189
FXUS66 KPDT 172330
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
429 PM PDT FRI APR 17 2026
.UPDATED AVIATION DISCUSSION.
KEY MESSAGES
- WARMER THROUGH TUESDAY
- BREEZY WITH CHANCES FOR SHOWER AND THUNDERSTORMS TUESDAY INTO
WEDNESDAY
DISCUSSION
THE SYNOPTIC PATTERN FEATURES AN UPPER RIDGE THAT WILL SLIDE
EAST OVER THE REGION OVER THE NEXT 12-24 HOURS, BRINGING HIGH
MID LEVEL (500 MB) RELATIVE HUMIDITY AND PLENTY OF MID LEVEL
CLOUD COVER. THIS PATTERN SHOULD RELEGATE TEMPERATURES TO ABOVE
FREEZING ACROSS ALL OF THE LOW LANDS AREAS FOR EARLY SATURDAY
MORNING. AFTERNOON HIGHS WILL TREND WARMER OVER THE NEXT 3 DAYS,
PEAKING ON MONDAY. AN INITIAL PUSH OF WEAK MOISTURE/INSTABILITY
MIGHT LEAD TO ISOLATED SHOWERS AND THUNDERSTORMS (LESS THAN 10%
LIGHTNING RISK) ACROSS THE OREGON CASCADES, FOLLOWED BY A MORE
ROBUST PUSH OF MOISTURE ALOFT AND LENDING TO HIGHER THUNDERSTORM
CHANCES (15 TO 20 %) CENTERED ACROSS THE FOOTHILLS OF THE
NORTHERN BLUE MOUNTAINS ON TUESDAY AFTERNOON AND TUESDAY NIGHT.
SURFACE BASED CAPES ARE MODELED AS HIGH AS AROUND 400 J/KG
ACROSS THESE MOUNTAIN ZONES. NBM MEAN WETTING RAINS ON THE 6
HOURLY BASIS FOLLOWING THE INITIAL ONSETS OF PRECIPITATION ARE
LIMITED TO THE HIGHER ELEVATION OF THE MOUNTAIN ZONES. ON THE 24
HOUR BASIS WETTING RAINS WILL BE AROUND 50% ACROSS THE LOWER
COLUMBIA BASIN. DRIEST AREAS AT THIS TIME LOOK TO BE CENTRAL
OREGON FROM MADRAS TO BEND AND THE YAKIMA AND AND KITTITAS
VALLEY AREAS FROM ELLENSBURG TO YAKIMA WHERE CHANCES FOR WETTING
RAINS OF 0.10” OR MORE ARE ONLY 25 TO 30%. A FAIR AMOUNT OF
UNCERTAINTY EXISTS WITH RESPECT TO ALL OF THESE FEATURES AS THE
THE DAY 5 CLUSTER ANALYSIS SHOWS A BALANCED DISTRIBUTION OF
CLUSTERS RANGING FROM A HEAVILY WEIGHTED GEPS SHOWING THE UPPER
LOW RIGHT OVER THE COAST APR 21/22 TO HEAVILY WEIGHTED GEFS THAT
IS MUCH FARTHER OFFSHORE. AS AN ALTERNATIVE SCENARIO, THE
LATTER OF THESE MIGHT LEAD TO A SLOWER PROGRESSION OF THEN
PATTERN DURING THE WEEK OR EVEN MORE MORE OF A A DRY SLOTTING
ACROSS CENTRAL OREGON. ASSUMING THE MEAN OF THESE SCENARIOS
DEVELOPS, TEMPERATURES ARE EXPECTED TO BE COOLER FROM WEDNESDAYS
INTO THURSDAY FOLLOWING THE PRECIPITATION MAKER, WITH NBM MEAN
HIGHS LIMITED TO THE LOW AND MID 60S ACROSS THE YAKIMA, KITTITAS
VALLEYS AND LOWER COLUMBIA BASIN/EASTERN GORGE ZONES, AND THE
MID 50S ACROSS CENTRAL OREGON. WEDNESDAY MIGHT BE THE MOST
BREEZY/WINDY OF THE DAY AS WELL ACROSS THE FOOTHILLS OF THE
NORTHERN BLUES AND THE SIMCOE HIGHLANDS.
AVIATION /00Z TAFS THROUGH 00Z SUNDAY/
VFR CONDITIONS CURRENTLY ACROSS ALL SITES, WHICH WILL STAY THE
COURSE THROUGH THE PERIOD. 25KFT CEILINGS WILL CONTINUE TO DEVELOP
THIS AFTERNOON AND EXTEND THROUGH EARLY SATURDAY MORNING AS WINDS
STAY LIGHT AND BELOW 10KTS. 75
PRELIMINARY POINT TEMPS/POPS
PDT 36 70 41 75 / 0 0 0 0
ALW 40 70 46 75 / 0 0 0 0
PSC 36 72 41 78 / 0 0 0 0
YKM 37 68 41 73 / 0 0 0 0
HRI 36 72 41 76 / 0 0 0 0
ELN 34 64 39 70 / 0 0 0 0
RDM 28 70 37 74 / 0 0 0 0
LGD 32 61 39 68 / 0 0 0 0
GCD 32 64 39 72 / 0 0 0 0
DLS 40 71 47 75 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...NONE.
DISCUSSION...71
AVIATION...75
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