An unstable airmass with southerly flow moved over the forecast area, and many thunderstorms developed in the evening hours. Some of these storms became severe, and produced hail and lightning.
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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 unstable airmass with southerly flow moved over the forecast area, and many thunderstorms developed in the evening hours. Some of these storms became severe, and produced hail and lightning.
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 May 24, 2:00 PM PST, 5 hours 5 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PORTLAND OR 300 PM PDT SAT MAY 24 2008 .SYNOPSIS...AN UPPER LEVEL LOW PRESSURE SYSTEM CURRENTLY CENTERED OVER NORTHERN CALIFORNIA WILL CONTINUE TO ROTATE MOISTURE INTO OREGON AND SOUTHWEST WASHINGTON TO MAINTAIN AN ACTIVE WEATHER PATTERN OVER THE FORECAST AREA. UNSTABLE AIR AND MOIST SE FLOW WILL SPARK AFTERNOON AND EVENING SHOWERS ACROSS THE FORECAST AREA NEARLY EVERY DAY OVER THE NEXT WEEK WITH SOME THUNDERSTORMS POSSIBLE THIS AFTERNOON AND SUNDAY AFTERNOON. && .SHORT TERM...A BROAD UPPER LEVEL LOW PRESSURE AREA OVER THE WESTERN U.S. IS CENTERED OVER NORTHERN CALIFORNIA THIS AFTERNOON IN EXCELLENT POSITION TO ROTATE MOISTURE AND INSTABILITY NORTH INTO THE FORECAST AREA. MODELS SHOW ELEVATED CONVECTIVE AVAILABLE POTENTIAL WITH LIFTED INDEX BELOW ZERO OF MUCH OF THE INLAND PART OF THE FORECAST AREA THIS AFTERNOON WITH FAVORABLE SOUTHEAST MID LEVEL FLOW AND A THETA-E RIDGE EXTENDING INTO THE EAST PART OF THE FORECAST AREA. SO SHOWERS AND THUNDERSTORMS AREA GOOD PROSPECT THIS AFTERNOON AND EVENING AND ADDED SMALL HAIL TO THE SOUTHEAST PART OF THE FORECAST AREA WHERE MOISTURE IS MOST RICH AND AIR ALOFT COOLEST...THOUGH CAN NOT RULE IT OUT ANY INLAND LOCATIONS. INFRARED AND VISIBLE SATELLITE IMAGERY SHOW CLOUDS DEVELOPING OVER THE PORTIONS OF THE FORECAST AREA ALREADY AS AFTERNOON SUNSHINE STEEPENS LAPSE RATES. THIS LOW LEVEL HEATING WILL CONTINUE INTO THE EVENING DESTABILIZING THE ATMOSPHERE FOR THE CONVECTION. GENERALLY SOUTHEASTERLY MID FLOW ALOFT WILL BRING SHOWERS AND THUNDERSTORMS DEVELOPING EAST TO THE CASCADES THIS AFTERNOON THEN THEY WILL DRIFT W INTO THE VALLEYS IN THE LATE AFTERNOON AND EVENING. NATIONAL WEATHER SERVICE DOPPLER RADAR SHOWS CELLS ALREADY DEVELOPING THIS AFTERNOON OVER THE INLAND PORTIONS OF THE FORECAST AREA FROM THE NORTH TO THE SOUTH. A REPEAT IS WEATHER PATTERN IS EXPECTED ON SUNDAY. MODELS SUGGEST THE SHOWERS WILL BE MAINLY DIURNAL OVER THE HOLIDAY WEEKEND ALTHOUGH SOME SHOWERS COULD BE NOCTURNAL IF AN EMBEDDED SHORT WAVE ROTATES THROUGH THE AREA AT NIGHT. WILLSON .LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS... SYNOPTIC SCALE BLOCKING WILL CONTINUE ALONG THE WEST COAST DURING THE EARLY PART OF THE EXTENDED. MODELS WANT TO MAINTAIN A CLOSED UPPER LOW OFF THE COAST OF NRN CALIFORNIA THROUGH WED NIGHT...WARRANTING THE DECISION TO KEEP AT LEAST CHANCE POPS IN THE CASCADES THROUGH MOST OF NEXT WEEK. WITH THE POSITION OF THE UPPER LOW...AND CONTINUING SOUTHERLY FLOW ALOFT...KEPT A SLIGHT CHANCE OF THUNDER IN THE FORECAST FOR AREAS SOUTH OF THE COLUMBIA RIVER AND EAST OF THE COAST RANGE FOR TUE AFTERNOON AND EVENING. OVERALL...EXPECT CLOUDY DAYS WITH NEAR NORMAL AFTERNOON HIGHS THROUGH MUCH OF NEXT WEEK. DALTON && .AVIATION...VISIBLE SATELLITE IMAGERY AND RADAR INDICATE CONVECTIVE SHOWERS DEVELOPING OVER CASCADES AND EASTERN OREGON. LIGHTING DATA INDICATES NO TSTMS OVER THE AREA AS OF 21Z. HOWEVER...AS UPPER DISTURBANCE MOVES FARTHER W AND DAYTIME HEATING CONTINUES THIS COULD CHANGE. ANY TSTM ACTIVITY MAY PRODUCE BRIEF HEAVY RAIN...SMALL HAIL AND LIGHTING. EXCEPT FOR ISOLATED CONVECTIVE SHOWERS...EXPECT VFR CIGS AND VSBYS TO CONTINUE THROUGH THE LATE EVENING HOURS. KPDX AND APPROACHES...GENLY VFR EXCEPT IN VICINITY OF CONVECTIVE SHOWERS OR TSTMS. UNSTABLE AIRMASS SUPPORTS TSTM DEVELOPMENT THROUGH 03Z...ESPECIALLY EAST AND SOUTH OF KPDX. && .MARINE...RATHER WEAK PRESSURE GRADIENTS REMAIN OVER THE COASTAL WATERS FOR THE COUPLE OF DAYS. SEAS ON A TREND OF SUBSIDING THROUGH THE NEXT 24 HOURS. ONSHORE WINDS MAY BE SLIGHTLY STRONGER ON MON AS PRESSURE GRADIENT INCREASES SOMEWHAT. && .PQR WATCHES/WARNINGS/ADVISORIES... WA/OR...NONE. && .PRELIMINARY POINT POPS (PROBABILITY OF MEASURABLE PRECIPITATION) AST 333233 PDX 555333 SLE 555333 EUG 555333 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.
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE PORTLAND OR 516 AM PDT SAT MAY 24 2008 ORZ001>014-WAZ019>023-039-040-251300- NORTH OREGON COAST-CENTRAL OREGON COAST- COAST RANGE OF NORTHWEST OREGON- CENTRAL COAST RANGE OF WESTERN OREGON-LOWER COLUMBIA- GREATER PORTLAND METRO AREA-CENTRAL WILLAMETTE VALLEY- SOUTH WILLAMETTE VALLEY-WESTERN COLUMBIA RIVER GORGE- NORTHERN OREGON CASCADE FOOTHILLS-NORTHERN OREGON CASCADES- CASCADE FOOTHILLS IN LANE COUNTY-CASCADES IN LANE COUNTY- UPPER HOOD RIVER VALLEY-SOUTH WASHINGTON CASCADES-WILLAPA HILLS- SOUTH WASHINGTON COAST-I-5 CORRIDOR IN COWLITZ COUNTY- GREATER VANCOUVER AREA-SOUTH WASHINGTON CASCADE FOOTHILLS- 516 AM PDT SAT MAY 24 2008 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHWEST OREGON AND SOUTHWEST WASHINGTON. .DAY ONE...TODAY AND TONIGHT NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PORTLAND OR
741 PM PDT SAT MAY 24 2008
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0705 PM HAIL MULTNOMAH FALLS 45.58N 122.12W
05/24/2008 E0.75 INCH MULTNOMAH OR PUBLIC
REPORTED BY MULTNOMAH FALLS EMPLOYEE. SAID HAIL WAS 2 TO
3 INCHES DEEP AT THE VISITORS CENTER.
&&
DKEETONThe national radar mosaic for the moment the first event began.
1 hail. Local standard time, as filed.
This was reported by a Multnomah Falls employee. The hail was reported to be 2 to 3 inches deep.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Oregon in 2008Every state in 2008This day in weather historyWarnings in Oregon, May 2008
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: 107789.