An upper level trough brought thunderstorms with gusty winds and locally heavy rainfall during the afternoon and overnight.
Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS PDT wrote it up.
An upper level trough brought thunderstorms with gusty winds and locally heavy rainfall during the afternoon and overnight.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Pendleton, OR wrote its last area forecast discussion before the first event at Aug 28, 9:10 AM PST, 4 hours 16 minutes earlier.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1010 AM PDT SUN AUG 28 2011
.SHORT TERM...UPDATE...THE UPPER LOW RESPONSIBLE FOR LAST NIGHT'S
ISOLATED TO SCATTERED THUNDERSTORMS CONTINUES TO WOBBLE OVER
SOUTHWEST OREGON THIS MORNING. IT IS BEGINNING TO SHOW SIGNS OF THE
START OF THE EXPECTED EASTWARD DRIFT. STILL, THIS EASTWARD MOVEMENT
WILL BE SLOW, WITH THE SYSTEM REACHING NORTHEAST OREGON BY DAYBREAK
MONDAY MORNING. THUS EXPECT ISOLATED TO SCATTERED THUNDERSTORMS TO
DEVELOP ACROSS MUCH OF THE AREA TODAY, PRIMARILY IN THE AFTERNOON.
ISOLATED THUNDERSTORMS OVER THE EASTERN COLUMBIA BASIN AT THE MOMENT
SHOULD DISSIPATE IN THE NEXT HOUR OR SO. SHEAR LOOKS TO BE THE
STRONGEST OVER CROOK, WHEELER AND GRANT COUNTIES THIS AFTERNOON,
THUS COULD SEE SOME SMALL HAIL AND WIND GUSTS TO AROUND 40 MPH.
AREAS OF SMOKE AND HAZE WILL LIFT AND DISSIPATE AS THE AIR MASS,
WHICH IS QUITE UNSTABLE, MIXES LATE THIS MORNING. UPDATES THIS
MORNING WERE TO ADJUST LOCATION OF ISOLATED VERSUS SCATTERED
COVERAGE OF THUNDERSTORMS THIS AFTERNOON AND TONIGHT. ALSO ADDED
MENTION OF ISOLATED THUNDERSTORMS TO THE YAKIMA VALLEY. 90
.LONG TERM...PREVIOUS DISCUSSION...A DEEPENING UPPER LEVEL TROUGH
WILL REMAIN OVER THE PACIFIC NORTHWEST TUESDAY THROUGH THURSDAY. THE
BEST MOISTURE AND LIFT WILL STAY IN CANADA BUT SOME SHOWERS COULD
SPILL OVER THE WASHINGTON CASCADES OR DEVELOP OVER NORTHEAST OREGON.
A MARINE PUSH AND ASSOCIATED COLD FRONT WILL KEEP BREEZY TO WINDY
CONDITIONS IN THE COLUMBIA GORGE...KITTITAS VALLEY AND THE LOWER
COLUMBIA BASIN TUESDAY THROUGH WEDNESDAY. THIS WILL ALSO BRING MUCH
COOLER TEMPERATURES WITH HIGHS ONLY IN THE MID 70S TO LOW 80S ON
WEDNESDAY AND THURSDAY. WEDNESDAY DEWPOINTS WILL DROP AS DRIER AIR
ALOFT MOVES INTO EASTERN WASHINGTON AND OREGON. RADIATIONAL COOLING
FROM CLEAR SKIES...LOW DEWPOINTS AND LIGHTER WINDS ON WEDNESDAY
NIGHT COULD BRING SOME NEAR FREEZING OVERNIGHT TEMPERATURES TO
CENTRAL OREGON.
THURSDAY HIGH PRESSURE WILL BUILD OFFSHORE WHILE THE TROUGH MOVES
EAST. THIS WILL BRING DRIER CONDITIONS AND A SLOW WARMING TREND FOR
FRIDAY AND SATURDAY. TEMPERATURES WILL BE CLOSER TO SEASONAL NORMALS
WITH HIGHS IN THE MID 80S ON SATURDAY.
&&
.AVIATION...18Z TAFS. UPPER LOW MOVING SLOWLY ACROSS THE REGION TODAY.
ALL TAF SITES HAVE THE POTENTIAL TO SEE SHOWERS AND THUNDERSTORMS
THIS AFTERNOON INTO THE EVENING. CEILINGS WILL LOWER TO 040-070 IN
PRECIPITATION. WIND GUSTS 15-30KT POSSIBLE VICINITY THUNDERSTORMS.
UPPER LOW WILL MOVE EAST LATE TONIGHT AND PRECIPITATION WILL
DIMINISH. FAIR WEATHER EXPECTED MONDAY WITH BREEZY WEST WINDS. 94
&&
.FIRE WEATHER...RED FLAG WARNINGS REMAIN IN EFFECT TODAY FOR OREGON
FIRE WEATHER ZONES 610...611...630...631...632...633...634...635 AND
638...AND WASHINGTON FIRE WEATHER ZONES 631 AND 633. A SLOW MOVING
LOW WILL PASS THROUGH THE REGION TODAY TRIGGERING SCATTERED
THUNDERSTORMS WITH ABUNDANT LIGHTNING. STORMS WILL DEVELOP OVER
CENTRAL OREGON EARLY THIS AFTERNOON AND THEN MOVE INTO NORTHEAST
OREGON AND SOUTHEAST WASHINGTON. STORMS WILL DIMINISH ACROSS CENTRAL
OREGON DURING THE EVENING...BUT WILL NOT MOVE COMPLETELY OUT OF THE
AREA UNTIL MONDAY MORNING. TRIMARCO
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 93 60 90 56 / 30 30 0 0
ALW 94 67 90 63 / 30 30 0 0
PSC 96 63 93 58 / 20 20 0 0
YKM 94 58 91 54 / 20 20 0 0
HRI 96 62 92 58 / 20 20 0 0
ELN 95 59 86 60 / 10 20 0 0
RDM 90 50 87 48 / 30 30 0 0
LGD 93 57 88 53 / 30 30 10 0
GCD 91 55 87 51 / 30 30 10 0
DLS 91 62 85 61 / 20 20 0 0
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...RED FLAG WARNING UNTIL 11 PM PDT THIS EVENING
ORZ049-050-502-505-506.
RED FLAG WARNING UNTIL 3 PM PDT THIS AFTERNOON ORZ509.
RED FLAG WARNING FROM NOON TODAY TO 5 AM PDT MONDAY
ORZ041-044-508.
RED FLAG WARNING UNTIL 5 AM PDT MONDAY ORZ042-503-507.
WA...RED FLAG WARNING UNTIL 11 PM PDT THIS EVENING WAZ030.
RED FLAG WARNING FROM NOON TODAY TO 5 AM PDT MONDAY
WAZ024-028-029-521.
&&
THREAT INDEX
TODAY : YELLOW
MONDAY : GREEN
TUESDAY : GREEN
GREEN: NONE OR LIMITED NEED FOR WATCHES, WARNINGS, OR ADVISORIES.
YELLOW: A FEW WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
RED: NUMEROUS WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
90/76/94HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
1057 AM PDT SUN AUG 28 2011
UPDATED DAY ONE FOR THUNDERSTORM COVERAGE
ORZ041-042-044-049-050-502-503-505>509-WAZ024-026>030-520-521-
291415-
EASTERN COLUMBIA RIVER GORGE OF OREGON-NORTH CENTRAL OREGON-
LOWER COLUMBIA BASIN OF OREGON-GRANDE RONDE VALLEY-WALLOWA COUNTY-
NORTHERN BLUE MOUNTAINS OF OREGON-
SOUTHERN BLUE MOUNTAINS OF OREGON-JOHN DAY BASIN-OCHOCO-
JOHN DAY HIGHLANDS-
FOOTHILLS OF THE NORTHERN BLUE MOUNTAINS OF OREGON-
FOOTHILLS OF THE SOUTHERN BLUE MOUNTAINS OF OREGON-
EAST SLOPES OF THE OREGON CASCADES-
EASTERN COLUMBIA RIVER GORGE OF WASHINGTON-KITTITAS VALLEY-
YAKIMA VALLEY-LOWER COLUMBIA BASIN OF WASHINGTON-
FOOTHILLS OF THE BLUE MOUNTAINS OF WASHINGTON-
NORTHWEST BLUE MOUNTAINS OF WASHINGTON-
EAST SLOPES OF THE WASHINGTON CASCADES-SIMCOE HIGHLANDS-
1057 AM PDT SUN AUG 28 2011
THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL AND NORTHEAST OREGON
AS WELL AS SOUTH CENTRAL AND SOUTHEAST WASHINGTON.
.DAY ONE...TODAY AND TONIGHT
THUNDERSTORMS
EAST SLOPES OF THE WASHINGTON CASCADES, SIMCOE HIGHLANDS,
EASTERN COLUMBIA RIVER GORGE OF WASHINGTON, YAKIMA VALLEY,
LOWER COLUMBIA BASIN OF WASHINGTON, EASTERN COLUMBIA RIVER
GORGE OF OREGON, NORTH CENTRAL OREGON, EAST SLOPES OF THE
OREGON CASCADES
RED FLAG WARNING
SIMCOE HIGHLANDS, EASTERN COLUMBIA RIVER GORGE OF WASHINGTON,
YAKIMA VALLEY, LOWER COLUMBIA BASIN OF WASHINGTON, FOOTHILLS
OF THE BLUE MOUNTAINS OF WASHINGTON, NORTHWEST BLUE MOUNTAINS
OF WASHINGTON, EASTERN COLUMBIA RIVER GORGE OF OREGON, NORTH
CENTRAL OREGON, EAST SLOPES OF THE OREGON CASCADES, LOWER
COLUMBIA BASIN OF OREGON, GRANDE RONDE VALLEY, WALLOWA COUNTY,
FOOTHILLS OF THE NORTHERN BLUE MOUNTAINS OF OREGON, NORTHERN
BLUE MOUNTAINS OF OREGON, SOUTHERN BLUE MOUNTAINS OF OREGON,
FOOTHILLS OF THE SOUTHERN BLUE MOUNTAINS OF OREGON, JOHN DAY
BASIN, OCHOCO-JOHN DAY HIGHLANDS
CONTACT YOUR LOCAL FOREST OR LAND MANAGEMENT AGENCY FOR
CURRENT FIRE DANGER CONDITIONS IN YOUR AREA.
AN UPPER LOW OVER SOUTHWEST OREGON WILL DRIFT SLOWLY EAST-NORTHEAST
TO NEAR WALLOWA COUNTY DURING THIS PERIOD. THIS SYSTEM WILL CAUSE
ISOLATED TO SCATTERED THUNDERSTORMS TO DEVELOP OVER MOST OF THE AREA
THIS AFTERNOON. THESE THUNDERSTORMS WILL PERSIST INTO TONIGHT,
THOUGH THE STORMS WILL END DURING THE EVENING ACROSS SOUTH-CENTRAL
WASHINGTON AND NORTH-CENTRAL AND CENTRAL OREGON. SHEAR LOOKS TO BE
STRONGEST ACROSS CROOK, WHEELER AND GRANT COUNTIES WHERE WIND GUSTS
OF 40 TO 45 MPH AND SMALL HAIL WILL BE POSSIBLE. THE STORM
PREDICTION CENTER ALSO INDICATES THAT CONDITIONS IN THIS AREA COULD
RESULT IN A STORM OR TWO PRODUCING DAMAGING WIND GUSTS. ELSEWHERE
WIND GUSTS OF 30 TO 35 MPH WITH SMALL HAIL MAY OCCUR.
THESE STORMS WILL ALSO HAVE THE POTENTIAL TO PRODUCE SIGNIFICANT
AMOUNTS OF LIGHTNING. THE FUELS ACROSS THE AREA ARE DRY, THUS RED
FLAG WARNINGS REMAIN IN EFFECT. FOR FURTHER DETAILS PLEASE REFER TO
NWS PRODUCT PDXRFWPDT.
.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY
THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.
A FEW THUNDERSTORMS MAY LINGER OVER WALLOWA COUNTY MONDAY MORNING,
OTHERWISE AN INCREASING WEST FLOW WILL BRING AN END TO THE THREAT OF
THUNDERSTORMS. WINDS WILL BECOME BREEZY ACROSS THE COLUMBIA BASIN
MONDAY AFTERNOON. GENERALLY FAIR AND DRY CONDITIONS ARE EXPECTED
TUESDAY THROUGH SATURDAY. TEMPERATURES WILL COOL OFF TO BELOW
SEASONAL VALUES BY MID WEEK.
.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION MAY BE REQUIRED.
WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.
GRAPHICAL FORECASTS OF WEATHER HAZARDS OUT TO SEVEN DAYS
ARE DISPLAYED ON THE WORLD WIDE WEB AT:
WWW.WRH.NOAA.GOV/PDT/CURRENTHAZARDS/HWO.HTML
ALL LETTERS IN THE ABOVE URL ARE LOWER CASE.The Portland,OR radar (KRTX), 189 km away, was scanning. The volume nearest the first event began at 22:46 UTC.
1 wildfire, 1 heavy rain, 1 thunderstorm wind. Local standard time, as filed.
The Shadow Lake Fire in the Mt. Washington Wilderness was started by lightning and had burned up to 500 acres at the end of August.
Spotter reported 1 inch of rain fell in 15 minutes.
Thunderstorm winds accompanied by blowing dust which reduced visibility to 200 feet briefly.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Oregon in 2011Every state in 2011This day in weather historyWarnings in Oregon, August 2011
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 329817, 329801, 329804.