940
FXUS66 KPDT 182030
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
130 PM PDT SAT JUL 18 2026
KEY MESSAGES
1. HOT, DRY AND WINDY CONDITIONS TODAY THROUGH KITTITAS VALLEY AND
LOWER COLUMBIA BASIN OF OREGON
* RED FLAG WARNING THROUGH 10 PM TODAY*
2. DRY AND WARM CONDITIONS WILL CONTINUE THROUGH TUESDAY
3. PATTERN SHIFT MIDWEEK WILL BRING MONSOONAL MOISTURE BACK TO THE
REGION WITH CHANCES OF THUNDERSTORMS
DISCUSSION
CURRENT SATELLITE SHOWS SOME CUMULUS CLOUDS OVER THE WALLOWA VALLEY
CURRENTLY WITH NO OTHER CLOUDS ACROSS THE REGION. HAZY SKIES WILL
PERSIST THROUGH THE DAY FROM THE SURROUNDING FIRES AND AN AIR
ADVISORY IN EFFECT FOR SOUTHEASTERN OR AND WALLOWA VALLEY THROUGH
MONDAY.
AN UPPER LEVEL SHORTWAVE DISTURBANCE IS PASSING OVER THE REGION JUST
TO THE NORTH OF THE AREA TIGHTENING THE GRADIENTS ACROSS THE
CASCADES. BREEZY TO WINDY CONDITIONS EXPECTED THROUGH THE CASCADES
GAPS, AND ALONG THE LOWER COLUMBIA BASIN OF OREGON. WINDS COUPLED
WITH VERY LOW RELATIVE HUMIDITIES, A RED FLAG WARNING HAS BEEN
ISSUED THROUGH 10PM FOR KITTITAS VALLEY AND THE LOW COLUMBIA BASIN
OF OREGON DUE TO LOW HUMIDITIES AND WINDS OF 20-25 MPH GUSTING TO 30
MPH WITH HIGH CONFIDENCE (80-90%). ONCE THE SHORTWAVE PASSES,
SOUTHWEST FLOW WILL RETURN USHERING DRY AND WARM CONDITIONS.
BY WEDNESDAY, MODELS ARE IN DECENT AGREEMENT AND SHOW A SLIGHT
PATTERN SHIFT WITH THE UPPER LEVEL RIDGE SHIFTING TOWARDS THE FOUR
CORNERS AND ADVECTING SOME MONSOONAL MOISTURE UP INTO THE REGION.
CLUSTERS SHOW THE MAIN DIFFERENCE TO BE MAINLY WITH THE AMPLITUDE OF
THE RIDGE. NBM RAW ENSEMBLES SHOW WEDNESDAY TO HAVE 40% CHANCE OF
THUNDERSTORMS THROUGH DESCHUTES AND GRANT COUNTIES AFTER 2 PM.
LOOKING AT SOUNDINGS SHOW CAPE VALUES OVER 350 J/KG, LAPSE RATES 8.5-
9 C/KM, EFFECTIVE BULK SHEAR OF 20-25 KTS AND LIS OF -4 AND PWATS OF
0.05-1.0 INCHES. NBM QPF SHOWS THESE STORMS TO BE MORE ON THE DRIER
SIDE WITH LESS THAN 10% CHANCE OF A WETTING RAIN. WILL CONTINUE TO
MONITOR AS THE EVENT DRAWS CLOSER.
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
FIRE WEATHER
A RED FLAG WARNING HAS BEEN ISSUES FOR KITTITAS VALLEY AND THE
LOWER COLUMBIA BASIN OF OREGON FOR LOW RELATIVE HUMIDITIES AND
BREEZY WINDS THROUGH 10 PM TONIGHT. RELATIVE HUMIDITIES IN
KITTITAS ARE EXPECTED TO REACH AS LOW 15% WITH WINDS OF 20-25
MPH AND GUSTS TO 30 MPH WHILE THE LOWER COLUMBIA BASIN OF OREGON
WILL SEE RELATIVE HUMIDITIES AS LOW AS 17% AND WINDS 10-20
GUSTING TO 30 MPH. WITH THE FIRES ALREADY ON THE GROUND, THIS
CAN LEAD TO ELEVATED FIRE SPREAD AND ANY NEW FIRES WILL SPREAD
QUICKLY. THE NEXT TIMEFRAME OF CONCERN IS WEDNESDAY WHEN THERE
IS A 40% CHANCE OF THUNDERSTORMS MOVING INTO THE REGION.
PRELIMINARY POINT TEMPS/POPS
PDT 55 91 60 92 / 0 0 0 0
ALW 61 93 64 95 / 0 0 0 0
PSC 57 93 61 95 / 0 0 0 0
YKM 57 94 63 95 / 0 0 0 0
HRI 59 94 62 94 / 0 0 0 0
ELN 54 91 59 93 / 0 0 0 0
RDM 49 93 60 91 / 0 0 0 0
LGD 54 94 59 94 / 0 0 0 0
GCD 54 96 60 94 / 0 0 0 0
DLS 59 96 65 96 / 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.
DISCUSSION...90
AVIATION...75
FIRE WEATHER...90
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