042
FXUS66 KPDT 152100
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
200 PM PDT SAT AUG 15 2026
KEY MESSAGES
- ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS TODAY WITH
ABUNDANT LIGHTNING AND GUSTY WINDS, MAINLY OVER EASTERN
OREGON.
- LOWER (<20 PERCENT) CHANCES OF SHOWERS AND THUNDERSTORMS
SUNDAY AND A 20-30 PERCENT CHANCE OF SHOWERS MONDAY WITH A
(<20 PERCENT) CHANCE OF THUNDERSTORMS MAINLY FROM THE BLUE
MOUNTAINS EASTWARD.
- INCREASING WINDS LATER MONDAY INTO TUESDAY.
DISCUSSION
SOUTHWESTERLY FLOW REMAINS OVER THE PACIFIC NORTHWEST. LOW
PRESSURE WILL MOVE FROM NEAR BRITISH COLUMBIA TO WELL OFF THE
OREGON AND CALIFORNIA COASTS BY MONDAY AFTERNOON. THIS WILL
ALLOW FOR A MORE SPLIT FLOW PATTERN TO DEVELOP EARLY NEXT WEEK,
WHICH SHOULD KEEP THINGS DRY. A RIDGE WILL BUILD BACK OVER THE
AREA BY MIDWEEK, WITH A RETURN TO SOUTHWEST OR SOUTH FLOW
POSSIBLE THEREAFTER.
THE SHOWERS AND THUNDERSTORMS THAT AFFECTED PORTIONS OF THE
COLUMBIA AND BLUE MOUNTAIN FOOTHILLS EARLIER HAVE WEAKENED AND
WERE MOVING OUT OF THE AREA. ADDITIONAL SHOWERS AND
THUNDERSTORMS WERE EXPECTED TO DEVELOP MAINLY FROM THE BLUE
MOUNTAINS EASTWARD THIS AFTERNOON. ANY THUNDERSTORMS COULD
CONTAIN GUST WINDS AND ABUNDANT LIGHTNING. A RED FLAG WARNING
REMAINS IN EFFECT FOR MAINLY THE EASTERN OREGON MOUNTAINS
THROUGH THIS EVENING.
THE MODEL GUIDANCE IS IN REASONABLE AGREEMENT THAT THUNDERSTORM
ACTIVITY ON SUNDAY WILL BE SIGNIFICANTLY LESS AND FURTHER EAST.
WHILE ISOLATED ACTIVITY CAN NOT BE RULED OUT, ESPECIALLY OVER
WALLOWA COUNTY, IT DOES NOT APPEAR TO BE WIDESPREAD ENOUGH TO
WARRANT ANY KIND OF ADDITIONAL HEADLINES. ACTIVITY COULD
POSSIBLY BE A BIT HIGHER ON MONDAY, BUT LOOKS TO BE MAINLY OVER
WALLOWA COUNTY.
AS WE GO FROM MONDAY INTO TUESDAY, A SPLIT FLOW DEVELOPS AND
WINDS WILL INCREASE ACROSS THE AREA. THERE WILL BE SOME
GUSTINESS DEVELOPING MONDAY EVENING, BUT THE BETTER CHANCES ARE
TUESDAY AFTERNOON ACROSS THE CASCADE GAPS, KITTITAS VALLEY,
SIMCOE HIGHLANDS, COLUMBIA BASIN AND GORGE. WINDS COULD GUST 20
TO 30 MPH IN THESE AREAS. RH VALUES WILL ALSO DECREASE FROM
MONDAY INTO TUESDAY. NBM PROBABILITIES OF WIND GUSTS >= 25 MPH
ARE >70 PERCENT IN THESE AREAS. HOWEVER, WITH THE EXCEPTION OF
THE KITTITAS VALLEY, NBM PROBABILITIES OF WIND GUSTS >=39 MPH
ARE LESS THAN 40 PERCENT. WILL NEED TO SEE HOW THESE WINDS
EVOLVE OVER THE NEXT FEW DAYS TO SEE IF ANY HEADLINES WILL BE
NEEDED, BUT FIRE WEATHER CONCERNS WILL AT LEAST BE ELEVATED.
THE MIDWEEK PERIOD LOOKS DRY BEFORE THE SOUTH OR SOUTHWEST FLOW
RETURNS AND AN UPPER LOW COMES INTO PLAY AS WELL. ALL OF THESE
FEATURES COULD BRING ADDITIONAL CHANCES OF PRECIPITATION BY THE
END OF THE WEEK.
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
VFR CONDITIONS TO PREVAIL THROUGH A MAJORITY OF THE PERIOD,
WITH MVFR CONDITIONS POSSIBLE THROUGH THE REMAINDER OF THE
MORNING INTO THE EARLY AFTERNOON. AN UPPER WEATHER SYSTEM MOVING
THROUGH THE AREA EARLY THIS MORNING CONTINUES TO PRODUCE
SHOWERS/THUNDERSTORMS THAT ARE IMPACTING SITES PDT/ALW/PSC.
THESE STORMS SHOULD CLEAR OUT FROM PDT AROUND 18Z, THEN CLEAR
ALW/PSC BETWEEN 19Z-20Z. THUNDERSTORMS WILL CONTINUE TO BE
POSSIBLE ALONG THE WA CASCADE EAST SLOPES AND THE BLUE MOUNTAINS
THROUGH THE AFTERNOON AND EVENING. THERE IS A LOW CHANCE (~15%)
OF SHOWER/THUNDERSTORM IMPACTS AT SITES PDT/ALW BETWEEN
21Z-00Z.
WINDS WILL INCREASE TO 12-20KTS WITH GUSTS 20-30KTS AT SITE DLS
THIS AFTERNOON, BECOMING LIGHT AROUND OR AFTER 05Z. BREEZY WINDS
WILL DEVELOP AT SITES RDM/BDN WITH GUSTS UP TO 20KTS THIS
AFTERNOON, BECOMING LIGHT LATE IN THE EVENING HOURS. WINDS WILL
OTHERWISE REMAIN LIGHT THROUGH THE PERIOD AT ALL OTHER SITES.
LAWHORN/82
FIRE WEATHER
RED FLAG WARNINGS REMAIN IN EFFECT THROUGH THIS EVENING FOR FAR
EASTERN OREGON FOR POTENTIAL THUNDERSTORM DEVELOPMENT, WHICH
ALREADY APPEARS TO BE UNDERWAY IN PORTIONS OF WALLOWA COUNTY.
ANY THUNDERSTORMS COULD BRING ABUNDANT LIGHTNING AND WIND.
FOR SUNDAY AND MONDAY, THUNDERSTORMS CHANCES WILL BE LESS (<20
PERCENT) AND MAINLY CONFINED TO THESE SAME AREAS, THOUGH
CHANCES COULD BE A BIT HIGHER ON MONDAY THAN SUNDAY. AT THIS
TIME, THERE ARE NO PLANS TO EXTEND THE RED FLAG WARNING OR ISSUE
ANOTHER ONE FOR SUNDAY DUE TO THE LOWER PROBABILITIES AND MUCH
LESS AREAL COVERAGE. CURRENT THINKING IS NO HEADLINES WILL BE
NEEDED FOR MONDAY EITHER, BUT WILL REEVALUATE THAT WITH EACH
SUBSEQUENT MODEL RUN.
THE NEXT CONCERN THEN BECOMES GUSTY WINDS LATER MONDAY INTO
TUESDAY, WHICH COULD BE IN THE 25 TO 30 MPH RANGE, COUPLED WITH
DECREASING HUMIDITIES. FIRE WEATHER CONCERNS WILL BE ELEVATED,
BUT WILL NEED TO SEE HOW THINGS DO OR DON'T COME TOGETHER FOR
ANY FORE WEATHER HEADLINES.
PRELIMINARY POINT TEMPS/POPS
PDT 87 56 88 58 / 20 0 0 0
ALW 90 62 90 64 / 30 10 0 0
PSC 92 57 93 59 / 20 0 0 0
YKM 89 60 91 61 / 20 10 0 0
HRI 90 60 91 62 / 20 0 0 0
ELN 85 58 86 59 / 20 10 0 0
RDM 85 49 86 52 / 20 10 0 0
LGD 86 54 89 57 / 70 20 10 0
GCD 88 54 91 56 / 40 0 0 0
DLS 90 63 89 62 / 20 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...AIR QUALITY ALERT UNTIL NOON PDT MONDAY FOR WAZ026-522-523.
RED FLAG WARNING UNTIL 9 PM PDT THIS EVENING FOR WAZ692-693.
AIR QUALITY ALERT UNTIL NOON PDT TODAY FOR WAZ027-521.
OR...AIR QUALITY ALERT UNTIL NOON PDT MONDAY FOR ORZ041-503-505-506-
508>511.
RED FLAG WARNING UNTIL 9 PM PDT THIS EVENING FOR ORZ692>695-
699.
DISCUSSION...77
AVIATION...82
FIRE WEATHER...77
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