Storms developed along an old ouflow boundary. Some of the storms produced large hail and a few reports of damaging winds.
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 LSX wrote it up.
Storms developed along an old ouflow boundary. Some of the storms produced large hail and a few reports of damaging winds.
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 St. Louis, MO wrote its last area forecast discussion before the first event at Aug 8, 2:13 PM CST, 3 hours 20 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ST LOUIS MO 313 PM CDT WED AUG 8 2012 .SYNOPSIS... ISSUED AT 133 PM CDT WED AUG 8 2012 AT 500MB A 596DAM HIGH REMAINS CENTERED OVER ARIZONA WITH A RIDGE AXIS EXTENDING NORTH ALONG THE ROCKIES. MEANWHILE...THE TROF OVER THE EAST COAST CONTINUES TO DEEPEN WITH A PARADE OF SHORTWAVES DIVING ACROSS THE CENTER OF THE UNITED STATES IN NORTHWEST FLOW. WEAK NEARLY STATIONARY SURFACE FRONTAL BOUNDARY STRETCHES FROM THE NORTHERN PLAINS SOUTHEAST TO NORTHERN MISSOURI AND THEN EAST INTO THE GREAT LAKES REGION. THIS BOUNDARY ALONG WITH ONE OF THE AFOREMENTIONED SHORTWAVES RESULTED IN AN AREA OF PRECIPITATION DEVELOPING OVERNIGHT AND MAINTAINING ITSELF ACROSS NORTHERN MISSOURI AND SOUTHERN IOWA...AND NORTHERN ILLINOIS. THIS RESULTED IN AN OUTFLOW BOUNDARY SETTLING SOUTH FROM THE OZARKS TO CENTRAL ILLINOIS. DIURNAL INSTABILITY CONTINUES TO INCREASE...ESPECIALLY ALONG AND SOUTH OF INTERSTATE 70 WHERE LESS CLOUD COVER HAS ALLOWED TEMPERATURES TO RISE INTO THE 90S. STRONGER SHORTWAVE NOTED ON THIS MORNINGS UPPER AIR ANALYSIS AND WATER VAPOR SATELLITE IMAGERY IS DIVING SOUTHEAST FROM NEAR SIOUX CITY IOWA TOWARD THE CWA. CVKING && .SHORT TERM... ISSUED AT 133 PM CDT WED AUG 8 2012 (LATE THIS AFTERNOON INTO TONIGHT) ISOLATED TO SCATTERED DIURNAL CONVECTION EXPECTED TO DEVELOP LATE THIS AFTERNOON AND THIS EVENING...PROBABLY FOCUSED ALONG THE OLD OUTFLOW BOUNDARY...WITH CONTINUED TO DEVELOPMENT ACROSS NORTHERN MISSOURI WHERE 20KT LLJ IS FOCUSED. AREA OF LOW PRESSURE TAKING SHAPE ACROSS EASTERN NEBRASKA ALONG THE STALLED FRONTAL BOUNDARY WILL MOVE SOUTHEAST INTO NORTHERN MISSOURI TONIGHT AHEAD OF THE AFOREMENTIONED SHORTWAVE. TRAILING COLD FRONT WILL FOLLOW SUIT AND LIKELY BE JUST ENTERING THE NORTHWEST PORTION OF THE CWA BY DAYBREAK. THUNDERSTORMS HAVE ALREADY DEVELOPED ACROSS ALONG THE MISSOURI RIVER NORTH OF OMAHA AND BELIEVE THESE WILL EXPAND SOUTH ALONG A CONVERGENCE ZONE THAT STRETCHES INTO EASTERN KANSAS. WILL MAINTAIN HIGH CHANCE POPS FOR THIS EVENING AND INTO THE OVERNIGHT AND LET THE EVENING SHIFT INCREASE OR DECREASE THEM BASED ON UPSTREAM CONVECTIVE DEVELOPMENT AND MOVEMENT. CVKING && .LONG TERM... ISSUED AT 312 PM CDT WED AUG 8 2012 (THURSDAY THROUGH WEDNESDAY) SHOWERS AND THUNDERSTORMS WILL BE ONGOING THURSDAY MORNING AS COLD FRONT SLIDES SOUTHEAST THROUGH FORECAST AREA. ACTIVITY WILL BE SCATTERED...SO KEPT JUST CHANCE POPS THROUGH THURSDAY EVENING ...BEFORE COMING TO AN END. WITH DECENT CAPES AND INSTABILITY... COULD SEE SOME ISOLATED SEVERE STORMS...MAINLY EAST OF METRO AREA. AS FOR HIGH TEMPS...WILL DEPEND ON CLOUD COVER AND STORMS. FOR NOW HAVE MID 80S FAR NORTH TO THE LOW 90S ALONG AND SOUTH OF I-70. BY LATE THURSDAY NIGHT...COOLER DRIER AIR TO MAKE ITS WAY INTO THE FORECAST AREA ON BACK SIDE OF SYSTEM...WITH LOWS IN THE LOW TO MID 60S. THEN MUCH COOLER WEATHER IS IN STORE THROUGH THE WEEKEND WITH HIGHS IN THE 80S THROUGH SUNDAY. THE COLDEST NIGHT WILL BE FRIDAY NIGHT AS THE SURFACE RIDGE SETTLES ACROSS THE REGION. LOWS WILL BE IN THE MID TO UPPER 50S. BEYOND THAT TEMPERATURES TO SLOWLY MODERATE AS SURFACE RIDGE MOVES OFF TO THE EAST...BACK UP INTO THE LOW 90S BY TUESDAY AND WEDNESDAY. AS FOR PCPN CHANCES...EXTENDED MODELS HAVE DIFFERING OPINIONS...BUT FEEL THAT A WEAK TROF WILL SLIDE THROUGH THE AREA SUNDAY NIGHT AND MONDAY...SO HAVE LOW CHANCE POPS FOR PORTIONS OF THE FORECAST AREA. BYRD && .AVIATION... ISSUED AT 1204 PM CDT WED AUG 8 2012 AREA OF SHOWERS ACROSS NORTHERN MISSOURI AND WEST CENTRAL ILLINOIS WILL CONTINUE TO SLIDE EAST EARLY THIS AFTERNOON...IMPACTING KUIN. OUTFLOW BOUNDARY FROM THIS RAIN HAS ROUGHLY REACHED I-70 AND COULD BE THE FOCUS FOR ISOLATED TO SCATTERED THUNDERSTORMS THIS AFTERNOON AND EARLY THIS EVENING. COVERAGE AND CONFIDENCE TOO LOW TO INCLUDE INTO TERMINAL FORECAST ATTM. STRONGER SHORTWAVE LOCATED NEAR SIOUX CITY IOWA WILL MOVE SOUTH/SOUTHEAST THIS AFTERNOON AND TONIGHT. CONVECTION EXPECTED TO INITIATE TO OUR WEST THIS EVENING AND MOVE EAST. TEMPOS OR PREDOMINANT MENTION OF PRECIPITATION WILL NEED TO BE ADDED IF THIS OCCURS BASED ON RADAR TRENDS...BUT FOR NOW BELIEVE A PROB30 COVERS THE THREAT OVERNIGHT. SURFACE LOW WILL DROP SOUTH FROM IOWA INTO MISSOURI OVERNIGHT WITH LIGHT AND VARIABLE WINDS EXPECTED. AS LOW MOVES EAST ON THURSDAY WINDS TO BECOME NORTHWEST. EXPECT CONVECTION WILL REFIRE EAST OF THE TERMINALS ON THURSDAY GIVEN FORECAST SPEED OF THE LOW/FRONT. SPECIFICS FOR KSTL... SCT-BKN MID LEVEL DEBRIS CLOUDS CONTINUE TO SPILL SOUTH OVER THE TERMINAL THIS AFTERNOON. INCREASING INSTABILITY AND VICINITY OF OLD OUTFLOW BOUNDARY COULD RESULT IN ISOLATED TO SCATTERED THUNDERSTORMS DEVELOPING THIS AFTERNOON INTO THIS EVENING. BUT CONFIDENCE TO LOW TO PUT INTO THE BODY OF THE FORECAST. BETTER CHANCE OF PRECIPITATION WILL COME OVERNIGHT AS LOW PRESSURE AND SHORTWAVE MOVE TOWARD THE AREA. SOUTHWEST WIND WILL BECOME LIGHT OVERNIGHT AND THEN SHIFT TO THE NORTHWEST BEHIND THE FRONT ON THURSDAY. CVKING && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && WFO LSX
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE ST LOUIS MO 327 PM CDT WED AUG 8 2012 ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027- 034>036-041-042-047>052-059>065-072>075-084-085-099-091200- GREENE IL-MACOUPIN IL-MONTGOMERY IL-BOND IL-FAYETTE IL-CLINTON IL- MARION IL-WASHINGTON IL-RANDOLPH IL-ADAMS IL-BROWN IL-PIKE IL- CALHOUN IL-JERSEY IL-MADISON IL-ST. CLAIR IL-MONROE IL-KNOX MO- LEWIS MO-SHELBY MO-MARION MO-MONROE MO-RALLS MO-PIKE MO-BOONE MO- AUDRAIN MO-MONITEAU MO-COLE MO-OSAGE MO-CALLAWAY MO-MONTGOMERY MO- LINCOLN MO-GASCONADE MO-WARREN MO-ST. CHARLES MO-FRANKLIN MO- ST. LOUIS MO-ST. LOUIS CITY MO-JEFFERSON MO-CRAWFORD MO- WASHINGTON MO-ST. FRANCOIS MO-STE. GENEVIEVE MO-IRON MO- MADISON MO-REYNOLDS MO- 327 PM CDT WED AUG 8 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EASTERN AND CENTRAL MISSOURI AS WELL AS WEST CENTRAL AND SOUTHWEST ILLINOIS. .DAY ONE...TONIGHT THERE IS A CHANCE OF THUNDERSTORMS. A FEW STORMS MAY BE STRONG AND CAPABLE OF PRODUCING WIND GUSTS OF 50 MPH OR GREATER. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY THE CHANCE OF THUNDERSTORMS WILL CONTINUE ON THURSDAY...BEFORE COMING TO AN END THURSDAY EVENING. SOME OF THE STORMS ON THURSDAY AFTERNOON AND EVENING COULD BE SEVERE...CAPABLE OF PRODUCING DAMAGING WINDS AND LARGE HAIL...MAINLY ALONG AND EAST OF MISSISSIPPI RIVER. THERE IS ANOTHER CHANCE OF THUNDERSTORMS ON SUNDAY NIGHT AND MONDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED THROUGH TONIGHT. BYRD
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE ST LOUIS MO 620 PM CDT WED AUG 8 2012 MOZ072-082345- CRAWFORD MO- 620 PM CDT WED AUG 8 2012 ...SIGNIFICANT WEATHER ADVISORY FOR SOUTHERN CRAWFORD COUNTY UNTIL 645 PM CDT... AT 619 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM NEAR CHERRYVILLE...OR 8 MILES SOUTH OF STEELVILLE...MOVING NORTH AT 5 MPH. HAIL UP TO THE SIZE OF NICKELS AND WIND GUSTS UP TO 40 MPH ARE EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN AND FREQUENT DANGEROUS LIGHTNING. LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE... CHERRYVILLE... IF THREATENING WEATHER APPROACHES YOUR AREA...TAKE SHELTER IN A STURDY BUILDING. IN ADDITION...THIS STORM MAY INTENSIFY...SO BE CERTAIN TO MONITOR LOCAL RADIO AND TV STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS... FOR ADDITIONAL INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE. TORRENTIAL RAIN...WHICH MAY FLOOD LOW LYING AREAS SUCH AS DITCHES AND UNDERPASSES...IS ALSO LIKELY. DO NOT DRIVE YOUR VEHICLE ON A FLOODED ROADWAY. CARNEY
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE ST LOUIS MO 628 PM CDT WED AUG 8 2012 MOZ059-072-090000- CRAWFORD MO-GASCONADE MO- 628 PM CDT WED AUG 8 2012 ...SIGNIFICANT WEATHER ADVISORY FOR GASCONADE AND NORTHWESTERN CRAWFORD COUNTIES UNTIL 700 PM CDT... AT 623 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 6 MILES SOUTH OF BELLE...OR 14 MILES SOUTHWEST OF OWENSVILLE...MOVING EAST AT 15 MPH. HAIL UP TO THE SIZE OF NICKELS AND WIND GUSTS UP TO 50 MPH ARE EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN AND FREQUENT DANGEROUS LIGHTNING. LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE... OWENSVILLE... BLAND... IF THREATENING WEATHER APPROACHES YOUR AREA...TAKE SHELTER IN A STURDY BUILDING. IN ADDITION...THIS STORM MAY INTENSIFY...SO BE CERTAIN TO MONITOR LOCAL RADIO AND TV STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS... FOR ADDITIONAL INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE. TORRENTIAL RAIN...WHICH MAY FLOOD LOW LYING AREAS SUCH AS DITCHES AND UNDERPASSES...IS ALSO LIKELY. DO NOT DRIVE YOUR VEHICLE ON A FLOODED ROADWAY. CARNEY
The St Louis radar (KLSX), 96 km away, was scanning. The volume nearest the first event began at 23:32 UTC.
4 hail, 2 thunderstorm wind. Local standard time, as filed.
There were several reports of nickel size hail south of Bland.
Thunderstorm winds blew down a large tree limb.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Missouri in 2012Every state in 2012This day in weather historyWarnings in Missouri, August 2012
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: 411900, 411901, 411902, 411903, 411904, 411905.