795
FXUS66 KPDT 171641
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
941 AM PDT TUE MAR 17 2026
KEY MESSAGES
- RAIN WILL CONTINUE ACROSS THE WASHINGTON CASCADES THROUGH
FRIDAY, BEFORE LESSENING OR ENDING OVER THE WEEKEND.
- THE RAIN WILL COMBINE WITH MELTING SNOW TO BRING RISING RIVERS
ACROSS THE AREA.
- MUCH WARMER TEMPERATURES CAN BE EXPECTED THROUGH FRIDAY.
DISCUSSION
HIGH PRESSURE TO THE SOUTH WILL BUILD OVER MUCH OF THE REGION
OVER THE NEXT SEVERAL DAYS. THIS HIGH WILL BRING GENERALLY DRY
WEATHER AND MUCH WARMER TEMPERATURES.
THE ONLY EXCEPTION WILL BE OVER THE WASHINGTON CASCADES, WHERE
RAIN WILL LINGER, FROM AN ATMOSPHERIC RIVER. DUE TO THE WARMING
TEMPERATURES SNOW LEVELS WILL RISE TO OVER 8000 FEET, SO ONLY
RAIN IS EXPECTED. QPF AMOUNTS ARE OVER 2 INCHES ALONG THE
WASHINGTON CASCADE CREST WITH SOME AMOUNTS LOCALLY CLOSE TO 3
INCHES. THESE RAINFALL AMOUNTS COUPLED WITH THE WARMING
TEMPERATURES WILL CAUSE A RISE IN RIVERS FED BY THE CASCADES,
NAMELY THE NACHES AND YAKIMA RIVERS. AT THIS TIME, ONLY THE
NACHES RIVER AT NACHES IS EXPECTED TO MAKE IT TO FLOOD STAGE,
BUT WE WILL WATCH THIS, AS QPF AMOUNTS HAVE TRENDED HIGHER.
ELSEWHERE, ACROSS THE AREA, THE CREST OF THE OREGON CASCADES AND
BLUE MOUNTAINS SHOULD RECEIVE AROUND 0.25 INCHES. THE LOWER
ELEVATIONS SHOULD BE DRY OR RECEIVE ONLY A HUNDREDTH OR TWO.
THE OTHER STORY THROUGH FRIDAY IS THE MUCH ABOVE NORMAL
TEMPERATURES. HIGHS WILL MAKE IT INTO THE LOW TO MID 70S
THURSDAY AND FRIDAY FOR PLACES LIKE CENTRAL OREGON, THE COLUMBIA
BASIN, AND FOOTHILLS OF THE BLUE MOUNTAINS. THIS WILL BE 15 TO
AS MUCH AS 20 DEGREES ABOVE NORMAL. THE ECMWF EFI IS KEYING IN
ON THESE ANOMALIES BEGINNING TODAY ACROSS CENTRAL AND SOUTHERN
OREGON AND SPREADING NORTH, WITH ANOMALIES AS HIGH AS 1.0. LOWS
ARE ALSO WARM, WITH MANY AREAS ONLY DROPPING INTO THE 40S, AND
BY THURSDAY NIGHT, THE COLUMBIA BASIN AND FOOTHILLS OF THE BLUE
MOUNTAINS MAY STAY IN THE 50S.
BY SATURDAY, THE HIGH PRESSURE MOVES EASTWARD AND THE FLOW
BECOMES MORE ZONAL ACROSS THE PACIFIC NORTHWEST. THIS WILL CAUSE
TEMPERATURES TO COOL BACK CLOSER TO NORMAL OVER THE AREA.
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
WESTERLY SURFACE WINDS UP TO 12 KNOTS ACROSS THE AREA TODAY
WILL BROADLY SLACKEN OVERNIGHT TO GENERALLY LIGHT (UNDER 5
KNOTS) AND SOUTH SOUTHWESTERLY. VFR CATEGORY IS ANTICIPATED FOR
ALL TERMINALS.
PRELIMINARY POINT TEMPS/POPS
PDT 69 43 71 47 / 10 10 0 0
ALW 66 48 70 52 / 20 20 0 10
PSC 69 47 72 49 / 10 10 0 0
YKM 67 44 69 47 / 20 20 10 10
HRI 69 43 72 47 / 10 10 0 0
ELN 58 42 61 43 / 40 40 30 20
RDM 73 38 76 40 / 0 0 0 0
LGD 68 43 74 46 / 10 10 0 0
GCD 70 43 74 45 / 0 0 0 0
DLS 66 44 69 46 / 20 10 10 10
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...NONE.
DISCUSSION...77
AVIATION...71
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