964
FXUS66 KPDT 272351
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
451 PM PDT WED MAY 27 2026
.UPDATED AVIATION DISCUSSION.
KEY MESSAGES
- CHANCES OF THUNDERSTORMS FOR CENTRAL OREGON TODAY WITH MORE
WIDESPREAD COVERAGE ON THURSDAY. HAIL AND GUSTY WINDS ARE
POSSIBLE EMBEDDED IN THESE STORMS.
- MINOR HEAT RISK FOR TODAY, MODERATE HEAT RISK ON THURSDAY.
- BREEZY TO WINDY CONDITIONS DEVELOP ON FRIDAY.
DISCUSSION
AN UPPER LOW INTERMEDIATE SOUTH OF THE FORECAST AREA AND A WEAK
RIDGING TO THE NORTH WILL INFLUENCE SENSIBLE WEATHER OVER THE
NEXT 2 TO 3 DAYS ACROSS THE PDT FORECAST AREA. HEATRISK WILL
INCREASE FROM TODAY TO TOMORROW FORMING WIDESPREAD LIMITED RISK
(LEVEL 1) TO LEVEL 2 IN THE THE LOWER ELEVATION VALLEYS AND AND
COLUMBIA BASIN AS HIGH TEMPERATURES CLIMB INTO THE UPPER 80S AND
LOW 90S THROUGH THE COLUMBIA BASIN AND YAKIMA VALLEY. AFTERNOON
THUNDERSTORMS ACROSS CENTRAL OREGON A CROSS THE OCHOCO JOHN DAY
BASIN AND SOUTHERN BLUES ARE POSSIBLE BY LATE AFTERNOON AND
EARLY EVENING AND WILL LARGELY DIURNALLY DRIVEN (WEAKENING AFTER
SUNSET). FOR THURSDAY, STEEP MID LEVEL LAPSE RATES IN EXCESS OF
8.5 DEG C/KM WILL RESULT FROM COOLING AIR ALOFT AND SURFACE
HEATING CREATING WATER LOADED INVERTED V SOUNDINGS, WITH
ENOUGH MID LEVEL FLOWS TO CREATE WIND SHEAR CAPABLE OF LONG
SUSTAINED TSRA/CB AND DOWN BURST WIND THREAT. A GLANCE ACROSS
THE HREF CAMS VARY TEMPORALLY; INITIATING AND SPREADING
NORTHEAST OVER THE BLUE MOUNTAINS BETWEEN 22Z AND 01Z FOR THE
INITIAL BROKEN LINE OF STORMS, WHICH MAY LINGER FARTHER NORTH
INTO THE COLUMBIA BASIN AS THE EVENING PROGRESSES GIVEN AMPLE
PWATS (1.00"+) AND MEAN CAPE (1000-1500 J/KG). MUCH OF THE
FORECAST AREA HAS BEEN UPGRADED FROM 5% CHANCES FOR SEVERE
WEATHER FROM A POINT TO 15% CHANCES FOR THURSDAY AFTERNOON
(SLIGHT RISK).
FRIDAY LOOKS WINDY THROUGH THE KITTITAS VALLEY, SIMCOE
HIGHLANDS, EASTERN COLUMBIA RIVER GORGE AND THE COLUMBIA BASIN
OF OREGON, AS THE PRESSURE GRADIENTS INCREASE BEHIND A COLD
FRONT ASSOCIATED WITH THE EASTWARD PROPAGATING UPPER LOW. NBM
MEAN WIND GUSTS AVERAGE 40 TO 49 KNOTS IN THESE AREAS,
INDICATING HIGH END WIND ADVISORY CRITERIA.
AVIATION /00Z TAFS THROUGH 00Z FRIDAY/
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 EVENING,
SUBSIDING LATER TONIGHT. THESE TERMINALS WILL EXPERIENCE A
POTENTIAL FOR ISOLATED THUNDERSTORMS THIS EVENING. 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
HYDROLOGY
A GLANCE AT THE PWATS FOR THURSDAY AFTERNOON INDICATE ABOUT
1.00 INCH AVERAGE THROUGH THE BLUE MT FOOTHILLS AND LOWER
COLUMBIA BASIN, WHICH IS IN THE 75TH TO 99TH PERCENTILE FOR LATE
MAY COMPARED TO CLIMATOLOGY. AT ABOUT 0.8 PWAT ON AVERAGE
ALONG THE EASTERN CASCADES CREST, ARE ALSO ELEVATE AT AROUND THE
75TH PERCENTILE. A MARGINAL EXCESSIVE RAINFALL OUTLOOK IS
HIGHLIGHTED ACROSS THE EASTERN SLOPES OF THE CASCADES, AS WELL
AS INTO THE ADJACENT WASHINGTON VALLEYS INTO CENTRAL OREGON.
PRELIMINARY POINT TEMPS/POPS
PDT 50 85 51 70 / 0 10 50 10
ALW 56 86 58 73 / 0 20 50 10
PSC 53 92 55 78 / 0 0 50 10
YKM 56 93 56 75 / 0 10 70 40
HRI 52 88 54 72 / 0 0 60 20
ELN 54 89 53 66 / 0 10 70 50
RDM 44 80 42 62 / 30 80 90 40
LGD 48 85 49 70 / 20 30 60 40
GCD 43 81 44 68 / 40 60 50 60
DLS 59 90 56 69 / 0 10 90 20
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...NONE.
DISCUSSION...95
AVIATION...75
HYDROLOGY...99
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