068
FXUS66 KPDT 101016
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
316 AM PDT WED JUN 10 2026
KEY MESSAGES
- ISOLATED TO SCATTERED MOUNTAIN SHOWERS THIS MORNING
- DIURNALLY BREEZY WINDS THROUGH THE CASCADE GAPS THROUGH FRIDAY
- DRY WITH NEAR-SEASONAL TEMPERATURES THURSDAY THROUGH SATURDAY,
THEN WARMER SUNDAY INTO EARLY NEXT WEEK
DISCUSSION
WATER VAPOR IMAGERY SHOWS A SHORTWAVE TROUGH DRAPED OVER
NORTHERN WASHINGTON AND SOUTHERN BRITISH COLUMBIA. THIS FEATURE
WILL SLIDE OVER THE PACIFIC NORTHWEST THROUGH THE DAY,
RESULTING IN CONTINUED MILD TEMPERATURES, BREEZY WESTERLY WINDS,
AND ISOLATED TO SCATTERED RAIN SHOWERS FOR THE MOUNTAINS.
NEAR-SEASONAL TEMPERATURES AND DRY WEATHER ARE THEN FORECAST
THURSDAY AND FRIDAY AS AN AMPLIFYING RIDGE OF HIGH PRESSURE
OFFSHORE COMBINES WITH DOWNSTREAM TROUGHING TO CREATE QUASI-
ZONAL FLOW OVER THE PACIFIC NORTHWEST. DIURNALLY BREEZY WESTERLY
WINDS WILL DEVELOP THROUGH THE CASCADE GAPS EACH AFTERNOON AND
EVENING. PROBABILISTIC GUIDANCE FROM THE NBM INDICATES A LOW
(10 PERCENT OR LESS) CHANCE OF RED FLAG CONDITIONS (COMBINATION
OF WIND AND LOW RELATIVE HUMIDITY) FOR THE LOWER COLUMBIA
BASIN.
BY LATE FRIDAY AND SATURDAY, ENSEMBLE GUIDANCE SHOWS SOME
SPREAD IN THE LOCATION/AMPLITUDE OF THE OFFSHORE RIDGE AND
TROUGHING OVER THE NORTHERN ROCKIES AND NORTHERN GREAT PLAINS.
WHILE CONFIDENCE IN ISOLATED PRECIPITATION IS CURRENTLY LOW (20
PERCENT OR LESS), THE APPROACHING SHORTWAVE (SHOULD IT DEVELOP)
COUPLED WITH THE OFFSHORE RIDGE AND WARMING TEMPERATURES WEST OF
THE CASCADES WOULD INDUCE A FLIP IN WIND DIRECTION TO OFFSHORE
(EASTERLY) FOR SATURDAY AND SUNDAY. PROBABILISTIC GUIDANCE FROM
THE NBM SUGGESTS LOW, BUT NOTEWORTHY, CHANCES (5-30 PERCENT) OF
RED FLAG CONDITIONS (COMBINATION OF BREEZY WINDS AND LOW
RELATIVE HUMIDITY) FOR THE COLUMBIA BASIN BOTH DAYS. GIVEN THE
LOW PROBABILITIES AND UNCERTAINTY IN THE 500-HPA PATTERN,
CONFIDENCE IS MUCH TOO LOW FOR ANY FIRE WEATHER HEADLINES AT
THIS TIME, BUT WILL CONTINUE TO MONITOR CLOSELY.
AS THE RIDGE EVENTUALLY MOVES INLAND (MONDAY AND TUESDAY BASED
ON LATEST 00Z ENSEMBLE NWP GUIDANCE), TEMPERATURES ARE FORECAST
TO RISE TO ABOVE NORMAL. THE NBM PLACES A 30-80 PERCENT CHANCE
OF EXCEEDING 90 DEGREES ACROSS ALL OF THE LOWER ELEVATIONS ON
MONDAY, WITH CHANCES INCREASING TO 60-95 PERCENT ON TUESDAY.
MOREOVER, THERE IS A 5-30 PERCENT CHANCE OF REACHING 100
DEGREES FOR THE LOWER ELEVATIONS OF THE COLUMBIA BASIN ON
TUESDAY.
PROBABILISTIC HEATRISK GUIDANCE INDICATES A 5-30 PERCENT CHANCE
OF MAJOR (LEVEL 3 OF 4) HEATRISK FOR THE MAJORITY OF OUR
POPULATION CENTERS WITHIN THE GREATER COLUMBIA BASIN REGION
MONDAY AND TUESDAY, A DECREASE FROM YESTERDAY'S GUIDANCE. THIS
LEVEL OF HEAT AFFECTS ANYONE WITHOUT COOLING/HYDRATION.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
BREEZY WESTERLY WINDS WILL PERSIST THOUGH THE OVERNIGHT HOURS
AND THROUGH MOST OF THE DAY WEDNESDAY BEFORE DROPPING TO LIGHT
(UNDER 12 KNOTS) BY WEDNESDAY EVENING. LIGHTER WINDS ARE
EXPECTED AT RDM AND BDN. SHOWERS REMAIN RELEGATED TO THE
MOUNTAIN ZONES, AND THE TERMINALS ARE LIKELY (95% CONFIDENCE) TO
REMAIN IN THE THE VFR CATEGORY (VISIBILITY GREATER THAN 5 SM
AND CEILINGS ABOVE 3,000 FT) FOR THE DURATION OF THE TAFS.
PRELIMINARY POINT TEMPS/POPS
PDT 69 41 78 49 / 10 0 0 0
ALW 70 47 79 53 / 20 0 0 0
PSC 75 44 82 50 / 0 0 0 0
YKM 74 44 82 51 / 0 0 0 0
HRI 73 43 81 51 / 0 0 0 0
ELN 65 40 76 47 / 0 0 0 0
RDM 68 34 81 43 / 0 0 0 0
LGD 63 38 78 44 / 50 0 0 0
GCD 65 36 81 43 / 0 0 0 0
DLS 71 47 82 54 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...NONE.
DISCUSSION...86
AVIATION...71
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