Several thunderstorms formed across northeast and east central Kansas on September 7, 2012. Much of the damage was confined to areas of Lyon, Coffey, and Anderson Counties as a bow-echo thunderstorm formed across Lyon County and moved eastward bringing 60+ mph winds and causing damage to trees, power lines, and outbuildings.
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 TOP wrote it up.
Several thunderstorms formed across northeast and east central Kansas on September 7, 2012. Much of the damage was confined to areas of Lyon, Coffey, and Anderson Counties as a bow-echo thunderstorm formed across Lyon County and moved eastward bringing 60+ mph winds and causing damage to trees, power lines, and outbuildings. Aside from the strong wind these storms produced some 1 inch hail.
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 Sep 7, 11:47 AM CST, 47 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TOPEKA KS 1247 PM CDT FRI SEP 7 2012 ...UPDATE TO AVIATION... .SHORT-TERM UPDATE... PERFORMED AN UPDATE TO PRECIP CHANCES...TEMPERATURES AND WINDS TO REFLECT THE OBSERVED TRENDS. SURFACE COLD FRONT APPEARS TO BE TRACKING SLIGHTLY FASTER THAN PREVIOUSLY EXPECTED CURRENTLY SOUTH OF A LINE FROM OLATHE...TO GARNETT TO EUREKA. HIGHS WERE INCREASED A FEW DEGREES BASED ON THE MIXING ALREADY OCCURRING UNDERNEATH THE MOSTLY CLEAR SKIES AND THE SHALLOW NATURE OF THE COLD AIR ADVECTION BEHIND THE BOUNDARY. LIGHT RAIN IS LAGGING BEHIND THE SFC FRONT...PRIMARILY ALONG THE 850 MB FRONT WHERE THE STRONGER MOISTURE CONVERGENCE AND FRONTOGENETICAL FORCING IS OCCURRING. DO EXPECT THIS ACTIVITY TO INCREASE FROM THE WEST AND NORTH PRIMARILY AFTER 18Z INTO THE EARLY EVENING HOURS AS THE SYSTEM SAGS SOUTH AND EAST. ELEVATED INSTABILITY ACROSS THE CWA MAY STILL ALLOW FOR THUNDERSTORMS THRU THE PERIOD. BOWEN && .DISCUSSION... MAIN FOCUS FOR THE SHORT TERM IS ON THE WIDESPREAD PRECIPITATION CHANCES TODAY AND THE USHERING IN OF COOLER CONDITIONS. EARLY THIS MORNING...THE SURFACE LOW WAS SITUATED OVER SOUTHEAST NEBRASKA WITH THE ASSOCIATED COLD FRONT EXTENDING INTO FAR SOUTH CENTRAL NEBRASKA AND NORTHWEST KANSAS. THIS BOUNDARY WILL CONTINUE TO TRACK SOUTHWARD INTO THE AREA...BEING SITUATED ROUGHLY IN THE MIDDLE OF THE CWA FROM NORTHEAST TO CENTRAL KANSAS BY AROUND 12Z...BEFORE EXITING SOUTHEAST OF THE FORECAST AREA BY EARLY AFTERNOON. ALTHOUGH NO PRECIPITATION WAS DEVELOPING ALONG THIS BOUNDARY EARLY THIS MORNING...AS THE FRONT DIPS SOUTHWARD INTO NORTHEASTERN AND CENTRAL KANSAS THROUGH THE MORNING HOURS THERE WILL BE AN INCREASE IN THE AMOUNT OF MOISTURE CONVERGENCE AND AVAILABLE LIFT THAT WILL HELP TO PRODUCE SCATTERED TO WIDESPREAD SHOWERS AND THUNDERSTORMS BY MID TO LATE MORNING ALONG AND BEHIND THE FRONT. THIS ACTIVITY IS EXPECTED TO CONTINUE INTO THE AFTERNOON HOURS...DIMINISHING ACROSS NORTH CENTRAL KANSAS BY EARLY TO MID AFTERNOON AND MOVING SOUTH OF EAST CENTRAL KANSAS LATE AFTERNOON OR EARLY EVENING. WITH VERY LIMITED INSTABILITY TODAY...EXPECT MUCH OF THE ACTIVITY TO REMAIN IN THE FORM OF SHOWERS WITH ISOLATED THUNDERSTORMS POSSIBLE. MODEL SOUNDINGS FOR THE REGION SHOW A VERY MOIST ADIABATIC PROFILE...SO THIS SYSTEM SHOULD BE AN EFFICIENT RAIN-MAKER. QPF AMOUNTS ACROSS THE FORECAST AREA MAY RANGE FROM A FEW TENTHS OF AN INCH ACROSS NORTH CENTRAL KANSAS TO AROUND HALF AN INCH TO THREE-QUARTERS OF AN INCH OVER CENTRAL TO EAST CENTRAL KANSAS. IN ADDITION TO BRINGING SOME MUCH-NEEDED PRECIPITATION TO THE REGION...THIS SYSTEM WILL ALSO BRING A COOL-DOWN WITH TEMPERATURES DROPPING BELOW SEASONAL NORMALS. BREEZY NORTHERLY WINDS ARE EXPECTED BEHIND THE FRONTAL PASSAGE...WITH CAA RESULTING IN AFTERNOON HIGHS TODAY ONLY REACHING INTO THE MIDDLE TO UPPER 70S. SIMILAR TEMPERATURES ARE EXPECTED ONCE AGAIN ON SATURDAY AS AN AREA OF HIGH PRESSURE BUILDS IN ACROSS THE NORTHERN AND CENTRAL PLAINS BEHIND TODAY'S SYSTEM...KEEPING A NORTHERLY FLOW IN PLACE THROUGH THE FIRST HALF OF THE WEEKEND. OVER THE WEEKEND...AN UPPER LEVEL RIDGE WILL BUILD IN OVER THE ROCKY MOUNTAINS AND SHIFT EASTWARD INTO THE CENTRAL CONUS BY SUNDAY. THE EXPANSIVE AREA OF HIGH PRESSURE UNDER THIS RIDGE WILL KEEP CONDITIONS DRY ACROSS THE CENTRAL U.S. THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. AS THE SURFACE HIGH SHIFTS A BIT EASTWARD ON SUNDAY...WINDS WILL START SHIFTING TO THE EAST AND SOUTHEAST AND RESULT IN TEMPERATURES SLOWLY REBOUNDING BACK INTO THE 80S. BY THE BEGINNING OF NEXT WEEK...ANOTHER UPPER LEVEL TROUGH WILL ENTER INTO THE PACIFIC NORTHWEST...TRACKING EASTWARD ACROSS THE NORTHERN ROCKIES AND INTO THE NORTHERN PLAINS BY THE MIDDLE OF NEXT WEEK. WITH THIS APPROACHING SYSTEM...MODELS ARE SHOWING THE TROUGH PUSHING A LOW PRESSURE SYSTEM SOUTHWARD TOWARD THE REGION AND MAY BRING PRECIPITATION TO AREAS OF NEBRASKA AND NORTHERN KANSAS DURING THE TUESDAY NIGHT THROUGH THURSDAY TIMEFRAME. HAVE NOTHING MORE THAN LOW CHANCE POPS IN THE FORECAST AT THIS TIME DUE TO UNCERTAINTY IN THE TIMING AND LOCATION OF ANY POTENTIAL PRECIPITATION. THIS CHANCE FOR PRECIPITATION AND INCREASED CLOUD COVER WILL HELP TO COOL TEMPERATURES SLIGHTLY...WITH HIGHS GENERALLY IN THE UPPER 70S TO LOW/MID 80S FOR THE MIDDLE OF NEXT WEEK. ACH && .AVIATION... A CLUSTER OF -TSRA WILL IMPACT TERMINALS AFTER 18Z AT KMHK AND 19Z AT KTOP/KFOE. MAIN CONCERN IS FREQUENT LIGHTNING...GUSTY SFC WINDS AND A TEMPORARY REDUCTION TO MVFR WITHIN A HEAVIER RAIN BAND. BEHIND THE COLD FRONT GUSTY NORTH WINDS AT 15 TO 20 KTS SUSTAINED WITH PREVAILING GUSTS BLO 30 KTS THROUGH THE AFTERNOON. CONVECTION SHOULD CLEAR OUT BY 00Z WITH WINDS AND CLOUDS GRADUALLY DIMINISHING THRU THE END OF FORECAST PERIOD. BOWEN && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE TOPEKA KS 502 AM CDT FRI SEP 7 2012 KSZ008>012-020>024-026-034>040-054>056-058-059-081015- REPUBLIC-WASHINGTON-MARSHALL-NEMAHA-BROWN-CLOUD-CLAY-RILEY- POTTAWATOMIE-JACKSON-JEFFERSON-OTTAWA-DICKINSON-GEARY-MORRIS- WABAUNSEE-SHAWNEE-DOUGLAS-LYON-OSAGE-FRANKLIN-COFFEY-ANDERSON- 502 AM CDT FRI SEP 7 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL...NORTH CENTRAL AND NORTHEAST KANSAS. .DAY ONE...TODAY AND TONIGHT. ISOLATED THUNDERSTORMS ARE POSSIBLE TODAY...HOWEVER NO SEVERE WEATHER IS EXPECTED. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY. THUNDERSTORM CHANCES RETURN TO NORTH CENTRAL KANSAS TUESDAY NIGHT...AND TO MUCH OF THE REST OF THE OUTLOOK AREA WEDNESDAY AND THURSDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED THROUGH TONIGHT. ACH
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TOPEKA KS
120 PM CDT FRI SEP 7 2012
KSZ037-054-071900-
LYON-MORRIS-
120 PM CDT FRI SEP 7 2012
...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN MORRIS AND NORTHERN
LYON COUNTIES...
THROUGH 200 PM CDT...A THUNDERSTORM WILL MOVE EAST AT 40 MPH ACROSS
PORTIONS OF SOUTHEASTERN MORRIS AND NORTHERN LYON COUNTIES. SOME
LOCATIONS THAT COULD BE AFFECTED INCLUDE AMERICUS...BUSHONG...EMPORIA
AIRPORT...EMPORIA...ALLEN...ADMIRE...NEOSHO RAPIDS AND READING.
MOTORISTS ALONG THE KANSAS TURNPIKE BETWEEN MILE MARKERS 121 AND 153
COULD ALSO BE AFFECTED. MOTORISTS ALONG INTERSTATE 35 BETWEEN MILE
MARKERS 128 AND 143 COULD ALSO BE AFFECTED.
STORM SPOTTERS REPORTED WINDS UP TO 50 MPH IN SOUTHEASTERN MORRIS
COUNTY.
&&
LAT...LON 3834 9636 3852 9636 3852 9649 3868 9648
3873 9595 3833 9595
TIME...MOT...LOC 1820Z 265DEG 35KT 3857 9638The Topeka radar (KTWX), 54 km away, was scanning. The volume nearest the first event began at 18:35 UTC.
12 thunderstorm wind, 2 hail. Local standard time, as filed.
A public photo on WIBW Facebook indicated a large diameter tree, around 12 inches, broke as a result of strong winds from a severe thunderstorm.
An 8 inch tree limb broke near 12th Street and Chestnut in Emporia, Kansas.
A large diameter tree, around four feet in diameter, was downed in Emporia as a result of strong thunderstorm winds.
The ASOS station at the Emporia Airport recorded a 63 mph wind gust associated with a strong thunderstorm that moved through that area.
A driver on Interstate 35 reported 60 mph wind gusts near Emporia.
Numerous small tree limbs were broken as a result of strong thunderstorm wind gusts.
A 6 inch diameter tree branch fell as a result of thunderstorm winds in Burlington.
Lawn furniture was blown off the deck and small tree limbs were broken.
A COOP Observer reported 3 inch tree limbs down as a result of strong winds.
Power lines were down and building damage was reported from Le Roy, Kansas.
Near Colony 2 small out buildings were damaged and a few trees were down near the Intersection of 200 and Delaware.
Tree limbs were down near the intersection of 100 and Delaware.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Kansas in 2012Every state in 2012This day in weather historyWarnings in Kansas, September 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: 413222, 413223, 413251, 413246, 413248, 413226, 413224, 413247, 413211, 413227, 413230, 413212, 413249, 413250.