A front trailing low pressure near Hudson Bay generally stalled out across the state, initially across northern Iowa before progressing southward as a cold front later in the day. Storms that initiated near the front in northwest Iowa in the early morning hours slowly strengthened and progressed east southeast through the morning and early afternoon hours, eventually producing golf ball sized…
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 DMX wrote it up.
A front trailing low pressure near Hudson Bay generally stalled out across the state, initially across northern Iowa before progressing southward as a cold front later in the day. Storms that initiated near the front in northwest Iowa in the early morning hours slowly strengthened and progressed east southeast through the morning and early afternoon hours, eventually producing golf ball sized hail and a hand full of damaging wind reports.
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 13, 5:42 AM CST, 5 hours 53 minutes earlier.
Area Forecast Discussion National Weather Service Des Moines IA 642 AM CDT Wed Jul 13 2016 .SHORT TERM.../Today/ Issued at 324 AM CDT Wed Jul 13 2016 Thunderstorm chances and severe weather potential are the challenges for today. Thunderstorms are over far Southeast Iowa and into Missouri and while this activity may clip the far southeast, it will settle southeast of the area. Additional Thunderstorms are currently ongoing over Northwest Kansas and into Central Nebraska near the left exit region of the low level jet. This area of storms may reach Southwest Iowa early this morning. A third area of storms is expected to ignite toward sunrise over the Siouxland in a region of strong theta-e advection and move into the northwest forecast area this morning. Some uncertainty regarding the evolution of storms from there. Storm motions with the northwest activity would be east northeast and could push the activity mainly into Minnesota. Also possible that the morning storms will move into an area of increasing instability over Central and Southern with diurnal heating and become rooted and surface based. Cloud cover is an uncertainty though with blow off cirrus from the western storms and mid level clouds over Southern Iowa. Instability may be realized if clouds linger and impact high temperatures and the cap above 850 mb holds. Increasing 0-3 km theta-e differences near 35 K over the southern half of the state is a strong signal for cold pool development and is in a region of the highest DCAPE values over 1000 J/KG. Certainly damaging winds will be a threat with storms by late morning and into the afternoon. In addition, should high temperatures in the mid to upper 80s be realized today, large and fat CAPE values through the -10C to -30C layer will provide plenty of vertical acceleration for strong updrafts to support large hail and potential for few occurrences of golf ball sized hail or larger. The tornado and QLCS tornado parameters look weak to marginal with a lack of 0-1 km helicity and lower than optimal 0-3 km shear. Therefore any tornado potential will likely be limited to strong updraft induced vertical stretching of localized vorticity that may be tied to outflow boundaries. .LONG TERM.../Tonight through Tuesday/ Issued at 324 AM CDT Wed Jul 13 2016 The focus of the extended forecast remains on chances for thunderstorms this week followed by above normal temperatures next week. Strong to severe thunderstorms will taper from Northwest to Southeast across Iowa this evening. Thunderstorm intensity will wane during the evening hours with the loss of day time heating, thunderstorms propagating away from upper level support and the loss of cold pool shear balance. On Thursday, cooler and drier air will move into the Midwest with a surface high building over Iowa. Highs will be in the 80s with lows in the 60s. Friday is looking like another comfortable day with similar temperatures. A weak shortwave moving through Northwest flow aloft could bring a few showers and thunderstorms across the the Western half of the state. Surface high pressure builds east with Southerly return flow developing over the weekend. Models continuing to show a series of shortwaves moving overhead bringing additional chances for precipitation. Forecast models prog the strongest shortwave moving through Saturday Night and Sunday producing the best chance for precipitation. The heat returns next week with 500mb ridge building into the Plains and Midwest. A leeside surface trough will deepen with Southwest flow developing from the Plains to the Corn Belt. Upon coordination with neighboring offices, have raised temperatures and removed mention of precipitation chances for next week. If model trends continue, will likely need to raise temperatures even further. && .AVIATION.../For the 12Z TAFS through 12Z Thursday morning/ Issued at 642 AM CDT Wed Jul 13 2016 Thunderstorm potential is the primary aviation concern this period. Thunderstorms will be possible through much of today. Strong and gusty winds may occur with the storms. Localized fog this morning will diminish quickly. Southerly winds will become more westerly with frontal passage later today. && .DMX WATCHES/WARNINGS/ADVISORIES... None. && SHORT TERM...Donavon LONG TERM...Angle AVIATION...Donavon
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 405 AM CDT WED JUL 13 2016 IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075- 081>086-092>097-140915- 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- 405 AM CDT WED JUL 13 2016 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...TODAY AND TONIGHT STRONG TO SEVERE THUNDERSTORMS ARE EXPECTED TODAY AND THIS EVENING. DAMAGING WINDS AND LARGE HAIL WILL BE POSSIBLE. LOCALLY HEAVY RAINFALL WILL OCCUR NEAR THE STRONGEST THUNDERSTORMS. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY ADDITIONAL THUNDERSTORMS ARE POSSIBLE FRIDAY AND THIS WEEKEND. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND EVENING.
The Des Moines radar (KDMX), 61 km away, was scanning. The volume nearest the first event began at 17:32 UTC.
4 thunderstorm wind, 1 hail. Local standard time, as filed.
Trained spotter reported oak tree snapped off at its base and other tree damage and branches down in the immediate area. Delayed report and time radar estimated.
Emergency Manager reported widespread tree damage across town, mostly branches and limbs broken off. Numerous areas remained without power as well. Time radar estimated.
Public reported trees down in town. Time radar estimated.
Media reported a semi blown over on Glendale Road. Time radar estimated.
Emergency Manager reported golf ball sized hail.
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: 641284, 641285, 641286, 641287, 641288.