On July 12, 2011 scattered thunderstorms produced very strong winds across portions of northeast Kansas. The worst damage took place across Riley and Pottawatomie Counties where power poles and large structures were destroyed in that area.
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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 TOP wrote it up.
On July 12, 2011 scattered thunderstorms produced very strong winds across portions of northeast Kansas. The worst damage took place across Riley and Pottawatomie Counties where power poles and large structures were destroyed in that area.
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 Topeka, KS wrote its last area forecast discussion before the first event at Jul 12, 2:14 PM CST, 46 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TOPEKA KS 314 PM CDT TUE JUL 12 2011 .DISCUSSION... TONIGHT THROUGH WEDNESDAY AFTERNOON... 19Z WATER VAPOR SHOWS A CLOSED UPPER-LEVEL TROUGH OVER NORTHWEST OKLAHOMA WITH DECENT SOUTHERLY FLOW AT 500 MB STREAMING COOLER AIR UPSTREAM INTO CENTRAL KANSAS. SURFACE ANALYSIS AND VISIBLE SATELLITE SHOW INSTABILITY INCREASING AS DEVELOPING TOWERING CU IS NOTED OVER SOUTH CENTRAL AND SOUTH EAST KANSAS STREAMING NORTHWARD. WEAK FRONTAL BOUNDARY HAS SETTLED OVER NORTHERN MISSOURI WESTWARD INTO NORTHERN KANSAS WHILE AN OUTFLOW BOUNDARY FROM AN MCS OVER NEBRASKA WAS CONTINUING SOUTHEAST INTO MISSOURI. CLOUD COVER SHOULD INCREASE THIS EVENING AS THE UPPER TROUGH APPROACHES FROM THE SOUTHWEST. CHANCE POPS WERE INSERTED THIS EVENING INTO THE OVERNIGHT PERIOD AS TWO SEPARATE LIFTING MECHANISMS COME INTO PLAY. CONVERGENCE ALONG THE FRONTAL BOUNDARY LIFTS NORTHWARD INTO SOUTHERN NEBRASKA WHILE AN UPPER DISTURBANCE SHIFTS OVERHEAD. MOISTURE POOLING ALONG AND AHEAD OF THE BOUNDARY SHOULD INCREASE DEW POINTS INTO THE LOWER 70S...PROVIDING THE ADEQUATE MOISTURE AND ASCENT. HOWEVER...0-6 KM BULK SHEAR APPEARS WEAK AT 20 KTS WHILE STRAIGHT UNIDIRECTIONAL FLOW AND ML CAPE QUITE HIGH TO NEAR 3000 J/KG LATE AFTERNOON SUGGEST MULTI CELL STRUCTURE WITH SUBSTANTIAL UPDRAFTS. THE 15Z EXPERIMENTAL HRRR AND 4KM WRF MODELS ARE ALSO IN AGREEMENT...BEGINNING WITH ISOLATED CONVECTION OVER SOUTH CENTRAL...INCREASING IN COVERAGE LATER THIS EVENING. STRONG WINDS...SMALL HAIL AND HEAVY RAIN APPEAR TO BE THE MAIN THREATS AT THIS TIME. LOWS OVERNIGHT IN THE 70S ARE PROGGED WITH WINDS BECOMING LIGHT TOWARDS THE SOUTHEAST. ON WEDNESDAY AFTERNOON...WEAK UPPER LEVEL FLOW WILL ALLOW THE SHORTWAVE AND ASSOCIATED VORTICITY MAX TO STALL IN THE AREA. CONTINUED CHANCE POPS AT THIS TIME WITH ISOLATED TO SCATTERED MULTI CELL STORMS EXPECTED. A BRIEF RELIEF FROM THE HEAT IS EXPECTED WITH CLOUD COVER AND ANY PRECIPITATION HOLDING TEMPERATURES TO THE LOWER 90S. BOWEN WEDNESDAY NIGHT THROUGH TUESDAY... WEDNESDAY NIGHT AND THURSDAY...A MINOR UPPER LEVEL TROUGH WILL MOVE AROUND THE NORTHERN PERIPHERY OF H5 RIDGE AXIS ACROSS THE SOUTHERN PLAINS. THERE WILL BE ENOUGH ASCENT AHEAD OF THE H5 TROUGH ALONG WITH WEAK ISENTROPIC LIFT TO CONTINUE A CHANCE FOR SHOWERS AND THUNDERSTORMS WEDNESDAY NIGHT INTO THURSDAY MORNING. THE SOUTHERN PLAINS UPPER LEVEL RIDGE WILL BEGIN TO AMPLIFY ACROSS THE CENTRAL PLAINS. AFTERNOON HEATING MAY CAUSE ISOLATED THUNDERSTORMS TO DEVELOP ACROSS THE CWA. I KEPT A SLIGHT CHANCE OF POPS IN THE FORECAST GRIDS FOR THURSDAY AFTERNOON. HIGH TEMPERATURES WILL WARM INTO THE MID TO UPPER 90S. HEAT INDICES WILL BE IN THE 98 TO 103 DEGREE RANGE. FRIDAY THROUGH TUESDAY...WILL BE HOT. THE UPPER LEVEL RIDGE WILL AMPLIFY AND CENTER ITSELF OVER NORTHEAST KS. THE ECMWF MODEL SHOWS THE CENTER OF THE H5 RIDGE AXIS TO HAVE HEIGHTS OF 603 DKM AT 500MB SATURDAY THROUGH TUESDAY. HIGH TEMPERATURES WILL REACH BETWEEN 99 TO 105 DEGREES ACROSS THE CWA. THE EASTERN AND NORTHERN COUNTIES MAY KEEP LOWER TO MID 70 DEW POINTS...WHICH WOULD CAUSE HEAT INDICES TO EXCEED 110 DEGREES EACH AFTERNOON. THE WESTERN AND SOUTHERN COUNTIES MAY MIX DEEP ENOUGH FOR DEW POINTS TO DROP INTO THE MID TO UPPER 60S DURING THE AFTERNOON HOURS. HOWEVER...MID TO UPPER 60S DEW POINTS WHEN COMBINED WITH HIGH TEMPERATURES AROUND 103 DEGREES WOULD CAUSE HEAT INDICES TO BE IN THE 104 TO 108 DEGREE RANGE. EXCESSIVE HEAT WARNINGS OR HEAT ADVISORIES WILL MOST LIKELY BE NEEDED FRIDAY THROUGH TUESDAY. I KEPT POPS THROUGH THIS PERIOD UNDER 14 PERCENT. GARGAN && .AVIATION... PREDOMINANTLY VFR CONDITIONS EXPECTED THROUGH THE ENTIRE TAF PERIOD. TOP/FOE LIGHT WINDS INITIALLY FROM NORTH WILL VARY AND GRADUALLY TURN BACK AROUND TO SOUTHEAST. SCATTERED THUNDERSTORMS ARE EXPECTED IN THE GENERAL VICINITY OF TAF SITES FROM 20Z THROUGH 04Z...BUT DUE TO EXPECTED SCATTERED NATURE HAVE KEPT CB GROUP FOR THE TIME BEING. LOOK TO REMAIN DRY AFTER 06Z BUT THUNDERSTORMS IN SOUTHERN KANSAS MAY KEEP CLOUDS IN THE AREA...PERHAPS FLIRTING WITH MVFR AT TIMES. BARJENBRUCH && .TOP WATCHES/WARNINGS/ADVISORIES... EXCESSIVE HEAT WARNING UNTIL 8 PM CDT THIS EVENING FOR KSZ010>012-022>024-026-035>040-054>056-058-059. HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR KSZ008-009-020-021- 034. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE TOPEKA KS 330 PM CDT TUE JUL 12 2011 KSZ008>012-020>024-026-034>040-054>056-058-059-132030- REPUBLIC-WASHINGTON-MARSHALL-NEMAHA-BROWN-CLOUD-CLAY-RILEY- POTTAWATOMIE-JACKSON-JEFFERSON-OTTAWA-DICKINSON-GEARY-MORRIS- WABAUNSEE-SHAWNEE-DOUGLAS-LYON-OSAGE-FRANKLIN-COFFEY-ANDERSON- 330 PM CDT TUE JUL 12 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL...NORTH CENTRAL AND NORTHEAST KANSAS. .DAY ONE...THIS AFTERNOON AND TONIGHT. SCATTERED THUNDERSTORMS ARE EXPECTED THIS AFTERNOON AND OVERNIGHT. SOME OF THE STRONGER THUNDERSTORMS MAY BE CAPABLE OF STRONG GUSTY WINDS...FREQUENT LIGHTNING AND HEAVY RAIN. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY. THERE IS A CHANCE FOR THUNDERSTORMS WEDNESDAY THROUGH THURSDAY. A HEAT WAVE IS FORECAST TO CONTINUE FROM FRIDAY THROUGH TUESDAY WITH HEAT INDICES FROM 105 TO 110 DEGREES EACH DAY. THE PROLONGED PERIOD OF HEAT COULD BE DANGEROUS FOR THE ELDERLY AND THOSE WITHOUT AIR CONDITIONING. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED THROUGH TONIGHT.
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TOPEKA KS
356 PM CDT TUE JUL 12 2011
KSZ039-122130-
SHAWNEE-
356 PM CDT TUE JUL 12 2011
...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN SHAWNEE COUNTY...
THROUGH 430 PM CDT...A STRONG THUNDERSTORM WILL MOVE NORTHEAST AT 15
MPH ACROSS PORTIONS OF NORTHWESTERN SHAWNEE COUNTY. NATIONAL WEATHER
SERVICE DOPPLER RADAR INDICATED THIS STORM IS CAPABLE OF PRODUCING
PENNY SIZE HAIL...STRONG WINDS OF 40 TO 50 MPH...HEAVY RAIN AND
FREQUENT LIGHTNING. MOTORISTS ALONG INTERSTATE 70 BETWEEN MILE
MARKERS 347 AND 352 COULD ALSO BE AFFECTED.
THE STORM MAY STRENGTHEN OVER THE NEXT SEVERAL MINUTES. BE READY TO
TAKE SHELTER IN CASE A WARNING IS ISSUED.
&&
LAT...LON 3902 9586 3907 9595 3910 9595 3911 9597
3911 9600 3912 9601 3913 9599 3914 9600
3912 9602 3922 9596 3921 9565
TIME...MOT...LOC 2056Z 216DEG 11KT 3914 9586The Topeka radar (KTWX), 82 km away, was scanning. The volume nearest the first event began at 21:00 UTC.
5 thunderstorm wind, 2 hail. Local standard time, as filed.
A trained spotter reported 60 mph winds, with doors to home blown in and a steel patio table overturned.
The top of a wooden barn was destroyed near Leonardville. One foot diameter trees were split off the main tree trunk. Outer sections of windows on the house were ripped-off. Tree branches were wrapped around a swing set.
A west-facing sliding glass patio door was broken.
Five power poles were destroyed on the west side of U.S. Highway 75.
Three large diameter power poles were reported down west of Wheaton.
Two to four inch diameter limbs were broken. A storage shed had a room and two sides damaged.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Kansas in 2011Every state in 2011This day in weather historyWarnings in Kansas, 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: 333088, 333084, 333081, 333085, 333086, 333082, 333087.