471
FXUS66 KPDT 181843
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1143 AM PDT SAT JUL 18 2026
KEY MESSAGES
- CRITICAL FIRE WEATHER CONDITIONS CONTINUE THROUGH THE COLUMBIA
BASIN OF OREGON THROUGH 10 PM TONIGHT DUE TO BREEZY WINDS AND
LOW RELATIVE HUMIDITIES.
- WIDESPREAD MODERATE/MAJOR HEATRISK DEVELOPING THROUGH EARLY
NEXT WEEK.
- ELEVATED FIRE WEATHER CONDITIONS PERSIST THROUGH THE NEXT
SEVERAL DAYS WITH LOW RELATIVE HUMIDITIES AND DIURNAL BREEZY
WINDS DEVELOPING.
UPDATE
RED FLAG WARNING ISSUED FOR KITTITAS/YAKIMA VALLEY ZONE WA690
THROUGH 10 PM FOR WINDS AND RELATIVE HUMIDITIES. WINDS FROM THE
NORTHWEST 20-25 MPH WITH GUSTS TO 30 MPH WITH MINIMUM RELATIVE
HUMIDITIES NEAR 15-20%. 90
DISCUSSION
A MID/UPPER LEVEL SHORT WAVE IS PRESENT IN BRITISH COLUMBIA,
ALLOWING BREEZY WINDS TO DEVELOP OVER THE NEXT FEW DAYS. DRY AIR
ACROSS THE REGION WILL PERSIST AND, WITH TANDEM TO THE EARLIER
MENTIONED BREEZY WINDS, BRING ELEVATED FIRE WEATHER CONDITIONS
THROUGH AT LEAST THE NEXT FEW DAYS WITH CRITICAL FIRE WEATHER
CONDITIONS DEVELOPING THROUGH 10 PM TONIGHT IN THE COLUMBIA
BASIN IN OREGON.
GUIDANCE AND CLUSTER ANALYSIS IS IN GREAT AGREEMENT (70-90%
CHANCE) THAT THE SHORTWAVE WILL EXIT THE REGION IN THE MONDAY
TIME FRAME AND THE RIDGE THAT IS CURRENTLY SITUATED OVER THE
GREAT PLAINS WILL DOMINANT THE WEATHER PATTERN AND ALLOW A
WARMING TREND TO BEGIN AND PERSIST THROUGH MID-NEXT WEEK. THIS
LOOKS TO PROBABLY BE THE BIGGEST HEAT WAVE SO FAR THIS YEAR WITH
NBM ADVERTISING 50-80% CHANCES OF HIGH TEMPERATURES EXCEEDING
100 DEGREES TUESDAY IN THE POPULATED AREAS IN THE COLUMBIA BASIN
& YAKIMA VALLEY. CHANCES SLIGHTLY DECREASE WEDNESDAY, BUT
CONSIDERABLY DROP DOWN TO 30-50% ON THURSDAY. LOOKING AT
HEATRISK CHANCES, WIDESPREAD MODERATE CHANCES DEVELOP WITH
80-100% CHANCES TUESDAY THROUGH THURSDAY, WITH MAJOR CHANCES OF
HEATRISK AT 40-70%. WILL NEED TO MONITOR OVER THE NEXT FEW DAYS,
BUT IT'S BECOMING LIKELY THAT HEAT HIGHLIGHTS MAY BE WARRANTED
IF TRENDS CONTINUE AS THEY ARE.
THE PATTERN IS LIKELY (50-70% CHANCE) THAT IT WILL BECOME
COOLER AND WETTER GOING INTO THE SECOND PART OF NEXT WEEK WITH A
MID/UPPER LEVEL LOW PUSHING THROUGH THE PACNW AND A TROPICAL
STORM IN THE PACIFIC JUST OFF MEXICO INFLUENCING THE MOISTURE
TRANSPORTATION INTO THE REGION. CHANCES OF SHOWERS (20-40%
CHANCE) DEVELOP ACROSS THE BLUE MOUNTAINS MID-WEEK WITH THE
GREATEST CHANCE OCCURRING THURSDAY.
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
VFR CONDITIONS CURRENTLY ACROSS ALL SITES, WHICH WILL STAY THE
COURSE THROUGH THE PERIOD. HOWEVER, KPDT/KALW/KRDM/KBDN MAY
DROP BRIEFLY TO MVFR DUE TO REDUCED VISIBILITIES CAUSED BY SMOKE
FROM NEARBY WILDFIRES. KDLS/KPDT/KRDM/KBDN WILL ALSO EXPERIENCE
BREEZY WINDS THIS AFTERNOON AS GUSTS OF 18-25KTS ARE EXPECTED.
75
PRELIMINARY POINT TEMPS/POPS
PDT 91 55 91 60 / 0 0 0 0
ALW 93 61 93 64 / 0 0 0 0
PSC 95 57 93 61 / 0 0 0 0
YKM 92 57 94 63 / 0 0 0 0
HRI 93 59 94 62 / 0 0 0 0
ELN 84 54 91 59 / 0 0 0 0
RDM 91 49 93 60 / 0 0 0 0
LGD 94 54 94 59 / 0 0 0 0
GCD 96 54 96 60 / 0 0 0 0
DLS 89 59 96 65 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...RED FLAG WARNING UNTIL 10 PM PDT THIS EVENING FOR WAZ690.
OR...RED FLAG WARNING UNTIL 10 PM PDT THIS EVENING FOR ORZ691.
AIR QUALITY ALERT UNTIL NOON PDT MONDAY FOR ORZ050-502-503-505-
506-508.
UPDATE...90
DISCUSSION...95
AVIATION...75
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