064
FXUS66 KPDT 230448
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
ISSUED BY NATIONAL WEATHER SERVICE SPOKANE WA
948 PM PDT TUE APR 22 2025
UPDATED AVIATION
SHORT TERM...TODAY THROUGH THURSDAY
FEW CLOUDS CURRENTLY
LINGER AROUND THE KITTITAS AND YAKIMA VALLEY INCLUDING PORTIONS OF
THE NORTHERN BLUES AND NORTHERN BLUE MOUNTAIN-FOOTHILLS.
OTHERWISE, MAINLY CLEAR SKIES WILL CONTINUE THROUGH TONIGHT WITH
OCCASIONAL BREEZES (20 MPH OR LESS) AT THE SOUTHERN BLUE MOUNTAIN-
FOOTHILLS AND CENTRAL OR FROM THE WESTERLY FLOW. LOW TEMPERATURES
MAY REACH TO NEAR OR SUB-FREEZING OVER THE BLUES AND THE CASCADES
FOR TONIGHT INTO TOMORROW MORNING. TOMORROW INTO THURSDAY
MORNING, THE UPPER- LEVEL HIGH PRESSURE MOVES OVER TO THE PACNW
WITH WARM DRY CONDITIONS AND CLEAR SKIES. AND AS THE NORTHWESTERLY
FLOW TAKES OVER, WINDS WILL BE LOCALLY BREEZY UP TO 20 MPH
TOMORROW AFTERNOON INTO EARLY EVENING. HIGH TEMPERATURES WILL BE
SEASONABLY WARM FOR THE AFOREMENTIONED DAYS AND THE REST OF THIS
FORECAST PERIOD.
THURSDAY EVENING ONWARDS, THE RIDGE WILL THEN BREAK DOWN AS THE
SHORTWAVE TROUGH APPROACHES FROM OR COAST TO THE PACNW. THE
WEATHER WILL GRADUALLY BECOME UNSTABLE AS LIGHT RAIN DEVELOPS AT
OCHOCO-JOHN DAY HIGHLANDS. THE RAW ENSEMBLES FAVOR LESS THAN 20%
PROBABILITY OF QPF AMOUNTS UP TO 0.10 OVER THE LOWER PART OF THE
EAST SLOPES OF OR CASCADES, THOUGH INCREASES AS THE TROUGH MOVES
CLOSELY ONSHORE. WINDS COULD BECOME SLIGHTLY BREEZY AROUND
PORTIONS OF THE CASCADES GAPS, BUT CHANCES ARE LOW (<30%).
FEASTER/97
LONG TERM...FRIDAY THROUGH TUESDAY
MODELS ARE IN GOOD
AGREEMENT ABOUT AN UPPER LOW AND TROUGH MOVING INTO THE PACIFIC
NORTHWEST FRIDAY THROUGH THE WEEKEND THOUGH THERE ARE SOME
DISAGREEMENTS ABOUT THE EXACT PATH THE LOW AND TROUGH WILL TAKE.
DESPITE THESE DIFFERENCES, MODELS ALL SHOW RAIN ACROSS THE AREA
FRIDAY THROUGH SATURDAY NIGHT, BEING CONFINED MAINLY TO THE
MOUNTAINS SUNDAY AND THEN TAPERING OFF SUNDAY NIGHT. MODELS ALSO
AGREE IN HAVING THE TROUGH MOVING INTO THE ROCKIES MONDAY WITH A
RIDGE BUILDING OFFSHORE FOR A DRIER AND WARMER DAY. MODELS MOSTLY
AGREE (80%) IN HAVING THE RIDGE CONTINUE TUESDAY THOUGH SOME GFS
AND CANADIAN ENSEMBLE MEMBERS WANT TO BRING ANOTHER SYSTEM ON
TUESDAY. THE EXTREME FORECAST INDEX HIGHLIGHTS BREEZY TO WINDY
CONDITIONS SATURDAY THROUGH MONDAY WITH VALUES OF AROUND 0.67
SATURDAY AND MONDAY AND 0.82 ON SUNDAY. OTHERWISE, NO
SIGNIFICANTLY UNUSUAL WEATHER IS EXPECTED. OVERALL MODEL
CONFIDENCE IS ABOVE AVERAGE BUT DROPS TO AVERAGE BY TUESDAY.
FRIDAY STARTS OUT WITH A CHANCE OF SHOWERS MOVING INTO THE
CASCADES AND CENTRAL OREGON FROM THE SOUTHWEST IN THE MORNING
AND SPREADING ACROSS THE REST OF THE AREA IN THE AFTERNOON AND
FRIDAY NIGHT. RAIN AMOUNTS LOOK TO BE UP TO A QUARTER INCH IN THE
MOUNTAINS AND UP TO A TENTH OF AN INCH IN CENTRAL OREGON WITH
LIGHTER AMOUNTS IN THE REST OF THE LOWER ELEVATIONS. SNOW LEVELS
ARE 6000-7000 FEET, SO ONLY THE HIGHEST PEAKS WILL SEE SNOW. NBM
PROBABILITIES ARE MORE PESSIMISTIC ABOUT QPF WITH A 30 PERCENT
CHANCE OF A QUARTER INCH IN THE CASCADES AND MUCH LOWER CHANCE
ELSEWHERE. TEMPERATURES WILL BE WELL ABOVE NORMAL WITH LOWER TO
MID 70S IN THE COLUMBIA BASIN, THOUGH INCREASING CLOUDINESS WILL
KEEP CENTRAL OREGON IN THE LOWER TO MID 60S WHILE THE MOUNTAINS
ARE IN THE MID 50S TO LOWER 60S. WINDS WILL REACH 10 TO 15 MPH
FROM THE WEST IN THE AFTERNOON.
ON SATURDAY, MODELS BRING THE LOW AND TROUGH OVERHEAD THOUGH WITH
DIFFERENCES AS TO WHETHER THE SYSTEM WILL BE CENTERED OVER
NORTHERN OR CENTRAL CALIFORNIA. EITHER WAY IT WILL KEEP A CHANCE
OF RAIN OVER MOST OF THE AREA SATURDAY THEN THE LOWER ELEVATIONS
BEGIN DRYING OUT SATURDAY NIGHT. RAIN AMOUNTS ARE LIGHTER WITH UP
TO A TENTH OF AN INCH IN THE MOUNTAINS AND JUST A FEW HUNDREDTHS
IN THE LOWER ELEVATIONS. MOST OF THE AREA WILL HAVE WESTERLY WINDS
OF 10 TO 20 MPH IN THE AFTERNOON BUT IT WILL REACH 20 TO 30 MPH
IN THE COLUMBIA GORGE AND KITTITAS VALLEY. TEMPERATURES DROP ABOUT
5 DEGREES TO THE MID 60S TO LOWER 70S IN THE COLUMBIA BASIN AND
MAINLY IN THE 50S ELSEWHERE.
BY SUNDAY, 82 PERCENT OF THE MODEL ENSEMBLE MEMBERS HAVE THE
TROUGH DIVING INTO SOUTHERN NEVADA OR UTAH. A SLIGHT CHANCE OF
SHOWERS LINGERS IN THE EASTERN MOUNTAINS THOUGH AMOUNTS ARE JUST A
FEW HUNDREDTHS OF AN INCH. WITH LOW PRESSURE TO THE SOUTHWEST AND
HIGHER PRESSURE OFFSHORE, THE AREA WILL GET STRONGER WEST TO
NORTHWEST WINDS OF 15 TO 25 MPH IN MOST OF THE LOWER ELEVATIONS
AND 25 TO 35 MPH IN THE KITTITAS VALLEY. TEMPERATURES ARE A DEGREE
OR TWO COOLER THAN SATURDAY.
MONDAY LOOKS LIKE A DRY AND WARMER DAY AS A RIDGE BUILDS OFFSHORE
WITH HIGH TEMPERATURES REMAINING IN THE MID 60S TO LOWER 70S IN
THE COLUMBIA BASIN AND WARMING SEVERAL DEGREES TO THE MID 60S TO
MID 70S IN THE MOUNTAINS. WINDS ARE LIGHTER, BUT STILL FROM THE
WEST REACHING 15 TO 20 MPH IN THE COLUMBIA BASIN AND KITTITAS
VALLEY. TUESDAY LOOKS SIMILAR BUT DUE TO THE MINORITY VIEW OF
MOUNTAIN SHOWERS, HAVE A SLIGHT CHANCE OF SHOWERS IN THE
AFTERNOON. TEMPERATURES ARE A COUPLE OF DEGREES WARMER THAN
MONDAY. PERRY/83
AVIATION...06Z TAFS
VFR CONDITIONS ARE FORECAST FOR ALL SITES
THROUGH THE VALID PERIOD. SKIES WILL BE MOSTLY CLEAR.
DIURNALLY AND TERRAIN-DRIVEN WINDS OF 10 KTS OR LESS, WITH
INTERMITTENT HIGHER GUSTS WEDNESDAY AFTERNOON, WILL PREVAIL.
PLUNKETT/86
PRELIMINARY POINT TEMPS/POPS
PDT 36 66 38 71 / 0 0 0 0
ALW 38 66 41 71 / 0 0 0 0
PSC 35 71 38 76 / 0 0 0 0
YKM 37 69 40 73 / 0 0 0 0
HRI 35 70 38 75 / 0 0 0 0
ELN 36 68 38 71 / 0 0 0 0
RDM 28 65 30 71 / 0 0 0 0
LGD 32 62 34 68 / 0 0 0 10
GCD 31 63 33 68 / 0 0 0 10
DLS 40 71 42 76 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
SHORT TERM...97
LONG TERM....83
AVIATION...86
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