370
FXUS66 KPDT 152331
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
431 PM PDT WED APR 15 2026
KEY MESSAGES
- MOUNTAIN SNOW INTO THURSDAY
- BREEZY TO WINDY THROUGH THURSDAY
- NEAR- TO SUB-FREEZING MORNING LOWS THURSDAY AND FRIDAY FOR THE
LOWLANDS
DISCUSSION
SATELLITE IMAGERY SHOWS A CLOSED UPPER LOW CENTERED OVER
SOUTHWEST BRITISH COLUMBIA EARLY THIS AFTERNOON. MEANWHILE, A
ROBUST COLD FRONT IS TREKKING ACROSS EASTERN OREGON AND FAR
SOUTHEAST WASHINGTON. IN THE WAKE OF THE FRONT, SKIES HAVE
BECOME CLEAR TO PARTLY CLOUDY ACROSS MUCH OF THE COLUMBIA BASIN
AND VICINITY, WITH UPSLOPE CONVECTIVE SHOWERS NOTED ACROSS THE
CASCADE CREST. WINTER WEATHER HEADLINES REMAIN IN EFFECT, AND
CONFIDENCE IS HIGH (80 PERCENT) IN AN ADDITIONAL 2-6 INCHES OF
SNOWFALL FOR THE WASHINGTON CASCADES AND NORTHERN BLUE
MOUNTAINS, AND 4-8 INCHES FOR THE OREGON CASCADES. WHILE THE
BULK OF THE STEADY SNOWFALL HAS ENDED FOR THE CASCADES -- AND
WILL END THROUGH THIS AFTERNOON FOR THE BLUES AS THE FRONT SAGS
SOUTHEAST -- SNOW SHOWERS WILL PERSIST THROUGH TONIGHT INTO
THURSDAY MORNING AS THE AFOREMENTIONED UPPER LOW MOVES OVER
NORTHEAST WASHINGTON.
BREEZY WESTERLY TO NORTHWESTERLY WINDS HAVE DEVELOPED IN THE
WAKE OF THE FRONT AND REMAIN DIURNALLY BREEZY TO WINDY THROUGH
THURSDAY. WHILE WINDS OF 20-30 MPH COUPLED WITH GUSTS OF 30-40
MPH HAVE DEVELOPED IN CLIMATOLOGICALLY WIND-PRONE LOCATIONS,
CONFIDENCE IN THE NEED FOR ANY WIND HEADLINES IS LOW-MEDIUM
(30-60 PERCENT), HIGHEST FOR THE KITTITAS VALLEY, EASTERN
COLUMBIA RIVER GORGE, LOWER COLUMBIA BASIN, AND FOOTHILLS OF THE
BLUE MOUNTAINS. WINDS WILL BE LOCALLY STRONGER ALONG EXPOSED
RIDGES WITHIN THE COLUMBIA PLATEAU REGION.
THE COLD AIR MASS ASSOCIATED WITH THE LOW HAS PROMPTED CONCERNS
FOR NEAR- TO BELOW-FREEZING MORNING TEMPERATURES. NBM
CALIBRATED PROBABILITIES STILL SUGGEST MEDIUM-HIGH CHANCES
(60-90 PERCENT) OF FREEZING TEMPERATURES FOR THE YAKIMA AND
KITTITAS VALLEYS, MEDIUM PROBABILITIES (30-70 PERCENT) ALONG THE
FOOTHILLS OF THE BLUE MOUNTAINS, AND LOW-MEDIUM (20-50 PERCENT)
FOR THE LOWEST ELEVATIONS INCLUDING THE EASTERN COLUMBIA RIVER
GORGE AND LOWER COLUMBIA BASIN. FREEZE WARNINGS REMAIN IN EFFECT
FOR TONIGHT INTO THURSDAY MORNING WHERE CHANCES OF FREEZING ARE
HIGHEST (KITTITAS AND YAKIMA VALLEYS AND THE FOOTHILLS OF THE
NORTHERN BLUE MOUNTAINS OF OREGON). WILL NOTE THERE IS STILL
UNCERTAINTY IN HOW MUCH CLOUD COVER WILL PERSIST AND HOW WINDY
CONDITIONS WILL REMAIN OVERNIGHT INTO THE MORNING HOURS, SO
CONFIDENCE IN WIDESPREAD FREEZING TEMPERATURES IS SHAKY (50-60
PERCENT), BUT THINK AREAS OF FREEZING TEMPERATURES STILL HAVE A
HIGH ENOUGH CHANCE OF DEVELOPING TO RETAIN THE WARNINGS.
AN UPPER-LEVEL RIDGE WILL LIKELY (90 PERCENT CONFIDENCE) BUILD
INTO THE PACIFIC NORTHWEST FRIDAY INTO THE WEEKEND, YIELDING
LIGHTER WINDS AND MOSTLY DRY CONDITIONS. THE MAIN HEADLINE-
WORTHY CONSIDERATION FOR FRIDAY WILL BE NEAR- TO SUB-FREEZING
TEMPERATURES FOR THE LOWLANDS. THIS SET-UP LOOKS MORE FAVORABLE
FOR MOSTLY CLEAR TO CLEAR SKIES AND LIGHTER WINDS RELATIVE TO
THURSDAY MORNING, SO WHILE THE COLDEST AIR MASS WILL HAVE EXITED
THE REGION TO THE EAST, RADIATIONAL COOLING SHOULD BE MORE
EFFICIENT. HAVE NOT ISSUED ANY FREEZE WATCHES TO AVOID CONFUSION
GIVEN THE EXISTING FREEZE WARNINGS FOR THURSDAY MORNING.
UNCERTAINTY IN THE 500-HPA PATTERN GROWS THROUGH THE WEEKEND,
BUT SOME FLAVOR OF A 500-HPA CLOSED LOW IS ADVERTISED BY ALL
ENSEMBLE CLUSTERS TO BE IN THE VICINITY OF THE PACIFIC
NORTHWEST SATURDAY THROUGH THE REMAINDER OF THE PERIOD.
PRECIPITATION CHANCES INCREASE SUNDAY, BUT ESPECIALLY MONDAY AND
TUESDAY, IN WHAT IS LOOKING INCREASINGLY LIKE A POTENTIAL
CONVECTIVE SET-UP FOR PORTIONS OF THE FORECAST AREA. ANOTHER
DEFORMATION BAND SIMILAR TO WHAT WAS OBSERVED EARLIER IN THE
WEEK IS ALSO LOOKING LIKE A POTENTIAL OUTCOME SHOULD THE CLOSED
LOW TRACK INLAND ALONG A SUPPORTIVE PATH, BUT CONFIDENCE IN
THAT SOLUTION IS CURRENTLY LOW (20-25 PERCENT).
AVIATION /00Z TAFS THROUGH 00Z FRIDAY/
THE REGION IS IN A POST COLD FRONTAL REGIME, AND WINDS WILL
REMAIN GUSTY BEHIND THIS FRONT FOR THE BALANCE OF TODAY AND
TONIGHT. GUSTS WILL GRADUALLY DIMINISH TO THE 20 TO 30 MPH RANGE
DURING THE OVERNIGHT HOWEVER, THROUGH THIS EVENING GUSTS OF 30
TO 40 MPH WILL STILL BE COMMON AT MOST OF THE TERMINALS. IFR
CONDITIONS HOWEVER HAVE ENDED AND A VFR FORECAST IS ANTICIPATED
FOR THE REST OF THE TONIGHT.
PRELIMINARY POINT TEMPS/POPS
PDT 31 53 32 57 / 30 10 0 0
ALW 34 54 36 57 / 50 30 0 0
PSC 34 61 34 63 / 20 0 0 0
YKM 30 59 31 61 / 10 0 0 0
HRI 32 59 34 62 / 20 0 0 0
ELN 29 51 30 57 / 10 0 0 0
RDM 22 48 21 57 / 40 10 0 0
LGD 28 46 29 54 / 70 40 10 0
GCD 25 45 25 54 / 70 40 0 0
DLS 35 56 35 63 / 40 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...WINTER WEATHER ADVISORY UNTIL 11 PM PDT THIS EVENING FOR
WAZ030-522.
FREEZE WARNING FROM 11 PM THIS EVENING TO 9 AM PDT THURSDAY
FOR WAZ026-027.
OR...WINTER WEATHER ADVISORY UNTIL 11 PM PDT THIS EVENING FOR
ORZ502.
FREEZE WARNING FROM 11 PM THIS EVENING TO 9 AM PDT THURSDAY
FOR ORZ507.
WINTER STORM WARNING UNTIL 5 AM PDT THURSDAY FOR ORZ509.
DISCUSSION...86
AVIATION...71
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