PDT SATURDAY
2. HEAVY SNOW FOR THE NORTHERN BLUE MOUNTAINS
WINTER STORM WARNING REMAINS IN EFFECT UNTIL 5 PM PDT FRIDAY
ABOVE 4000 FEET
3. BREEZY WINDS WILL CONTINUE OVER THE WEEKEND
DISCUSSION
CURRENT RADAR AND SATELLITE SHOW THE SIGNIFICANT RAIN SHADOWING
ALONG THE OR CASCADES KEEPING CENTRAL AND NORTH CENTRAL OR DRY.
HOWEVER, THE WA CASCADES ARE SEEING RETURNS AS THE ATMOSPHERIC RIVER
AND UPPER LEVEL COLD FRONT CONTINUING TO PUSH IN FROM THE WEST-
NORTHWEST. RADAR ALSO SHOWS RETURNS OVER THE NORTHERN BLUE MOUNTAINS
AS THE AR CONTINUES TO PUSH ACROSS THE WA PORTION OF THE REGION.
CW3E SHOWS FIRM AGREEMENT THAT THE AXIS OF THE AR WILL CONTINUE TO
TRAVERSE ACROSS THE REGION THROUGH FRIDAY NIGHT BEFORE ESSENTIALLY
DYING OUT.
AN AR WILL CONTINUE TO PUSH IVT VALUES OF 250-500 KG/M/S INTO THE
REGION THROUGH FRIDAY, RESULTING IN PERSISTENT MODERATE TO LOCALLY
HEAVY PRECIPITATION RATES ACROSS THE CASCADE CREST AND NORTHERN
BLUES. SNOW LEVELS HAVE HIT THE PEAK AND NBM SHOWS SNOW LEVELS TO
BEGIN TO DECREASE THROUGH THE REST OF THE DAY. GROUND OBSERVATIONS
SHOW A CLEAR LINE OF TEMPERATURE DIFFERENCE AS THE COLD FRONT BEGINS
TO ALREADY PUSH OVER THE CASCADES. THIS COLD AIR WILL CONTINUE TO
BRING SNOW LEVELS DOWN AND TURN THE PRECIPITATION FROM A WINTERY MIX
TO SNOW. NBM RAW ENSEMBLES SHOW 70-90% PROBABILITIES THAT ANOTHER 1
TO 2 FEET OF SNOW WILL ACCUMULATE OVER THE NEXT 24 TO 48 HOURS OVER
THE WA CASCADES.
CURRENT WEB CAMS ALONG THE BLUES SHOW THERE TO BE RAIN FALLING
CURRENTLY ALONG THE I-84 CORRIDOR BUT SNOW FALLING AT THE HIGHER
ELEVATIONS LIKE TOLLGATE. GROUND TEMPERATURES ALONG THE I-84
CORRIDOR ARE STILL ABOVE FREEZING BUT ARE EXPECTED TO CONTINUE TO
DECREASE ONCE THE COLD FRONT PASSES LATER THIS EVENING. NBM SHOWS
SNOW LEVELS ALONG THE BLUES TO REACH BELOW 4000 FEET. NBM RAW
ENSEMBLES SHOW 60-80% PROBABILITIES OF SEEING OVER 6 INCHES OF SNOW
ACCUMULATIONS THROUGH FRIDAY MORNING.
WINDS WILL ALSO REMAIN ELEVATED THROUGH THE WEEKEND AS ZONAL FLOW
ALOFT TAKES OVER. SUSTAINED WEST WINDS OF 10-15 MPH ARE EXPECTED
WITH 35 MPH GUSTS. THERE WILL BE LOCALIZED AREAS THAT WILL SEE
GUSTS TO 35 MPH, BUT THOSE ARE MAINLY ALONG THE RIDGETOPS AND SOME
HIGHER ELEVATIONS SUCH AS THE SIMCOE HIGHLANDS OF KLICKITAT AND THE
OCHOCO-JOHN DAY HIGHLANDS. CONFIDENCE IN THE WINDS REMAINING THROUGH
THE WEEKEND IS HIGH (70-90% CONFIDENCE).
AFTER THE WEEKEND, AR CW3E ENSEMBLES ARE IN RELATIVELY FIRM
AGREEMENT THAT THE LEADING EDGE OF AN UPPER LEVEL RIDGE WILL
TRAVERSE INTO THE PACNW. THIS WILL BRING WARMING CONDITIONS TO THE
REGION AND INCREASE SNOW LEVELS DRASTICALLY. CW3E ALSO SHOWS FIRM
ENSEMBLES AGREEMENT THAT ANOTHER, BUT WEAKER, AR WILL ROAM AROUND
THE AXIS OF THE RIDGE BRINGING MORE PRECIPITATION. PRECIPITATION
WILL BEGIN AS RAIN/SNOW BEFORE TRANSITIONING TO MOSTLY RAIN. THIS
RAIN ON SNOW PLUS WARMING TEMPERATURES WILL BRING RISES TO SOME AREA
RIVERS. FOR MORE INFORMATION SEE THE HYDROLOGIC OUTLOOK.
AVIATION /00Z TAFS THROUGH 00Z SATURDAY/
DETERIORATING CEILING CONDITIONS IN EXPANDING PRECIPITATION IS
ANTICIPATED OVERNIGHT S AND INTO MIDDAY FRIDAY. VFR CEILINGS
NOW WILL DROP INTO THE MVFR RANGE IN RAIN BY 12-15Z FROM
YKM/DLS/PSC/PDT/ALW. A FEW LOCATIONS COULD SEE THOSE LEVELS
APPROACH THE IFR CATEGORY OF 1000FT BY NOON (YKM/ALW).
PRELIMINARY POINT TEMPS/POPS
PDT 42 54 38 48 / 80 80 90 60
ALW 42 51 37 48 / 90 100 100 70
PSC 41 52 38 54 / 80 80 80 30
YKM 36 53 30 49 / 80 80 70 10
HRI 43 56 40 53 / 80 80 80 30
ELN 33 43 29 42 / 80 80 60 20
RDM 38 58 38 50 / 20 20 50 30
LGD 43 56 40 47 / 90 80 100 90
GCD 43 58 42 48 / 50 30 70 80
DLS 43 59 39 52 / 90 90 90 30
PDT WATCHES/WARNINGS/ADVISORIES
WA...WINTER STORM WARNING UNTIL 5 PM PDT FRIDAY FOR WAZ030-523.
WINTER STORM WARNING UNTIL 5 AM PDT SATURDAY FOR WAZ522.
OR...WINTER STORM WARNING UNTIL 5 PM PDT FRIDAY FOR ORZ502.
DISCUSSION...90
AVIATION...71
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