A surface low meandered across South Dakota and into central Minnesota through the day of the 11th. The leading warm front lifted northward through Iowa and into southern Minnesota, firmly placing the state within the warm sector.
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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 surface low meandered across South Dakota and into central Minnesota through the day of the 11th. The leading warm front lifted northward through Iowa and into southern Minnesota, firmly placing the state within the warm sector. That evening, storms initiated along/near the cold front in eastern Nebraska, eventually forming a QLCS that progressed into and through the state. While the system was at its peak primarily west of Interstate 35, severe weather was reported as far east as Plainfield, in Bremer County. The majority of reports were related to thunderstorm wind damage, though small hail, including a severe hail report, was reported.
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 Jul 11, 5:47 PM CST, 2 hours 3 minutes earlier.
Area Forecast Discussion National Weather Service Des Moines IA 647 PM CDT Mon Jul 11 2016 .SHORT TERM.../Tonight/ Issued at 344 PM CDT Mon Jul 11 2016 Area of surface low that has developed across ERN SD with an associated cold front extending southward across ERN NE. Outflow boundary across western IA from earlier convection across MN has provided focus for a line of weak storms across the western CWA. This activity may fester for a bit, but is not expected to do much this afternoon with a decent cap in place. More vigorous activity expected to develop further back to the west in vicinity of the cold front where low level convergence is better. Overall CAPE values very strong with deep layer shear values sufficient but still on the low side. Convection expected as mentioned previously to initiate to our west, and then will push eastward this evening into the overnight hours. LLJ to increase this evening, which should allow the severe threat to extend into the late evening/overnight hours. Overall storms expected to merge into a squall line MCS to move through the CWA. Have pushed main area of higher pops later this evening as it should take some time for the storms to push into central IA, with the main activity expected by mid-evening into late evening. Hydro a small concern, freezing levels around 14-15 kft so expect a lot of warm rain processes. Additionally PWATs around 1.9 inches. Limitations will be centered around more progressive storm motions expected and the fact that much of the CWA can take quite a bit of rain with the mature crops. Am concerned somewhat as the boundary stalls out across the south, with the possibility of storm motion becoming more parallel to the boundary which could set up some training storms. Activity not expected to be as vigorous by that time which should help limit flash flood potential as well. .LONG TERM.../Tuesday through Monday/ Issued at 344 PM CDT Mon Jul 11 2016 Main challenges in the period will be focused on convection and temperatures. In the near term tonights convection will shift east southeast early in the period anchored to the next outflow boundary moving south/southwest overnight. What weak convergence remains over the south tomorrow may have enough afternoon instability to re- initiate convection in the afternoon across the south half. Though a south shift in the airmass is expected by Tuesday...surface and deep layer moisture will remain over the southeast half of the forecast area through 00z Wednesday with some northward expansion of this airmass overnight into Wednesday. Thus...PWATs will recover over the south/southeast to about 2 inches between 21z Tuesday and 06z Wednesday. With a lingering sfc/upper level boundary in the region...any lift across the boundary Tuesday night will focus another MCS over northern MO/southern IA late in the day or overnight hours. We are outlooked for excessive rainfall over the southeast half for Day2...with some potential for heavy rainfall over the south Tuesday night/early Wed. Given the current crop coverage and stage of development...even with localized heavy rainfall possible...unless backbuilding occurs with repeated coverage...any water issues should be limited to localized urban runoff. Temperatures will remain very warm with highs in the mid to upper 80s south with lower to mid 80s in the north. By Wednesday morning both the GFS and Euro project another shortwave with a cool front tracking southeast from Minnesota to Central Iowa by 00z Thursday. Last nights 00z and todays 12z Euro is more robust with its surface features Wednesday and even suggests a cold pool developing with a more expansive area of convection through the day. With upper level support from an increasing H500 band of westerlies moving into northern Iowa by 00z Thursday...the Euro lends some support to a more active day on Wednesday with the stronger dynamics that are forecast. The GFS keeps the bulk of the development across the south later in the afternoon/evening and then reorganizes stronger convection through 06z over northern Missouri. The difference between the models is due to the progression of the sfc boundary...with the GFS having the boundary over central Iowa by 18z while the Euro has it over northwest Iowa...roughly 4 to 6 hours slower. Prefer the Euro which is also supported by the GEM. Highs will be warm again prior to the more significant frontal passage with daytime readings in the upper 80s expected south and lower to mid 80s in the north with warm and humid weather once again. The remainder of the period will be highly dependent upon the cooler airmass over the Great Lakes Friday through Sunday...and how quickly return southerly flow can be established over the Plains. While the GFS already brings moisture back Friday night into Saturday...the 00z Euro holds off on convection until later Saturday night and then only over our extreme west. The newer Euro brings some convection in faster by Friday night and then again on Sunday. With some uncertainties in the forecast into the weekend...will continue the trend from previous forecast of warming temperatures and increasing chances for thunder into the weekend. && .AVIATION.../For the 00Z TAFS through 00Z Tuesday evening/ Issued at 640 PM CDT Mon Jul 11 2016 Boundary will come into state tonight with thunderstorms moving east southeast through the area. While conditions will primarily be VFR, there will be MVFR to IFR conditions in and around thunderstorms during the night. Once the boundary moves through, will see ceilings decrease in the morning in northern IA although the will linger in southern IA as boundary stalls out. Surface winds will be southerly this evening but erratic near storms. Winds generally from the southwest or west on Tuesday. && .DMX WATCHES/WARNINGS/ADVISORIES...None. && SHORT TERM...Beerends LONG TERM...REV AVIATION...Cogil
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 700 PM CDT MON JUL 11 2016 IAZ004>007-015>017-023>026-033>037-044>048-057>060-070>073- 081>083-092-093-121100- EMMET-KOSSUTH-WINNEBAGO-WORTH-PALO ALTO-HANCOCK-CERRO GORDO- POCAHONTAS-HUMBOLDT-WRIGHT-FRANKLIN-SAC-CALHOUN-WEBSTER-HAMILTON- HARDIN-CRAWFORD-CARROLL-GREENE-BOONE-STORY-AUDUBON-GUTHRIE-DALLAS- POLK-CASS-ADAIR-MADISON-WARREN-ADAMS-UNION-CLARKE-TAYLOR-RINGGOLD- 700 PM CDT MON JUL 11 2016 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...TONIGHT THUNDERSTORMS ARE EXPECTED TO MOVE ACROSS THE AREA THIS EVENING AND INTO THE OVERNIGHT. A FEW STORMS MAY BE SEVERE WITH DAMAGING WIND GUSTS IN EXCESS OF 60 MPH AND HALF DOLLAR SIZED HAIL. THE STRONGEST STORMS ARE EXPECTED THROUGH MIDNIGHT. LOCALLY HEAVY RAINFALL MAY OCCUR. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY ADDITIONAL THUNDERSTORMS ARE POSSIBLE TUESDAY AND WEDNESDAY WITH A FEW SEVERE STORMS AND LOCALLY HEAVY RAINFALL POSSIBLE. ADDITIONAL THUNDERSTORMS ARE FORECAST FOR NEXT WEEKEND. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED AT TIMES TONIGHT THROUGH WEDNESDAY. IAZ027-028-038-039-049-050-061-062-074-075-084>086-094>097-121100- BUTLER-BREMER-GRUNDY-BLACK HAWK-MARSHALL-TAMA-JASPER-POWESHIEK- MARION-MAHASKA-LUCAS-MONROE-WAPELLO-DECATUR-WAYNE-APPANOOSE-DAVIS- 700 PM CDT MON JUL 11 2016 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...TONIGHT THUNDERSTORMS ARE EXPECTED TO MOVE ACROSS THE AREA OVERNIGHT...GENERALLY AFTER MIDNIGHT. AN ISOLATED SEVERE STORM WILL BE POSSIBLE WITH DAMAGING WINDS OF 60 MPH AND QUARTER HAIL. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY ADDITIONAL THUNDERSTORMS ARE POSSIBLE TUESDAY AND WEDNESDAY WITH A FEW SEVERE STORMS AND LOCALLY HEAVY RAINFALL POSSIBLE. ADDITIONAL THUNDERSTORMS ARE FORECAST FOR NEXT WEEKEND. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED AT TIMES TONIGHT THROUGH WEDNESDAY.
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
813 PM CDT MON JUL 11 2016
IAZ033-120200-
SAC IA-
813 PM CDT MON JUL 11 2016
...STRONG STORM MAY PRODUCE WIND GUSTS TO 50 MPH AND DIME TO
NICKEL SIZE HAIL...
AT 812 PM CDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM
NEAR LAKESIDE...OR 7 MILES SOUTHWEST OF STORM LAKE...MOVING
NORTHEAST AT 25 MPH.
NICKEL SIZE HAIL AND WIND GUSTS UP TO 50 MPH WILL BE POSSIBLE WITH
THIS STORM.
LOCATIONS IMPACTED INCLUDE...
SCHALLER AND NEMAHA.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TO REPORT SEVERE WEATHER...CONTACT YOUR NEAREST LAW ENFORCEMENT
AGENCY. THEY WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE
OFFICE IN DES MOINES .
&&
A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 1000 PM CDT FOR
WEST CENTRAL IOWA.
LAT...LON 4256 9539 4256 9492 4253 9492 4243 9532
4247 9532 4248 9539
TIME...MOT...LOC 0112Z 239DEG 21KT 4256 9527
KOTENBERGThe Omaha radar (KOAX), 93 km away, was scanning. The volume nearest the first event began at 01:50 UTC.
7 thunderstorm wind, 1 hail. Local standard time, as filed.
Trained spotter reported several trees and tree limbs down. Time radar estimated.
Public reported numerous tree limbs down.
Trained spotter reported wind gust of 60 mph.
Trained spotter reported half dollar sized hail.
Public reported large tree limbs downed near intersection of 190th street and Baxter Ave west of Barnum.
Trained spotter reported a few trees and power lines down across Ames. Also a report of a tree on a car on the west side. Time radar estimated.
Public reported 4 to 5 inch diameter tree down via social media. Delayed report and time radar estimated.
Trained spotter reported numerous trees down and uprooted. A large grain bin was pushed several feet onto the railroad tracks. Large trash dumpsters were also tipped over.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2016Every state in 2016This day in weather historyWarnings in Iowa, July 2016
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: 641275, 641276, 641277, 641278, 641279, 641281, 641282, 641283.