100
FXUS66 KPDT 271750
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1050 AM PDT WED MAY 27 2026
.UPDATED AVIATION DISCUSSION.
KEY MESSAGES
- CHANCES OF THUNDERSTORMS FOR CENTRAL OREGON WEDNESDAY WITH
MORE WIDESPREAD COVERAGE ON THURSDAY. HAIL AND GUSTY WINDS ARE
POSSIBLE EMBEDDED IN THESE STORMS.
- MINOR HEAT RISK FOR TODAY AND THURSDAY, WITH GREATER RISK ON
THURSDAY BEFORE THUNDERSTORM DEVELOPMENT.
- BREEZY TO WINDY CONDITIONS DEVELOP ON FRIDAY.
DISCUSSION
OVERHEAD RIDGING WILL BRING DRY CONDITIONS IN THE SHORT TERM,
WITH THE CUT-OFF LOW PRESSURE SYSTEM SITUATED OVER NEVADA AND
CALIFORNIA BRINGING ENOUGH LIFT TO INITIATE ISOLATED
THUNDERSTORMS IN CENTRAL OREGON THROUGH WEDNESDAY. SUFFICIENT
DAYTIME HEATING THROUGH THURSDAY WILL BUILD MINOR HEAT RISK
ACROSS THE REGION WITH VALUES OF "1" ON WEDNESDAY, WITH MORE
WIDESPREAD POCKETS OF "2" ON THURSDAY (70-90% CHANCE). HIGH
TEMPERATURES WILL CLIMB INTO THE HIGH 80S TO LOW 90S BY
THURSDAY. CONSEQUENTLY, THIS WILL ENABLE THUNDERSTORM
DEVELOPMENT WITH ABUNDANT ATMOSPHERIC ENERGY IN THE LATER
AFTERNOON HOURS THURSDAY, INCREASING OUR CHANCES OF
THUNDERSTORMS ACROSS THE REGION TO 30-40%.
GFS DETERMINISTIC ADVERTISES HIGH CAPE VALUES OF UP TO 1200
J/KG AND DEW POINT VALUES IN THE MID TO HIGH 50S, WITH THE
HIGHEST VALUES SITUATED ACROSS THE FOOTHILLS OF THE BLUES AND
GOING UP INTO THE NORTHERN BLUE MOUNTAINS. ECMWF BACKS UP HIGHER
THAN USUAL CAPE VALUES THURSDAYS WITH RELATIVE FORECASTS OF 0.7
TO 0.91 AND A SHIFT OF TAILS OF 0 TO 1. WIDESPREAD LOW-LEVEL
LAPSE RATES OF 8.8 TO 9.2 DEGREES IS PRESENT WITH MID-LEVEL
RATES BETWEEN 8.2 TO 8.7 DEGREES. LOOKING AT SOUNDINGS, THERE'S
AN APPARENT CAP AT AROUND 800 MB THAT IS PREVENTING THE STORMS
FROM TAPPING INTO THE FULL AVAILABLE ENERGY. DEPENDING ON
WHETHER STORMS CAN OVERCOME THE CAP WILL DETERMINE IF STORMS
WILL BE STRONGER THAN ANTICIPATED. PER SPC, THE ENTIRE CWA IS
FULLY IN A MARGINAL RISK THURSDAY WITH 5% CHANCES OF SEVERE WIND
AND/OR HAIL EMBEDDED WITH THESE STORMS. REGARDLESS, GUSTY
OUTFLOWS IS LIKELY FROM ANY STRONG DEVELOPING STORMS, BRINGING
ERRATIC 40-60 MPH GUSTS.
FOR FRIDAY, A COLD FRONT PASSES THROUGH THE REGION THAT WILL
DEVELOP TIGHT PRESSURE GRADIENTS AND BRING ALONG BREEZY TO
GUSTY WINDS ACROSS THE REGION. THUNDERSTORM FORMATION WILL BE
LIMITED TO THE EASTERN PART OF THE CWA NEAR THE WALLOWAS AND
PARTS OF THE FOOTHILLS OF THE WA BLUES (15 TO 25% CHANCE) AS THE
LOW MOVES OFF TO THE EAST. CONDITIONS QUICKLY BECOME MORE DRY
OVER THE WEEKEND AS THE PATTERN BECOMES MORE ZONAL/SLIGHTLY
RIDGED OVER THE PACNW AND A WARMING TREND CONTINUES.
AVIATION /18Z TAFS THROUGH 18Z THURSDAY/
VFR CONDITIONS CURRENTLY ACROSS ALL SITES, WHICH WILL STAY THE
COURSE THROUGH THE PERIOD. BREEZY 20-30KT WIND GUSTS ARE
OCCURRING FOR KRDM/KBDN AND PERSIST THROUGH THE AFTERNOON AND
EVENING, SUBSIDING LATER THIS EVENING. THESE TERMINALS WILL
EXPERIENCE RAIN SHOWERS LATER TODAY, AND THE POTENTIAL FOR
ISOLATED THUNDERSTORMS THROUGH THE AFTERNOON. ANY THUNDERSTORMS
THAT DEVELOP WILL INCLUDE BREEZY AND ERRATIC WINDS, BRIEF HAIL,
AND PERIODS OF HEAVY RAINFALL. ALL REMAINING TERMINALS WILL STAY
DRY WITH WINDS OF 10KTS OR LESS. 75
PRELIMINARY POINT TEMPS/POPS
PDT 79 50 85 51 / 0 10 10 50
ALW 81 56 86 58 / 0 0 20 50
PSC 85 53 92 55 / 0 0 0 50
YKM 87 56 93 56 / 0 0 10 70
HRI 82 52 88 54 / 0 0 0 60
ELN 82 54 89 53 / 0 0 10 70
RDM 78 44 80 42 / 0 30 80 90
LGD 79 48 85 49 / 10 30 30 60
GCD 79 43 81 44 / 10 40 60 50
DLS 86 59 90 56 / 0 0 10 90
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...NONE.
DISCUSSION...95
AVIATION...75
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