A weak surface front across the Ozarks interacted with several upper level disturbances moving across the region. Several rounds of strong to severe storms occurred as a couple of mesoscale convective system were produced.
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 SGF wrote it up.
A weak surface front across the Ozarks interacted with several upper level disturbances moving across the region. Several rounds of strong to severe storms occurred as a couple of mesoscale convective system were produced. As a result, widespread wind damage and very large hail occurred.
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 Springfield, MO wrote its last area forecast discussion before the first event at Aug 18, 2:07 AM CST, 1 hour 58 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPRINGFIELD MO 307 AM CDT THU AUG 18 2011 .DISCUSSION... MAIN FOCUS THIS FORECAST PERIOD WILL BE WITH CONVECTION CHANCES. CONVECTION ONGOING EARLY THIS MORNING FROM EXTREME SOUTHEAST KANSAS AND THE SOUTHWEST CORNER OF MISSOURI INTO CENTRAL OKLAHOMA IN THE VICINITY OF A FRONTAL BOUNDARY. THIS FRONT IS EXPECTED TO BEGIN LIFTING NORTH AS A WARM FRONT TODAY AND SHOULD PUSH INTO CENTRAL MISSOURI BY TONIGHT. LOW LEVEL JET IS EXPECTED TO REALLY STRENGTHEN LATER THIS EVENING AND OVERNIGHT WITH AN UPPER LEVEL SHORTWAVE DROPPING SOUTHEAST WITHIN THE NORTHWEST FLOW REGIME. WHILE THE MAIN FOCUS FOR SEVERE WEATHER WILL REMAIN OUT IN THE CENTRAL AND NORTHERN PLAINS TODAY...IT APPEARS LIKELY THAT A THUNDERSTORM COMPLEX WILL DEVELOP TONIGHT AS THE LOW LEVEL JET REDEVELOPS AND COULD BRING THIS SOUTHEAST INTO MAINLY THE NORTHERN CWA BY 12Z FRI. BULK OF SEVERE RISK WILL LIKELY REMAIN NORTH OF THE AREA BUT MAY NEED TO WATCH FOR STRONG TO SEVERE WIND RISK ASSOCIATED WITH THIS MCS OVER CENTRAL MO TOWARDS DAYBREAK FRIDAY INTO FRIDAY MORNING. DEPENDING ON HOW THE MCS EVOLVES...COULD CAUSE PROBLEMS WITH TEMPERATURE FORECAST FOR FRIDAYS HIGHS. SOUTHWEST CWA WILL PROBABLY SEE THE LEAST INFLUENCE FROM THE MCS AND WITH VERY WARM 850 MB AIR MOVING IN FROM THE SW WILL PROBABLY SEE UPPER 90S IN THE SOUTHWEST CWA. FURTHER NORTHEAST...CLOUDS/PRECIPITATION WILL LIKELY KEEP TEMPERATURES COOLER...BUT SOME AFTERNOON SUN MAY STILL WARM TEMPERATURES A BIT. FOR NOW WILL GO AROUND 90 IN THE NORTHEAST CWA TO TAKE INTO CONSIDERATION FOR POTENTIAL CLEARING IN THE AFTERNOON. TIMING OF THESE SHORTWAVES WITHIN THE QUICK NORTHWEST FLOW ALOFT WILL BE DIFFICULT BUT WILL LIKELY REMAIN UNSETTLED WITH AT LEAST A LOW CHANCE OF RAIN EACH DAY FROM THE WEEKEND ON. AFTER FRIDAY IT APPEARS LIKELY NEARLY NORMAL TEMPERATURES FOR THIS TIME OF YEAR TO SLIGHTLY WARMER. LINDENBERG && .AVIATION... FOR THE 06Z TAFS...VFR EARLY TONIGHT WITH MVFR VIS FOR EARLY IN THE MORNING AROUND SUNRISE FOR A COUPLE HOURS WITH LIGHT FOG AT ALL TERMINALS POSSIBLE. OTHERWISE MOSTLY CLEAR SKIES AND LIGHT EASTERLY WINDS SHIFTING TO SOUTHERLY BY MIDDAY THURSDAY. GRIFFIN && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE SPRINGFIELD MO 748 PM CDT WED AUG 17 2011 KSZ073-097-101-MOZ055>058-066>071-077>083-088>098-101>106-190100- BOURBON-CRAWFORD-CHEROKEE-BENTON-MORGAN-MILLER-MARIES-VERNON- ST. CLAIR-HICKORY-CAMDEN-PULASKI-PHELPS-BARTON-CEDAR-POLK-DALLAS- LACLEDE-TEXAS-DENT-JASPER-DADE-GREENE-WEBSTER-WRIGHT-NEWTON- LAWRENCE-CHRISTIAN-DOUGLAS-HOWELL-SHANNON-MCDONALD-BARRY-STONE- TANEY-OZARK-OREGON- 748 PM CDT WED AUG 17 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF THE MISSOURI OZARKS AND EXTREME SOUTHEAST KANSAS. .DAY ONE...TONIGHT. WEATHER HAZARDS EXPECTED... LIMITED LIGHTNING RISK. DISCUSSION... AN ISOLATED THUNDERSTORM OR TWO WILL BE POSSIBLE OVERNIGHT WITH THE RISK FOR OCCASIONAL LIGHTNING...BRIEF HEAVY DOWNPOURS...AND GUSTY WINDS UP TO 40 MPH. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY. SCATTERED THUNDERSTORMS WILL BE POSSIBLE ACROSS EXTREME SOUTHEAST KANSAS AN PORTIONS OF SOUTHWEST MISSOURI THURSDAY...MAINLY ALONG AND WEST OF THE HIGHWAY 65 CORRIDOR. A FEW SEVERE THUNDERSTORMS CANNOT BE RULED OUT...MAINLY THURSDAY AFTERNOON...WITH DAMAGING WIND GUSTS AND HAIL TO THE SIZE OF QUARTERS POSSIBLE. A THUNDERSTORM COMPLEX IS EXPECTED TO DEVELOP ACROSS PORTIONS OF NEBRASKA AND KANSAS LATE THURSDAY AFTERNOON AND MOVE SOUTHEAST TOWARDS THE OUTLOOK AREA. THIS SYSTEM WILL HAVE THE POTENTIAL TO AFFECT MUCH OF THE OUTLOOK AREA LATE THURSDAY NIGHT INTO FRIDAY. A FEW SEVERE THUNDERSTORMS CANNOT BE RULED OUT WITH THIS SYSTEM WITH DAMAGING WIND GUSTS THE PRIMARY RISK. LOCALLY HEAVY RAINFALL WILL ALSO BE POSSIBLE...LEADING TO A LIMITED FLASH FLOOD RISK ACROSS CENTRAL MISSOURI. A FEW ADDITIONAL ROUNDS OF THUNDERSTORMS WILL BE POSSIBLE AT TIMES DURING THE UPCOMING WEEKEND. HEAT INDEX VALUES IN THE MIDDLE TO UPPER 90S ARE EXPECTED ACROSS MUCH OF THE REGION FOR THE REMAINDER OF THE WEEK. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED THROUGH TONIGHT. && THIS PRODUCT IS NOW AVAILABLE IN GRAPHICAL FORMAT...ALONG WITH OTHER WEATHER...HYDROLOGICAL AND CLIMATE INFORMATION...AT HTTP://WWW.CRH.NOAA.GOV/SGF(ALL LOWERCASE) GRIFFIN
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SPRINGFIELD MO
422 AM CDT THU AUG 18 2011
MOZ101-181000-
MCDONALD MO-
422 AM CDT THU AUG 18 2011
...SIGNIFICANT WEATHER ADVISORY FOR MCDONALD COUNTY UNTIL 500 AM
CDT...
AT 418 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM 5 MILES EAST OF ANDERSON...OR 5 MILES NORTH OF
PINEVILLE...MOVING EAST AT 20 MPH. NICKEL SIZE HAIL...AND WINDS
AROUND 50 MPH ARE EXPECTED WITH THIS STORM.
LOCATIONS IMPACTED INCLUDE ANDERSON...GOODMAN...LANAGAN...PINEVILLE
AND POWELL.
IF YOU ARE IN THE PATH OF THIS STORM...SEEK SHELTER INDOORS AND STAY
AWAY FROM WINDOWS.
LAT...LON 3660 9448 3676 9441 3676 9433 3671 9408
3649 9407
TIME...MOT...LOC 0923Z 290DEG 18KT 3666 9433
TERRYThe Springfield radar (KSGF), 66 km away, was scanning. The volume nearest the first event began at 10:06 UTC.
15 thunderstorm wind, 6 hail. Local standard time, as filed.
A downed tree blocked both lanes of Highway U about three miles east of Butterfield.
A tree was blown down across Highway E.
A wind gust was estimated by ambulance crew and relayed to county law enforcement.
A volunteer weather observer reported 58 mph winds.
A downed tree blocked the road on Highway W.
The wind gust was reported by the Miller County 911 center.
A tree was downed on the Miller and Camden county line.
Power lines were reported down in the western portion of Miller County.
A tree was downed on Highway 42.
A weather observer reported a couple trees blown down.
Law enforcement estimated 60 to 70 mph wind gusts.
Several trees were blown down onto power lines.
The public reported half dollar size hail at the Super Stop gas station.
TV media relayed a public report of golf ball size hail in Freistatt. There was another public report of golf ball size hail on I-44 in the same area.
TV media relayed a report of golf ball size hail in Aurora.
Baseball size hail broke sky lights at the Walmart.
The Fire Chief reported tennis ball size hail.
Several trees were blown down just east of Forsyth.
The fire department estimated 70 mph wind gusts.
A power pole was blown down.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Missouri in 2011Every state in 2011This day in weather historyWarnings in Missouri, 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: 324234, 324235, 324236, 324237, 324239, 324238, 324241, 324240, 324242, 324244, 324243, 324245, 324228, 324229, 324230, 324231, 324232, 324233, 324248, 324246, 324247.