A strong low level jet of 50 to 60 kts developed over southwest Iowa. Elevated convection developed with the strong convergence.
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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 DMX wrote it up.
A strong low level jet of 50 to 60 kts developed over southwest Iowa. Elevated convection developed with the strong convergence. Effective shear was around 40 kts, with 0-1 km shear around 50 kts. The downdraft CAPE was between 1300 and 1500 J/kg. Thunderstorms formed along an old outflow boundary from thunderstorms to the northwest. A line of thunderstorms developed along this outflow boundary. Most of the storms produced 40 to 50 MPH winds. One storm east of the Audubon airport produced winds around 60 MPH. Large healthy tree branches were taken down and shingles were removed from a roof.
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 Des Moines, IA wrote its last area forecast discussion before the first event at Sep 19, 3:07 AM CST, 1 hour 28 minutes earlier.
AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE DES MOINES IA 407 AM CDT THU SEP 19 2013 .SHORT TERM.../TODAY /... ISSUED AT 330 AM CDT THU SEP 19 2013 SCATTERED EARLY MORNING PRECIPITATION ACROSS THE EAST HAS FORMED ALONG NOSE OF LLJ AND EDGE OF CAP. THIS WILL CONTINUE THROUGH THE EARLY MORNING HOURS...THOUGH WILL START TO WEAKEN TOWARDS 12Z. COMPLEX FORECAST FOR TODAY WITH FROPA EXPECTED TO BRING SHOWERS AND THUNDERSTORMS TO MUCH OF THE AREA. BOUNDARY IS CURRENTLY LOCATED FROM WEST CENTRAL MN INTO NORTH EASTERN NE. THIS HAS MOVED LITTLE OVERNIGHT...AND WILL DROP SE ACROSS IOWA TODAY. HOWEVER...MODELS STILL HAVE SOME DISAGREEMENT ON TIMING OF FRONTAL BOUNDARY AND TIMING WILL HAVE LARGE IMPACT ON PRECIPITATION CHANCES AS WELL AS TEMPERATURES. HAVE KEPT FRONT PROGRESSIVE...WITH BOUNDARY THROUGH CENTRAL IOWA THIS AFTERNOON...HOWEVER MODELS CONTINUE TO SLOW PROGRESSION. BEST CHANCES FOR PRECIPITATION WILL BE ACROSS THE SOUTH AND EAST WITH AFTERNOON HEATING AS FRONT APPROACHES. ONGOING PRECIPITATION BEHIND BOUNDARY WILL LIKELY PUSH INTO NORTHWEST EARLY THIS MORNING...THOUGH WILL BE SOMEWHAT LIMITED BY WARM TEMPERATURES ALOFT...WITH 750MB TEMPS AT OR ABOVE 12C. SEVERE POTENTIAL FOR STORMS IS SOMEWHAT LIMITED AS BEST SHEAR REMAINS BEHIND THE FRONT. HOWEVER...SOME SHEAR WILL REMAIN IN PLACE AND CAPE VALUES WILL BE SUFFICIENT...1000-2000 J/KG TO ALLOW FOR THE POTENTIAL FOR SEVERE STORMS. LARGE HAIL AND DAMAGING WINDS WILL BE THE MAIN THREATS. HAVE KEPT TEMPERATURES NEAR GOING...WITH GOOD WARMING AHEAD OF BOUNDARY WITH SOUTHERLY FLOW AND MIXING. HOWEVER...CLOUDS MAY LIMIT THE AMOUNT OF WARMING...AND MAY BE TOO WARM. IN ADDITION...IF BOUNDARY PASSES THROUGH EARLIER WILL SEE COOLER TEMPERATURES BEHIND BOUNDARY THAN GOING. .LONG TERM.../TONIGHT THROUGH WEDNESDAY/... ISSUED AT 330 AM CDT THU SEP 19 2013 THUNDERSTORMS WILL BE ONGOING FOR THE START OF THE FORECAST PERIOD WITH SOME STRONG CONVECTION POSSIBLE VERY EARLY ON. EXPECT TO SEE THE EVENT BECOME MULTI-CELLULAR FAIRLY QUICKLY. PRECIP WILL EXIT THE CWA BY 12Z. COLD FRONT NORTHEAST-SOUTHWEST ACROSS THE STATE AT 00Z WILL PASS TO THE SOUTHEAST BY AROUND 06Z OR SO. COOLER AND DRIER AIR WILL PUSH INTO THE STATE FRI AND SAT. EXPECT THE COLDEST TEMPERATURES TO BE SATURDAY MORNING. WENT FOR 40S ACROSS THE CWA WITH A FEW UPPER 30S IN THE NORTH. GRADUAL WARMING AFTER THAT WITH THE NEXT ROUND OF PRECIPITATION EXPECTED LATE MON INTO TUE...BUT DON'T LOOK FOR THAT TO BE A VERY SIGNIFICANT EVENT. && .AVIATION...19/06Z ISSUED AT 1200 AM CDT THU SEP 19 2013 A COLD FRONT WILL MOVE ACROSS THE TAF LOCATIONS DURING THE TAF PERIOD. THIS WILL OCCUR DURING THE LATE MORNING AND AFTERNOON INTO THE EARLY EVENING. THUNDERSTORMS WILL DEVELOP ALONG THE FRONTAL BOUNDARY AND A FEW STRONG TO SEVERE STORMS ARE EXPECTED. SURFACE FLOW WILL SWITCH FROM SOUTHERLY TO NORTHWEST LATE IN THE TAF PERIOD. && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && SHORT TERM...AWB LONG TERM...MS SEP 13 AVIATION...FAB
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 502 AM CDT THU SEP 19 2013 IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086- 092>097-201100- EMMET-KOSSUTH-WINNEBAGO-WORTH-PALO ALTO-HANCOCK-CERRO GORDO- POCAHONTAS-HUMBOLDT-WRIGHT-FRANKLIN-BUTLER-BREMER-SAC-CALHOUN- WEBSTER-HAMILTON-HARDIN-GRUNDY-BLACK HAWK-CRAWFORD-CARROLL-GREENE- BOONE-STORY-MARSHALL-TAMA-AUDUBON-GUTHRIE-DALLAS-POLK-JASPER- POWESHIEK-CASS-ADAIR-MADISON-WARREN-MARION-MAHASKA-ADAMS-UNION- CLARKE-LUCAS-MONROE-WAPELLO-TAYLOR-RINGGOLD-DECATUR-WAYNE-APPANOOSE- DAVIS- 502 AM CDT THU SEP 19 2013 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...TODAY AND TONIGHT ISOLATED THUNDERSTORMS ARE POSSIBLE THIS MORNING...HOWEVER SEVERE WEATHER IS NOT LIKELY. THUNDERSTORMS WILL DEVELOP OVER WESTERN IOWA THIS MORNING...AND SPREAD EAST AND SOUTH THIS AFTERNOON AND EVENING. THE THUNDERSTORMS WILL END FROM NORTHWEST TO SOUTHEAST TONIGHT. THERE WILL BE A CHANCE FOR SEVERE WEATHER DURING THE LATE AFTERNOON AND EARLY EVENING HOURS. HIGH WINDS AND LARGE HAIL ARE THE MAIN THREATS. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY OTHER MINIMAL CHANCES FOR THUNDERSTORMS ARE IN THE FORECAST FOR WEST OF INTERSTATE 35 WEST MONDAY. SEVERE WEATHER IS NOT ANTICIPATED. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED BRIEFLY LATE THIS AFTERNOON INTO THE EARLY EVENING.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DES MOINES IA 453 AM CDT THU SEP 19 2013 IAZ045-057-058-191030- AUDUBON-CARROLL-GUTHRIE- 453 AM CDT THU SEP 19 2013 ...STRONG THUNDERSTORM CAPABLE OF SMALL HAIL AND STRONG WINDS... AT 448 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A STRONG THUNDERSTORM 28 MILES SOUTHWEST OF CARROLL...MOVING NORTHEAST AT 45 MPH. PEA SIZE HAIL...WINDS GREATER THAN 40 MPH...ARE POSSIBLE WITH THIS STORM. LOCATIONS IMPACTED INCLUDE... MANNING... GRAY... TEMPLETON... HALBUR... DEDHAM... WILLEY... COON RAPIDS... CARROLL... GUSTY WINDS MAY CAUSE SMALL OBJECTS SUCH AS TRASH BINS TO BLOW AROUND. SEEK SHELTER IN A STURDY STRUCTURE UNTIL THIS STORM HAS PASSED. AWB
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DES MOINES IA 524 AM CDT THU SEP 19 2013 IAZ045-046-057>059-070>072-081-191130- ADAIR-ADAMS-AUDUBON-CARROLL-CASS-DALLAS-GREENE-GUTHRIE-MADISON- 524 AM CDT THU SEP 19 2013 ...LINE OF THUNDERSTORMS CAPABLE OF STRONG WINDS AND SMALL HAIL... AT 520 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM 14 MILES SOUTHEAST OF CARROLL TO 24 MILES SOUTHWEST OF ATLANTIC...MOVING NORTHEAST AT 35 MPH. PEA SIZE HAIL...WINDS UP TO 50 MPH...ARE POSSIBLE WITH THESE STORMS. LOCATIONS IMPACTED INCLUDE... ATLANTIC AIRPORT... CARROLL... CARROLL AIRPORT... GLIDDEN... RALSTON... LIDDERDALE... LEWIS... GRISWOLD... BRAYTON... EXIRA... ATLANTIC... COON RAPIDS... LANESBORO... SCRANTON... CUMBERLAND... GUSTY WINDS MAY CAUSE SMALL BRANCHES TO BE BLOWN DOWN...AND LOOSE OBJECTS TO BLOW AROUND. SEEK SHELTER IN A STURDY STRUCTURE UNTIL THESE STORMS HAVE PASSED. AWB
The Des Moines radar (KDMX), 93 km away, was scanning. The volume nearest the first event began at 10:34 UTC.
1 thunderstorm wind. Local standard time, as filed.
Large tree branches were blown down with some shingles removed from a roof.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2013Every state in 2013This day in weather historyWarnings in Iowa, September 2013
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: 468968.