317
FXUS66 KPDT 282037
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
137 PM PDT FRI MAR 28 2025
SHORT TERM
TONIGHT THROUGH SUNDAY NIGHT...LATEST RADAR SHOWED SOME ISOLATED
SHOWERS OVER NORTHEAST OREGON AND SOUTHEAST WASHINGTON MOVING OUT
OF THE AREA. LATEST GUIDANCE HAS SOME LINGERING POPS GENERALLY
OVER THE MOUNTAINS THROUGH SATURDAY AND THEN THE FIRST PART OF
SUNDAY IS DRY.
LOW PRESSURE OFF THE BRITISH COLUMBIA COAST WILL MOVE NORTHWARD
ALLOWING A TROUGH TO MOVE ONSHORE TONIGHT. THIS TROUGH WILL MOVE
ACROSS THE REGION ON SATURDAY BEFORE DEPARTING TO THE EAST LATER
SATURDAY.
A RIDGE WILL BE IN PLACE FOR SATURDAY AND SATURDAY NIGHT. BEFORE
IT IS DISPLACED TO THE EAST. THEN A SOUTHWEST TO TO FLOW WILL MOVE
INTO THE AREA LATER SUNDAY INTO SUNDAY NIGHT. THIS FLOW WILL ALLOW
FOR AN INCREASE IN MOISTURE FROM SOUTHWEST TO NORTHEAST AND WILL
BRING PRECIPITATION OVER MOST AREAS BY SUNDAY NIGHT.
QPF ACROSS MOST THE CRESTS OF THE CASCADES AND WALLOWA COUNTY
WILL BE 0.25 TO 0.50 INCHES THROUGH SATURDAY, WITH GENERALLY 0.10
INCHES OR LESS ELSEWHERE. MOST OF CENTRAL OREGON, THE COLUMBIA
BASIN AND YAKIMA VALLEY WILL REMAIN DRY.
SNOW LEVELS WILL INITIALLY START OUT BETWEEN 4000-5500 FEET
EVERYWHERE, BUT WILL DECREASE BY SATURDAY MORNING TO GENERALLY
LESS THAN 3000 FEET. THERE WILL BE SOME LIGHT NUISANCE, SNOW
AMOUNTS IN THE MOUNTAINS BUT LITTLE ACCUMULATION IS EXPECTED
OUTSIDE OF THE HIGHEST ELEVATIONS.
SNOW LEVELS WILL RISE AGAIN SUNDAY INTO SUNDAY NIGHT FROM
3000-3500 FEET TO 3500-500 FEET DURING THE DAY SUNDAY AND BACK TO
3500-4500 FEET SUNDAY NIGHT. QPF WILL BE MORE WIDESPREAD WITH
THIS EVENT, BUT GENERALLY LOWER, EXCEPT FOR THE OREGON CASCADES.
MOST LOCATIONS WILL GET ANYWHERE FROM A FEW HUNDREDTHS TO AROUND
0.10 INCHES. THE OREGON CASCADES WILL OVER 0.50 INCHES ALONG THE
CREST. AGAIN, GENERALLY LIGHT SNOW AMOUNTS ARE EXPECTED...LESS
THAN AN INCH WITH HIGHER AMOUNTS POSSIBLE AT THE HIGHEST
ELEVATIONS.
WINDS WILL BE A BIT BREEZY ON SATURDAY WITH GUSTS IN THE 15 TO 20
MPH RANGE, WITH SOME AREAS AS HIGH AS 25 MPH.
LONG TERM
MONDAY THROUGH FRIDAY...ENSEMBLE GUIDANCE HAS A PRETTY GOOD GRASP
ON THE SYNOPTIC PATTERN NEXT WORK WEEK. EXPECT A COOL AND WET
PATTERN WITH PERSISTENT HIGH MOUNTAIN SNOW AND INTERMITTENT
CHANCES FOR LIGHT, LOW-ELEVATION RAIN THROUGHOUT THE PERIOD, WITH
TEMPERATURES TRENDING TOWARDS SLIGHTLY BELOW AVERAGE BY THE END OF
THE WEEK.
MONDAY LOOKS TO BE THE WETTEST DAY OF THE PERIOD, THANKS TO A DEEP
SURFACE LOW CENTERED OFF THE PACIFIC COAST. THERE IS GOOD AGREEMENT
ACROSS MODELS, HOWEVER, THAT THE BULK OF THIS SYSTEM'S MOISTURE WILL
LIE TO OUR SOUTH, WITH THE LOW'S CENTER TRACKING OVERHEAD BY THE
MIDWEEK. AHEAD OF THE LOW, HOWEVER, WILL BE ENOUGH SW FLOW TO
TRIGGER WIDESPREAD LIKELY POPS, WITH SNOW LEVELS GENERALLY IN THE
3000-4000 FT RANGE. OUR MOUNTAIN PASSES AREN'T AT TOO MUCH OF A RISK
OF SEEING IMPACTFUL ACCUMULATING SNOWFALL AS A RESULT, BUT EXPECT A
DECENT DOSE OF MOISTURE ACROSS MUCH OF THE FORECAST AREA ON MONDAY,
EVEN IF THE HEAVIEST PRECIP DOES END UP OCCURRING TO OUR SOUTH.
FOR THE MIDWEEK ONWARD, THE SYNOPTIC PATTERN BECOMES MORE NW,
USHERING IN COOLER AIR AND ALLOWING SNOW LEVELS TO DROP CLOSER TO
THE 2000-3000 FT RANGE. WILL HAVE TO KEEP AN EYE OUT FOR THURSDAY,
AS ENSEMBLE CLUSTERING DOES HINT AT A SHORTWAVE DROPPING IN FROM THE
NORTHWEST, WHICH COULD PROVIDE OUR MOUNTAIN PASSES WITH A ROUND OF
ACCUMULATING SNOWFALL. CONFIDENCE THIS FAR OUT IS STILL ON THE LOWER
END, (30-40%) BUT GUIDANCE DOES SEEM TO BE CONVERGING AS OF NOW
TOWARDS THURSDAY BEING THE NEXT BEST DAY TO SEE AREA-WIDE PRECIP.
SLIGHTLY BEYOND THE LONG TERM, ENSEMBLES DO HINT AT NORTHWEST FLOW
BREAKING DOWN AND BEING REPLACED BY RIDGING, BUT EXPECT A DISTINCT
COOLDOWN FROM THE LATE-SPRING CONDITIONS WE SAW EARLIER THIS WEEK TO
KICK OFF APRIL. EVANS/74
AVIATION
(PREVIOUS DISCUSSION)
18Z TAFS...SCATTERED SHOWERS AND WINDS WILL BE THE MAIN AVIATION
IMPACTS DURING THE PERIOD. RADAR AND OBS SHOW LIGHT RAIN SHOWERS
CURRENTLY IMPACTING PDT AND ALW, WITH SOME ISOLATED ACTIVITY
POSSIBLE (20-30% CHANCE) FOR BDN AND RDM. ALL OTHER SITES EXPECTED
TO REMAIN DRY. BRIEF MVFR CONDITIONS ARE POSSIBLE UNDER SHOWERS,
BUT EXPECTATION IS THAT VFR CONDITIONS WILL PREVAIL THROUGH THE
PERIOD. WINDS WILL BE GUSTY AT MANY SITES, ESPECIALLY AT YKM WHERE
GUSTS GREATER THAN 30 KTS ARE CURRENTLY BEING OBSERVED.
ELSEWHERE, GUSTS WILL RANGE FROM ABOUT 15 TO 25 KTS. WIND
DIRECTION GENERALLY SW TO W. WINDS WILL THEN SLACKEN OVERNIGHT AND
GENERALLY BECOME TERRAIN-DRIVEN. CIGS BKN-OVC AROUND 5-10 KFT
THIS AFTERNOON, BEFORE CLEARING TAKES PLACE THIS EVENING AND
OVERNIGHT. EVANS/74
PRELIMINARY POINT TEMPS/POPS
PDT 38 56 34 62 / 10 10 0 0
ALW 40 55 36 61 / 10 10 0 0
PSC 38 61 34 64 / 0 0 0 0
YKM 33 59 34 59 / 0 0 0 0
HRI 38 60 33 64 / 10 0 0 0
ELN 34 56 33 57 / 0 10 0 0
RDM 28 54 30 59 / 10 0 0 10
LGD 35 49 28 54 / 40 40 0 0
GCD 32 49 28 54 / 50 10 0 20
DLS 39 59 38 61 / 10 10 0 10
PDT WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
SHORT TERM...77
LONG TERM....74
AVIATION...74
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