453
FXUS66 KPDT 091138
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
438 AM PDT THU APR 9 2026
KEY MESSAGES
- RAIN CHANCES INCREASE INTO THE WEEKEND WITH MAINLY HIGHLAND AND
MOUNTAIN THUNDERSTORMS IN OREGON FRIDAY INTO SATURDAY.
- COOLER, MORE SEASONABLE TEMPERATURES SUNDAY INTO NEXT WEEK.
DISCUSSION
A DRY AND MILD SETUP CONTINUES TODAY AS HIGH PRESSURE DOMINATES
THE SENSIBLE WEATHER WITH WARM TEMPERATURES ONCE AGAIN IN THE
60S AND 70S. SOME OF THE WARMER AREAS WILL AGAIN BE THE GRANDE
RONDE, YAKIMA AND KITTITAS VALLEYS, CENTRAL OREGON AND THE LOWER
COLUMBIA BASIN WHERE TEMPERATURES NEARING OR SURPASSING THE 70
DEGREE THRESHOLD WILL BE LIKELY BASED ON THE THE BULK OF THE NBM
MAXT MEMBERS. AREAS FROM YAKIMA TO TOPPENISH AND SUNNYSIDE HAVE
A 60 TO 70% CHANCE OF EXCEEDING 70 DEGREES THIS AFTERNOON.
LIKEWISE THE TRI-CITIES IS MOST LIKELY TO BE IN THE LOW 70S AT
80% CHANCES.
IN ADDITION TO THE WARM CONDITIONS A GENERAL THUNDERSTORMS RISK
OUTLOOK SHIFTS INLAND AND NORTHWARD OVER THE NEXT 2-3 DAYS
MAXIMIZING ON SATURDAY WITH THE HIGHEST RISK FOR THUNDERSTORM
IMPACTS OVER CENTRAL OREGON AND THE EASTERN MOUNTAINS. FOR THIS
AFTERNOON, INCREASING MUCAPES AND SBCAPES OF AN AVERAGE OF 250
J/KG IS LIMITED IN AREAL COVERAGE TO THE CENTRAL OREGON AREAS
LATE IN THE DAY, AND QUICKLY DIMINISHING WITH THE LOSS OF PEAK
HEATING. IN ADDITION THE SHEAR IS THERE FOR BRIEF ORGANIZATION,
AT 200-300 M2/S2 0-3KM SRH. AS A LOW OFF THE PACIFIC COAST
MOVES INLAND, FRIDAY'S MUCAPES INCREASE AND EXPAND ACROSS A
LARGER AREAS INCLUDING THE JOHN DAY HIGHLANDS AND EASTERN
MOUNTAINS, AS HREF 4-HOUR BASED THUNDERSTORMS PROBABILITIES RAMP
UP FROM 20 TO 50% BETWEEN ABOUT 1 AND 6 PM IN THESE AREAS. BY
SATURDAY MORNING, THERE IS A 95% AND 70% CHANCES RESPECTIVELY
FOR WETTING RAINS (ONE TENTH OF AND INCH OR MORE) ACROSS THE
EASTERN SLOPES OF THE OREGON CASCADES, AND THE OCHOCO/JOHNDAY
HIGHLANDS WITH A 50% CHANCE EXTENDING ACROSS THE BLUE MOUNTAINS
AS FAR NORTH AS THE TOLLGATE AREA. BY SUNDAY MORNING,THE 48 HOUR
BASED TOTAL MEAN RAINFALLS FROM THE NBM ARE RIGHT ABOUT 0.4 TO
0.5 INCHES ACROSS THESE MOUNTAINS AND HIGHLAND AREAS, AND AT
LEAST WETTING RAINS OVER THE BASINS AND VALLEYS. BY SUNDAY THESE
THUNDERSTORM PROBABILITIES ARE ONCE AGAIN MINIMAL (SUB 10%)
OVER THE BROADER AREA, ALTHOUGH SOME LINGERING 15-20% CHANCES
ARE FORECAST BASED ON NBM ENSEMBLES ACROSS THE NORTHERN BLUE
MOUNTAINS.
AVIATION /12Z TAFS THROUGH 12Z FRIDAY/
HIGH PRESSURE STILL INFLUENCES THE REGION AS MOST SITES HAVE NO
LOW OR EVEN MID LEVEL CIGS THROUGH THE TAF AND LIGHT SURFACE
WINDS. RDM AND BDN HAS A 15-20% CHANCE FOR SHOWERS LATER IN THE
AFTERNOON.
PRELIMINARY POINT TEMPS/POPS
PDT 69 42 67 45 / 0 0 20 40
ALW 69 45 67 50 / 0 0 20 50
PSC 73 43 72 48 / 0 0 10 40
YKM 70 43 72 46 / 0 0 0 30
HRI 72 42 70 47 / 0 0 10 40
ELN 66 39 68 45 / 0 0 0 30
RDM 70 39 66 40 / 20 40 40 70
LGD 69 41 69 44 / 0 0 40 60
GCD 71 44 64 43 / 20 20 80 70
DLS 74 48 72 51 / 0 10 10 60
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...NONE.
DISCUSSION...71
AVIATION...71
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