896
FXUS66 KPDT 221753
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1053 AM PDT THU OCT 22 2026
KEY MESSAGES
- RETURN OF SHOWERS AND ISOLATED THUNDERSTORMS TO THE EASTERN
MOUNTAINS TODAY
- BREEZY TO GUSTY WINDS DEVELOPING ACROSS THE AREA TONIGHT INTO
FRIDAY MORNING, WITH STRONGEST WINDS THROUGH THE CASCADE GAPS
- MODERATE-HIGH CONFIDENCE (65-80%) IN FREEZING MORNING
TEMPERATURES ACROSS LOWER ELEVATION AREA SATURDAY
DISCUSSION
AN UPPER TROUGH AND A COLD FRONT WILL MOVE ACROSS THE REGION
LATER TODAY AND TONIGHT, WITH LIMITED WEATHER IMPACTS FROM
WINDS, RAINS AND CONVECTION. A LIMITED CONVECTIVE THREAT TODAY
AS CAPES OVER THE EASTERN MOUNTAINS BROADLY 100-200 J/KG AND
HIGHER ELEVATED 400 J/KG POSE AN ISOLATED LIGHTNING RISK.
INITIALLY, THE REFS IS TRENDING TOWARD AN INITIAL WARM ADVECTION
INDUCED SWATH OF SHOWERS SUPPORTED BY THE REFS MEAN LIGHTING
FIELDS OF 0.02-0.05 FLASHES/ SQ KM/5 MINS. THIS FEATURE IS
FOCUSED ACROSS THE JOHN DAY BASIN AT 8 AM, AND ADVECTING ACROSS
PENDLETON/WALLA WALLA TOWARD THE TRI-CITIES BETWEEN ABOUT 9 AND
11 AM. THE TIME WINDOW FOR BEST RAIN ACCUMULATIONS IS BETWEEN
ABOUT 3 AND 12Z FRIDAY (8 PM THIS EVENING - 5 AM TOMORROW) WHEN
3 HOUR PROBABILITY MATCHED MEANS SHOW AREAS IN EXCESS OF A
QUARTER INCH EVERY 3 HOURS ACROSS THE FOOTHILLS BLUES MOUNTAINS
EASTWARD INTO WALLOWA COUNTY. THE HREF 24 HR PMMS ARE AT ABOUT
0.75 TO 1 INCH QPF ACROSS THESE AREAS AND AT LEAST WIDESPREAD
WETTING RAIN OVER THE ENTIRELY OF THE EASTERN MOUNTAINS.
A WIND ADVISORY REMAINS IN EFFECT ACROSS THE KITTITAS AND
EASTERN COLUMBIA RIVER GORGE ZONES FOR INCREASING WIND THIS
EVENING THROUGH MUCH OF THE OVERNIGHT AS THE POST FRONTAL
PRESSURE ISALLOBARIC PRESSURE RISES CAUSE CHANNELING EFFECTS
LEADING TO NBMS PROBABILITIES FOR GUSTS IN EXCESS OF 40 MPH
AVERAGING 50 TO 80 PERCENT, PARTICULARLY AROUND THE DALLES AND
ELLENSBURG.
LASTLY, COLD TEMPERATURES WILL RETURN ON THE BACKSIDE OF THIS
EXITING WEATHER SYSTEM FRIDAY NIGHT INTO SATURDAY MORNING,
BRINGING POTENTIAL FOR GROWING SEASON ENDING SUB FREEZING
TEMPERATURES ACROSS THE LOWER ELEVATIONS OF THE KITTITAS/YAKIMA
VALLEY, BLUE MT FOOTHILLS AND THE COLUMBIA BASIN.
AVIATION /18Z TAFS THROUGH 18Z FRIDAY/
VFR CONDITIONS
EXPECTED THROUGH THE PERIOD. A SYSTEM PASSING TO THE SOUTH WILL
BRING RAIN SHOWER IMPACTS TO SITES RDM/BDN THROUGH 00Z, PSC
THROUGH 02Z, AND SITES PDT/ALW THROUGH 08-09Z TONIGHT. BKN-OVC
CIGS ARE EXPECTED TO LOWER AFTER SUNSET AT SITES PDT/ALW THIS
EVENING, BUT SHOULD REMAIN AOA 4KFT AGL. A COLD FRONT PASSAGE
WILL BRING BREEZY CONDITIONS TO SITES DLS/PDT/RDM/BDN/YKM. AT
SITE DLS, WINDS WILL INCREASE TO 15-25KTS WITH GUSTS UP TO 40KTS
AFTER 22Z. SITES RDM/BDN WILL SEE WINDS INCREASE TO 12-15KTS
WITH GUSTS TO AROUND 20KTS BETWEEN 00Z-13Z. SITE YKM WINDS WILL
INCREASE TO 12-15KTS WITH GUSTS TO AROUND 23KTS BETWEEN 03Z-15Z.
SHORT-TERM MODEL GUIDANCE IS INDICATING LOW LEVEL WIND SHEAR
IMPACTS UP TO 2KFT AGL BETWEEN 03Z-15Z TONIGHT AT SITE YKM, BUT
CONFIDENCE IS LOW-MODERATE(30-40%) IN PERSISTENT WIND SHEAR
IMPACTS OVER THE SITE. LAWHORN/82
PRELIMINARY POINT TEMPS/POPS
PDT 58 36 56 27 / 80 70 0 0
ALW 59 40 57 32 / 80 80 0 0
PSC 62 38 64 29 / 70 50 0 0
YKM 67 39 64 31 / 0 0 0 0
HRI 59 39 61 30 / 70 50 0 0
ELN 66 33 57 26 / 0 0 0 0
RDM 60 25 51 19 / 60 10 0 0
LGD 66 37 53 25 / 70 100 20 0
GCD 65 36 53 25 / 80 90 20 0
DLS 69 43 62 34 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...WIND ADVISORY FROM 7 PM THIS EVENING TO 11 AM PDT FRIDAY FOR
WAZ024-026.
OR...WIND ADVISORY FROM 7 PM THIS EVENING TO 11 AM PDT FRIDAY FOR
ORZ041.
DISCUSSION...71
AVIATION...82
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page