Alert archive / Iowa / Severe Thunderstorm Warnings in 2024

Severe Thunderstorm Warning 56, NWS Des Moines, IA

May 7, 20249 counties in Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at May 7, 2024, 2:26 AM CDT for 9 counties in Iowa. It was in force for 49 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: May 7, 2024, 2:26 AM CDT (07:26 UTC)
Expired: May 7, 2024, 3:15 AM CDT
In force: 49 min
Issued by: NWS Des Moines, IA
Area: Storm-based polygon
Tornado: Possible
Hail: 0.75 in
Wind: 60.0 mph

Counties Davis County, IA, Grundy County, IA, Jasper County, IA, Mahaska County, IA, Marshall County, IA, Monroe County, IA, Poweshiek County, IA, Tama County, IA, Wapello County, IA

The radar

The Des Moines radar (KDMX), 88 km from the middle of the area, began a volume at 07:26 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
May 6, 7:32 PM CDT	Tornado Watch	SPC	7 hr

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 7.4 hours before the alert went out and 182 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 2 J/kg
Mixed-layer CIN: -3 J/kg
Mixed-layer LCL: 1372 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 1 m²/s²
0-3 km storm-relative helicity: 91 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, 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 this severe thunderstorm warning went out at May 7, 2:09 AM CDT, 17 minutes earlier.

Area forecast discussion, May 7, 2:09 AM CDT, 17 minutes before

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Hazardous weather outlook, May 6, 7:39 PM CDT, 6 hours 47 minutes before

Hazardous Weather Outlook
National Weather Service Des Moines IA
739 PM CDT Mon May 6 2024

IAZ023-024-033>036-044>049-057>061-070>075-081>086-092>097-080045-
Pocahontas-Humboldt-Sac-Calhoun-Webster-Hamilton-Crawford-Carroll-
Greene-Boone-Story-Marshall-Audubon-Guthrie-Dallas-Polk-Jasper-
Cass-Adair-Madison-Warren-Marion-Mahaska-Adams-Union-Clarke-Lucas-
Monroe-Wapello-Taylor-Ringgold-Decatur-Wayne-Appanoose-Davis-
739 PM CDT Mon May 6 2024

This Hazardous Weather Outlook is for portions of central Iowa.

.DAY ONE...Tonight

A Tornado Watch is in effect for the area. Please visit the
National Weather Service webstie at weather.gov/desmoines for
additional information.

There is also a slight risk for excessive rainfall, mainly over
the western half of Iowa. Heavy rain could lead to new or renewed
river flooding in some areas, or ponding of water in low lying or
poor drainage areas.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

Thunderstorm chances return to the forecast on Wednesday and
Thursday. There may be a low threat of severe weather on
Wednesday, but this will be better assessed in the coming days.

.SPOTTER INFORMATION STATEMENT...

Spotters may be needed this evening into tonight, especially
across the southwest half of Iowa.

IAZ004>007-015>017-025>028-037>039-050-062-080045-
Emmet-Kossuth-Winnebago-Worth-Palo Alto-Hancock-Cerro Gordo-
Wright-Franklin-Butler-Bremer-Hardin-Grundy-Black Hawk-Tama-
Poweshiek-
739 PM CDT Mon May 6 2024

This Hazardous Weather Outlook is for portions of central Iowa.

.DAY ONE...Tonight

A line of thunderstorms will enter western Iowa this evening and
move eastward across the state into the early overnight hours.
There is a slight to enhanced risk for severe weather over the
southwest half of the state, though the highest chances for
severe weather are over southwest into southern Iowa. The primary
severe weather threat is damaging wind gusts, but a few tornadoes
are also possible.

There is also a slight risk for excessive rainfall, mainly over
the western half of Iowa. Heavy rain could lead to new or renewed
river flooding in some areas, or ponding of water in low lying or
poor drainage areas.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

Thunderstorm chances return to the forecast on Wednesday and
Thursday. There may be a low threat of severe weather on
Wednesday, but this will be better assessed in the coming days.

.SPOTTER INFORMATION STATEMENT...

Spotters may be needed this evening into tonight, especially
across the southwest half of Iowa.

In the hours before

Local storm report, May 6, 10:05 PM CDT, 4 hours 21 minutes before

Preliminary Local Storm Report
National Weather Service Des Moines IA
1005 PM CDT Mon May 6 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0959 PM     Tstm Wnd Gst     1 NNW Audubon           41.73N 94.94W
05/06/2024  M61 MPH          Audubon            IA   Public

            Personal weather station measured gust.

&&

Dodson

Local storm report, May 6, 10:08 PM CDT, 4 hours 18 minutes before

Preliminary Local Storm Report
National Weather Service Des Moines IA
1008 PM CDT Mon May 6 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1004 PM     Tstm Wnd Gst     4 N Manning             41.97N 95.05W
05/06/2024  E65 MPH          Carroll            IA   Public

            Personal weather station.

&&

Dodson

Local storm report, May 6, 10:22 PM CDT, 4 hours 4 minutes before

Preliminary Local Storm Report
National Weather Service Des Moines IA
1022 PM CDT Mon May 6 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1019 PM     Hail             10 E Audubon            41.73N 94.74W
05/06/2024  M0.88 Inch       Audubon            IA   Emergency Mngr

            Emergency manager reported Nickel Sized hail
            at the intersection of Highway 44 and Swift
            Ave.

&&

AJ

Local storm report, May 6, 10:34 PM CDT, 3 hours 52 minutes before

Preliminary Local Storm Report
National Weather Service Des Moines IA
1034 PM CDT Mon May 6 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1030 PM     Hail             3 W Coon Rapids         41.88N 94.74W
05/06/2024  E0.88 Inch       Carroll            IA   Trained Spotter

            Trained spotter reported nickel sized hail
            west of Coon Rapids. Location estimated with
            radar.

&&

AJ

Special weather statement, May 6, 10:50 PM CDT, 3 hours 36 minutes before

Special Weather Statement
National Weather Service Des Moines IA
1050 PM CDT Mon May 6 2024

IAZ046-047-058>060-071>073-082-083-070430-
Boone IA-Guthrie IA-Greene IA-Clarke IA-Adair IA-Polk IA-Union IA-
Madison IA-Dallas IA-Warren IA-
1050 PM CDT Mon May 6 2024

...STRONG THUNDERSTORMS WILL IMPACT WESTERN POLK...SOUTHEASTERN
GREENE...MADISON...NORTHERN UNION...EASTERN GUTHRIE...SOUTHERN
BOONE...NORTHWESTERN CLARKE...DALLAS...EASTERN ADAIR AND WESTERN
WARREN COUNTIES THROUGH 1130 PM CDT...

At 1049 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from 8 miles south of Jefferson to 4 miles northeast
of Stuart to 4 miles south of Creston. Movement was east at 40 mph.

HAZARD...Wind gusts up to 40 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible.

Locations impacted include...
Des Moines, West Des Moines, Ankeny, Urbandale, Johnston, Clive,
Waukee, Boone, Norwalk, Grimes, Creston, Perry, Winterset, Osceola,
Adel, Windsor Heights, Polk City, Saylorville, Madrid, and Ogden.

This includes the following highways...
 Interstate 35 between mile markers 35 and 72.
 Interstate 80 between mile markers 93 and 136.
 Interstate 235 between mile markers 1 and 8.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

A Tornado Watch remains in effect until 300 AM CDT for central, south
central, southwestern and west central Iowa.

&&

LAT...LON 4097 9446 4151 9433 4195 9444 4211 9375
      4194 9370 4186 9370 4186 9367 4163 9360
      4104 9376
TIME...MOT...LOC 0349Z 258DEG 33KT 4190 9435 4153 9425 4099 9436

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH

Curtis

Local storm report, May 7, 1:38 AM CDT, 48 minutes before

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The office that day

Everything else NWS Des Moines, IA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 6, 9:27 PM CDT	Severe Thunderstorm Warning Considerable damage threat	DMX	Adair, Adams, Audubon, Cass, Guthrie, Taylor	48 min
May 6, 9:35 PM CDT	Severe Thunderstorm Warning Considerable damage threat	DMX	Calhoun, Carroll, Crawford, Greene, Sac	40 min
May 6, 9:45 PM CDT	Tornado Warning	DMX	Carroll, Crawford	45 min
May 6, 10:09 PM CDT	Severe Thunderstorm Warning Considerable damage threat	DMX	Adair, Adams, Audubon, Cass, Dallas, Guthrie and 2 more	51 min
May 6, 10:14 PM CDT	Severe Thunderstorm Warning Considerable damage threat	DMX	Calhoun, Carroll, Crawford, Greene, Humboldt, Pocahontas and 2 more	61 min
May 6, 10:26 PM CDT	Tornado Warning	DMX	Calhoun, Carroll, Greene, Webster	49 min
May 6, 10:50 PM CDT	Special Weather Statement	DMX	Boone, Dallas, Madison, Union	40 min
May 7, 12:33 AM CDT	Severe Thunderstorm Warning	DMX	Clarke, Decatur, Lucas, Madison, Warren, Wayne	42 min
May 7, 12:47 AM CDT	Tornado Warning	DMX	Clarke, Decatur, Lucas, Warren	43 min
May 7, 1:21 AM CDT	Tornado Warning	DMX	Jasper, Mahaska, Marion, Polk, Warren	39 min
May 7, 1:26 AM CDT	Severe Thunderstorm Warning	DMX	Appanoose, Davis, Jasper, Lucas, Mahaska, Marion and 6 more	64 min
May 7, 7:37 AM CDT	River Flood Warning	DMX	Polk	59 hr
May 7, 7:37 AM CDT	River Flood Warning	DMX	Polk	32 hr
May 7, 6:33 PM CDT	Severe Thunderstorm Warning	DMX	Dallas, Polk, Story	27 min
May 7, 6:45 PM CDT	Severe Thunderstorm Warning	DMX	Adair, Audubon, Cass, Guthrie	30 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2024 Every severe thunderstorm warning in 2024

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.