An area of instability developed over Northwest Oregon early Monday morning producing isolated thunderstorms.
Every event with a place to put it. 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 PQR wrote it up.
An area of instability developed over Northwest Oregon early Monday morning producing isolated thunderstorms.
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 Portland, OR wrote its last area forecast discussion before the first event at Jul 25, 1:00 AM PST, 4 hours earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PORTLAND OR 200 AM PDT MON JUL 25 2011 .SYNOPSIS...AN UPPER LEVEL TROUGH PUSHING INTO THE PACIFIC NW TODAY WILL DEEPEN A MARINE LAYER THAT WILL LINGER FOR THE NEXT FEW DAYS. THE TROUGH WILL MOVE E AFTER MID WEEK ALLOWING THE AIR MASS TO DRY OUT AGAIN AS THE LOW LEVEL FLOW TURNS MORE NORTHERLY. && .SHORT TERM...A MOIST AND MARGINALLY UNSTABLE MID LEVEL LAYER... INDICATED BY SOME ACCAS CLOUDS SUNDAY AND SUPPORTED BY THE 00Z SLE SOUNDING...HAS BEGUN TO PRODUCE SOME SHOWERS AND THUNDERSTORMS EARLY THIS MORNING AS THE MARINE LAYER PUSHES IN UNDERNEATH. NAM AND GFS BUFR SOUNDINGS NOT PARTICULARLY IN TUNE WITH THIS UNSTABLE LAYER... ALTHOUGH NAM DOES PICK UP ON SOME MID LEVEL MOISTURE. GIVEN THE SYNOPTIC SETTING AND A COUPLE OF LIGHTING STRIKES ALREADY EARLY THIS MORNING...WILL NEED TO INCLUDE ISOLATED THUNDERSTORMS THIS MORNING IN ADDITION TO SCATTER SHOWERS. 700 MB MOISTURE IN NAM THAT ROUGHLY CORRESPONDS WITH THE CURRENT SHOWERS IS SLOW TO SHIFT E OF THE CASCADE CREST THIS AFTERNOON...SO WILL KEEP A MENTION OF SHOWERS THROUGH THE DAY AS THE UPPER TROUGH AXIS PUSHES ACROSS. W OF THE CASCADES...PRECIPITATION CHANCES SEEM TO REST MORE WITH THE LOW LEVEL MARINE MOISTURE PUSHING IN. WILL KEEP IN A MENTION OF MORNING DRIZZLE OR LIGHT RAIN ALONG THE COAST AND NORTH INTERIOR...THEN A SLIGHT CHANCE FOR SHOWERS THIS AFTERNOON AS MARINE LAYER MIXES SOME. WITH THE UPPER TROUGH LINGERING...THE NEXT COUPLE OF DAYS SEES THE DEEP MARINE LAYER SLOWLY ERODING UP FROM THE S TUE AFTERNOON THROUGH WED AS THE LOW LEVEL FLOW TURNS MORE NORTHERLY. WILL LEAVE IN SOME LOW POPS FOR SHOWERS INTO WED MAINLY ALONG THE COAST...IN THE MOUNTAINS...AND ACROSS THE N WHERE MOISTURE IS THE BEST. TEMPS WILL BE BACK BELOW NORMAL FOR THE NEXT FEW DAYS. .LONG TERM...MADE NO CHANGES...PREVIOUS DISCUSSION FOLLOWS. ENSEMBLES SHOW PRIMARILY ZONAL FLOW FOR THE REMAINDER OF THE WEEK WITH A FEW MEMBERS INDICATING THE POTENTIAL FOR ANOTHER UPPER LEVEL TROUGH NEAR THE COAST NEXT WEEKEND. TEMPERATURES SHOULD SLOWLY REBOUND THE LATTER HALF OF THE WEEK...BUT REMAIN A COUPLE DEGREES BELOW NORMAL. TW && .AVIATION...AN UPPER LEVEL DISTURBANCE WILL MOVE ACROSS THE REGION TODAY AND TONIGHT. THIS WILL INCREASE THE MARINE LAYER AS WELL AS THE ONSHORE FLOW. MVFR CIGS ALREADY ON THE COAST IS MAKING ITS WAY INLAND THIS MORNING. INLAND SITES SHOULD BEGIN TO LIFT BACK TO VFR BY MIDDAY. HOWEVER...COASTAL SITES WILL LIKELY KEEP MVFR CIGS THROUGHOUT THE DAY. ISOLATED THUNDERSTORMS HAVE DEVELOPED OVER THE CASCADES AHEAD OF THE APPROACHING TROUGH. ISOLATED THUNDERSTORMS PROBABLY CONTINUE THROUGH ABOUT 15Z. KPDX AND APPROACHES...MVFR CIGS AROUND 1500 FEET SHOULD AFFECT THE AREA 12Z THROUGH 18Z. THEN EXPECT CONDITIONS IMPROVING DURING THE AFTERNOON. && .MARINE...FAIRLY QUIET MARINE CONDITIONS ARE EXPECTED FOR THE FIRST HALF OF THE UPCOMING WEEK. BUT STRONGER NORTHERLY WINDS ARE LIKELY AFTER MIDWEEK AS THE THERMALLY INDUCED TROUGH ONCE AGAIN STRENGTHENS ALONG THE SOUTH OREGON COAST. THIS WILL ALLOW FOR PERIODS OF SMALL CRAFT WINDS TO DEVELOP TOWARD THE END OF THE WEEK. SEAS WILL ALSO BUILD A BIT IN RESPONSE TO THE INCREASED WINDS...BUT SHOULD REMAIN BELOW 10 FT. && .PQR WATCHES/WARNINGS/ADVISORIES... OR...NONE. WA...NONE. PZ...NONE. && MORE WEATHER INFORMATION ONLINE AT... HTTP://WEATHER.GOV/PORTLAND THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY REFERRED TO AS THE FORECAST AREA.
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PORTLAND OR
520 AM PDT MON JUL 25 2011
ORZ009-011-WAZ019-023-251300-
NORTHERN OREGON CASCADES OR-SOUTH WASHINGTON CASCADES WA-WESTERN
COLUMBIA RIVER GORGE WA-WESTERN COLUMBIA RIVER GORGE OR-
520 AM PDT MON JUL 25 2011
...SIGNIFICANT WEATHER ADVISORY FOR EASTERN MULTNOMAH...SOUTHERN
SKAMANIA AND NORTHWESTERN HOOD RIVER COUNTIES UNTIL 600 AM PDT...
AT 508 AM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM 6 MILES SOUTH OF NORTH BONNEVILLE...OR 9 MILES
SOUTHWEST OF CASCADE LOCKS...MOVING NORTHEAST AT 35 MPH.
HAIL UP TO ONE HALF INCH IN DIAMETER IS EXPECTED WITH THIS STORM...
ALONG WITH HEAVY RAIN.
* LOCATIONS IMPACTED INCLUDE...
STEVENSON AND WYETH...
CARSON...HOME VALLEY AND WYETH...
STABLER...
INDIAN HEAVEN WILDERNESS...
IN WASHINGTON THIS WILL IMPACT STATE ROUTE 14 BETWEEN MILE MARKERS 31
AND 52.
IN OREGON THIS WILL IMPACT INTERSTATE 84 BETWEEN MILE MARKERS 33 AND
52.
LAT...LON 4603 12190 4594 12159 4590 12159 4551 12185
4559 12212
TIME...MOT...LOC 1219Z 203DEG 33KT 4565 12191
WEATHER.GOV/PORTLANDThe Portland,OR radar (KRTX), 33 km away, was scanning. The volume nearest the first event began at 13:00 UTC.
1 thunderstorm wind. Local standard time, as filed.
A thunderstorm moving through Multnomah County produced lightning that hit a tree which fell on power lines causing a power outage to about 1600 customers.
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, July 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: 333923.