749
FXUS66 KPDT 222337
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
ISSUED BY NATIONAL WEATHER SERVICE SPOKANE WA
437 PM PDT TUE APR 22 2025
UPDATED AVIATION...00Z TAFS
VFR LEVELS WILL PERSIST THROUGH
THE 00Z PERIOD. A COUPLE OF FEW TO SCT MID-LEVEL CLOUDS CONTINUE
THROUGH THE CWA. LIGHT WINDS UP TO 10 KNOTS ARE EXPECTED THROUGH
THE PERIOD. ONLY EXCEPTION IS BDN AND RDM WITH UP TO 20 KNOT
GUSTS, BUT IS EXPECTED TO LIGHTEN TO AROUND 5 TO 10 KNOTS BY THE
NIGHT HOURS. NO PRECIP EXPECTED FOR THE AREA AND CIGS AND VIS
REMAIN WELL INTO VFR.
PREV DISCUSSION
/ISSUED ISSUED BY NATIONAL WEATHER SERVICE SPOKANE WA/
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
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...95
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