522
FXUS66 KPDT 172129
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
229 PM PDT TUE MAR 17 2026
KEY MESSAGES
- RECORD OR NEAR RECORD WARM HIGHS AND LOWS
- LOCALLY WINDY THURSDAY AND BEYOND
- BIG BREAK FROM THE UNSEASONABLY WARM TEMPERATURES ON
SATURDAY WITH A COLD FRONT
DISCUSSION
STATIONARY/STALLED ATMOSPHERIC RIVER UP TO 600 KG/MS MAGNITUDE
WILL CONTINUE UNDERGO OROGRAPHIC LIFT , BRINGING SEVERAL INCHES
OF RAIN TO THE WASHINGTON CASCADE CREST THROUGH THE END OF THE
WEEK. THIS IS OF HIGH CONFIDENCE (90-95%) AS SNOW LEVELS NOW AND
FOR THE NEXT FEW DAYS ARE AVERAGING 7000 TO 9000 FEET AGL OR
HIGHER. THIS WILL IMPACT AREA RIVERS WITH RUNOFF OVER SNOW AND
SOME MELTING AS WELL. THE LAST 24 HOURS HAVE SEEN UPWARDS OF
ABOUT 1 INCH ACROSS THIS FORECAST ZONE. MOST RIVER FORECAST
RESPOND WITH WITHIN BANK RISES; GOING TO NEAR OR ABOVE ACTION
STAGE HOWEVER THE NACHES RIVER AT NACHES DOES HAVE A FORECAST
HYDROGRAPH GOING INTO MINOR FLOOD STAGE SATURDAY, CRESTING
FRIDAY AFTERNOON THROUGH SATURDAY EVENING, AT THE LOW END OF THE
MINOR RANGE 17.8 FEET.
BREEZY TO WINDY CONDITIONS RETURN TO THE YAKIMA VALLEY AND
SIMCOE HIGHLANDS ON THURSDAY HOWEVER THOSE TRENDS DO NOT LOOK
QUITE AS STRONG ON THE MOST RECENT RUNS. NBM RANGE BOX AND
WHISKER PLOTS SHOW CLOSE TO TO JUST OVER ADVISORY (LOW END WITH
UP TO 45 MPH GUSTS) ON THE 75TH PERCENTILE ACROSS PARTS OF THESE
FORECAST ZONES. WINDY CONDITIONS HAVE THE POTENTIAL TO TREND
UPWARD THROUGH THE 4-7 DAY PERIOD AS 24 HR MAX 10M GUSTS
INCREASE TO A MORE BROAD AREA COVERING MORE OF THE COLUMBIA
BASIN AND AS FAR NORTH AS THE KITTITAS VALLEY FRIDAY INTO
SATURDAY, WHEN A COLD FRONT COMES INTO PLAY SCOURING OUT THE HOT
AIR OF THE LATE WEEK.
RECORD OR NEAR RECORD HIGHS AND LOWS ARE POSSIBLE GIVEN THE
LATEST TRENDS OF A LARGE AMPLIFIED WESTERN U.S RIDGE THAT WILL
EXTEND SUBSIDENT WARM AIR INTO OREGON THROUGH THE WEEK. THE ESAT
TABLE AND SHIFT OF TAILS CONTINUES TO TREND TOWARD AN EXTREME
TEMPERATURES EPISODE FOR OREGON WITH RESPECT TO MODEL
CLIMATOLOGY. EXPECTED TEMPERATURES FROM THE NBM MEAN ARE IN THE
LOW 70S ACROSS MOST OF THE LOWLANDS….MID TO UPPER 70S IN CENTRAL
OREGON AND HITTING AROUND 80 DEGREES THROUGH THE LOWEST BASINS
LIKE JOHN DAY AND THE DESCHUTES/JOHN DAY RIVER VALLEYS. BASED
ON THE TIMING OF THE STRONGEST WINDS IN THE HIGHEST ELEVATIONS
OF KLICKITAT COUNTY THE COLD FRONT PUSHES THROUGH AROUND LATE
FRIDAY AFTERNOON OR FRIDAY EVENING, DRIVING MEAN HIGH TEMPS DOWN
10 TO 15 DEGREES ON AVERAGE BETWEEN FRIDAY AND SATURDAY.
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 43 71 47 75 / 10 0 0 0
ALW 49 70 52 72 / 10 10 10 0
PSC 46 73 49 75 / 10 0 0 0
YKM 43 68 46 71 / 20 10 10 10
HRI 43 71 47 75 / 10 0 0 0
ELN 42 60 42 63 / 40 30 10 20
RDM 38 75 41 76 / 0 0 0 0
LGD 42 73 46 75 / 0 0 0 0
GCD 43 74 44 75 / 0 0 0 0
DLS 45 70 47 70 / 0 10 0 10
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...NONE.
DISCUSSION...71
AVIATION...71
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