A cold front advanced east into the state during the morning of the 26th. The atmosphere had become quite unstable by late morning with surface dewpoints in the low 70s.
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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 cold front advanced east into the state during the morning of the 26th. The atmosphere had become quite unstable by late morning with surface dewpoints in the low 70s. CAPE increased to 4000 J/kg. Downdraft CAPE was around 1200 J/kg with 400 to 600 J/kg in the -10 to -30 C layer of the atmosphere Shear increased to 40 to 50 kts. The LCL was relatively low, around 750 meters. Precipitable water was round 1.5 inches. A narrow area of thunderstorms developed along the cold front. A tornado touched down briefly northwest of Vincent in Webster County. One inch diameter hail and high winds were produced by one storm in the Britt area of Hancock County.
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 Jun 26, 5:50 AM CST, 3 hours 20 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 650 AM CDT WED JUN 26 2013 .SHORT TERM.../TODAY/... ISSUED AT 401 AM CDT WED JUN 26 2013 SHORT WAVE EVIDENT ON WATER VAPOR PUSHING ACROSS CENTRAL IOWA AT 4 AM. MOST OF THE CONVECTION TONIGHT HAS OCCURRED EAST OF OUR FORECAST AREA SO THE SEVERE THUNDERSTORM WATCH WAS LET GO. SOME FESTERING STILL GOING ON HOWEVER OVER EASTERN PORTIONS OF THE FLASH FLOOD WATCH SO I WILL LEAVE THAT AS IS FOR NOW AND WILL RE-EVALUATE BEFORE I LEAVE MY SHIFT WHETHER TO CANCEL OR EXTEND. AT THIS POINT IT IS LOOKING LIKE A CANCELLATION WILL BE IN ORDER. THERE IS ONE CAVEAT HOWEVER...AND THAT IS THAT DYING STORMS MOVING ACROSS WESTERN MN ARE TRENDING SOUTHEAST ON THE SOUTHERN FLANK. THESE MAY BRUSH A PORTION OF NORTH CENTRAL AND NORTHEAST IOWA. HOWEVER SINCE THEY ARE DYING AND ANY REGENERATION WOULD LIKELY OCCUR EAST OF THE AREA...CLOSER TO WHERE THE SHORTWAVE WILL LIKELY BE...I AM NOT LOOKING FOR ANY HEAVY RAIN THREAT AT THIS POINT. IT SHOULD STILL BE A FAIRLY WARM AND MUGGY DAY TODAY. KEPT TEMPS/DEWPOINTS ABOUT LIKE YESTERDAY. .LONG TERM.../TONIGHT THROUGH TUESDAY/... ISSUED AT 401 AM CDT WED JUN 26 2013 THIS PERIOD WILL BE MUCH MORE TRANQUIL THAN THE RECENT PAST...ALTHOUGH THERE ARE STILL A FEW PRECIP WINDOWS OF CONCERN. SHORT WAVE HELPING TO PRODUCE CURRENT NERN IA TORRENTIAL RAINS SHOULD BE WELL EAST OF THE AREA BY 00Z WITH FAIR WEATHER HEADING INTO TONIGHT. ONE OF THE AFOREMENTIONED PRECIP WINDOWS RETURNS AS SOON AS THU HOWEVER. VERY WEAK SHORT WAVE WILL TOP THE WRN CONUS RIDGE WITH MAINLY A THERMODYNAMIC RESPONSE INTO THE MO RIVER VALLEY. QUICK SHOT OF RETURN FLOW WILL BRING ANOTHER SURGE OF INSTABILITY WITH MUCAPES BACK INTO SEVERAL THOUSAND J/KG. ANY CONVECTION WOULD LIKELY BE ELEVATED WITH WEAK SURFACE FLOW NEAR THE RIDGE. 310/315K ISENT SURFACES DEPICT NICE LIFT AND BAROCLINICITY NEAR THE MO RIVER WHICH MAY GET INTO SWRN IA...THUS HAVE RAISED POPS A BIT IN THOSE LOCATIONS. PATTERN WILL THEN AMPLIFY INTO THU NIGHT AND FRI WITH NOTED CHANGE IN AIRMASS SETTING UP STAGNANT WRN CONUS RIDGE/ERN CONUS TROUGH. NEXT PRECIP CHANCES WILL BE AROUND SAT AS SHORT WAVE AXIS ROTATES DOWN MS VALLEY ON BACK SIDE OF ERN GREAT LAKES TROUGH. SYNOPTIC SCALE FORCING IS WEAK WITH THIS FEATURE...BUT INCREASED MOISTURE BELOW 3KM COUPLED WITH LATE JUNE INSOLATION MAY LEAD TO SCATTERED WEAK CONVECTION. SIMILAR BUT WEAKER SIGNAL SOUTHEAST INTO SUNDAY. PATTERN CHANGES LITTLE INTO EARLY NEXT WEEK. TROUGH/RIDGE MOVE LITTLE BUT FLOW WEAKENS SEASONALLY. ALTHOUGH THERE IS SUFFICIENT EVIDENCE FOR LOW POPS AROUND TUE IN THE VICINITY OF THE UPPER TROUGH...THE MAIN WEATHER STORY FROM THE WEEKEND THROUGH THE END OF THE VALID PERIOD WILL LIKELY BE COOLER LESS HUMID TEMPERATURES. HIGHS WILL LIKELY NOT TOP 80 DEGREES WITH RELATIVELY LOW DEWPOINTS AND WEAK SURFACE WINDS. ECMWF AND GFS BOTH SUGGEST GRADUALLY WARMER BACK TO MORE SEASONAL LEVELS BEYOND THE VALID PERIOD HOWEVER. && .AVIATION...26/12Z ISSUED AT 650 AM CDT TUE JUN 25 2013 UPPER LEVEL TROUGH SHIFTING EAST TODAY AS A COLD FRONT PUSHES ACROSS THE TAF LOCATIONS. THERE MAY BE ISOLD THUNDERSTORMS THROUGH 15Z THEN CIGS BECOMING VFR FROM W TO E THROUGH 00Z. SOUTHERLY WINDS BECOMING LIGHT NWRLY AFT 00Z. && .DMX WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH UNTIL 7 AM CDT THIS MORNING FOR BLACK HAWK- BREMER-BUTLER-CERRO GORDO-FRANKLIN-GRUNDY-HANCOCK-HARDIN- MARSHALL-POWESHIEK-TAMA-WINNEBAGO-WORTH. && SHORT TERM...FAB LONG TERM...SMALL AVIATION...FAB
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 615 AM CDT WED JUN 26 2013 IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086- 092>097-271115- 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- 615 AM CDT WED JUN 26 2013 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...TODAY AND TONIGHT THERE MAY BE A FEW BRIEF THUNDERSTORMS EARLY THIS MORNING. SEVERE WEATHER IS NOT ANTICIPATED. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY CHANCES FOR THUNDERSTORMS RETURN TO SOUTHWEST IOWA THURSDAY. A FEW STORMS MAY BE STRONG WITH SMALL HAIL. OTHER LOW CHANCES FOR THUNDERSTORMS ARE IN THE FORECAST AROUND SATURDAY AND AGAIN TUESDAY. SEVERE WEATHER IS NOT ANTICIPATED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED. FAB
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
447 AM CDT WED JUN 26 2013
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0444 AM FLASH FLOOD 5 NNE EVANSDALE 42.53N 92.24W
06/26/2013 BLACK HAWK IA 911 CALL CENTER
WATER OVER DONALD RD NEAR DEWAR
0446 AM FLASH FLOOD 3 W DUNKERTON 42.57N 92.22W
06/26/2013 BLACK HAWK IA 911 CALL CENTER
WATER OVER ROAD. CLOSURE AT DUNKETON AND RAYMOND RD.
&&
SMALLSPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DES MOINES IA 1003 AM CDT WED JUN 26 2013 IAZ016-017-261600- CERRO GORDO-HANCOCK- 1003 AM CDT WED JUN 26 2013 ...THUNDERSTORM CAPABLE OF SMALL HAIL... AT 959 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A STRONG THUNDERSTORM OVER NORTH CENTRAL HANCOCK COUNTY...MOVING SOUTHEAST AT 15 MPH. PEA SIZE HAIL...WINDS GREATER THAN 30 MPH...BRIEF MODERATE DOWNPOURS...ARE POSSIBLE WITH THIS STORM. LOCATIONS IMPACTED INCLUDE... GARNER... VENTURA... KLEMME... 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
The Des Moines radar (KDMX), 158 km away, was scanning. The volume nearest the first event began at 15:10 UTC.
1 thunderstorm wind, 1 hail, 1 tornado, 1 funnel cloud. Local standard time, as filed.
A half mile wide swath of wind damage was reported. A number of 8 inch diameter branches were broken and a large tree was down over the road.
Several reports and pictures of a landspout northwest of Vincent. Tornado moved very slowly southeast.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2013Every state in 2013This day in weather historyThe tornado archive for Iowa, 2013Warnings in Iowa, June 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: 448674, 448673, 448676, 448671.