049
FXUS66 KPDT 190522
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1022 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 /06Z TAFS THROUGH 06Z MONDAY/
VFR CONDITIONS ARE CURRENTLY EXPECTED ACROSS ALL SITES. HOWEVER,
DUE TO SMOKE FROM NEARBY WILDFIRES, VIRTUALLY ANY SITE COULD
HAVE MVFR CONDITIONS FOR A PERIOD OF TIME.
WINDS HAVE DECREASED ACROSS THE REGION. WHILE SOME GUSTINESS IN
THE 15 TO 20 MPH RANGE IS POSSIBLE FOR THE NEXT COUPLE HOURS,
ALL SITES SHOULD BE 10 KTS OR LESS OVERNIGHT AND THEN WILL
REMAIN 10 KTS OR LESS THROUGH THE TAF PERIOD.
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 61 91 / 0 0 0 0
ALW 61 93 65 94 / 0 0 0 0
PSC 57 93 62 94 / 0 0 0 0
YKM 57 93 63 94 / 0 0 0 0
HRI 59 93 63 93 / 0 0 0 0
ELN 54 90 59 92 / 0 0 0 0
RDM 49 93 60 89 / 0 0 0 10
LGD 54 95 60 93 / 0 0 0 0
GCD 54 96 61 94 / 0 0 0 0
DLS 59 95 65 95 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...AIR QUALITY ALERT UNTIL NOON PDT MONDAY FOR ORZ050-502-503-505-
506-508.
DISCUSSION...90
AVIATION...77
FIRE WEATHER...90
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