Alert archive / Iowa / Severe Thunderstorm Warnings in 2023

Severe Thunderstorm Warning 64, NWS Des Moines, IA

May 7, 2023Boone County, Greene County, Webster County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at May 7, 2023, 2:03 PM CDT for Boone County, Greene County, Webster County, Iowa. It was in force for 26 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, 2023, 2:03 PM CDT (19:03 UTC)
Expired: May 7, 2023, 2:29 PM CDT
In force: 26 min
Issued by: NWS Des Moines, IA
Area: Storm-based polygon
Hail: 1.0 in
Wind: 50.0 mph

Counties Boone County, IA, Greene County, IA, Webster County, IA

The radar

The Des Moines radar (KDMX), 61 km from the middle of the area, began a volume at 19:07 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 nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 7.1 hours before the alert went out and 205 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: 570 J/kg
Mixed-layer CIN: -206 J/kg
Mixed-layer LCL: 1052 m above ground
0-6 km bulk shear: 53 kt
0-1 km storm-relative helicity: 113 m²/s²
0-3 km storm-relative helicity: 263 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.6

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, 12:46 PM CDT, 1 hour 17 minutes earlier.

Area forecast discussion, May 7, 12:46 PM CDT, 1 hour 17 minutes before

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Hazardous weather outlook, May 7, 4:49 AM CDT, 9 hours 14 minutes before

Hazardous Weather Outlook
National Weather Service Des Moines IA
449 AM CDT Sun May 7 2023

IAZ039-050-061-062-074-075-084>086-092>097-081000-
Black Hawk-Tama-Jasper-Poweshiek-Marion-Mahaska-Lucas-Monroe-
Wapello-Taylor-Ringgold-Decatur-Wayne-Appanoose-Davis-
449 AM CDT Sun May 7 2023

This Hazardous Weather Outlook is for portions of central Iowa.

.DAY ONE...Today and tonight

There is an enhanced threat of severe weather late Sunday through
Sunday night. Large hail, damaging winds, and a few tornadoes may
all be possible at times.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

Additional thunderstorm chances are forecast on Monday and at
intervals from Wednesday into next weekend, however, the overall
threat of severe weather appears low at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed late Sunday.

IAZ004>007-015>017-023>028-033>038-044>049-057>060-070>073-
081>083-081000-
Emmet-Kossuth-Winnebago-Worth-Palo Alto-Hancock-Cerro Gordo-
Pocahontas-Humboldt-Wright-Franklin-Butler-Bremer-Sac-Calhoun-
Webster-Hamilton-Hardin-Grundy-Crawford-Carroll-Greene-Boone-
Story-Marshall-Audubon-Guthrie-Dallas-Polk-Cass-Adair-Madison-
Warren-Adams-Union-Clarke-
449 AM CDT Sun May 7 2023

This Hazardous Weather Outlook is for portions of central Iowa.

.DAY ONE...Today and tonight

A Dense Fog Advisory is in effect for the area through mid morning.
Refer to the National Weather Service Web site at
weather.gov/desmoines for more details.

There is an enhanced threat of severe weather late Sunday through
Sunday night. Large hail, damaging winds, and a few tornadoes may
all be possible at times.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

Additional thunderstorm chances are forecast on Monday and at
intervals from Wednesday into next weekend, however, the overall
threat of severe weather appears low at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed late Sunday.

In the hours before

Special weather statement, May 7, 9:21 AM CDT, 4 hours 42 minutes before

Special Weather Statement
National Weather Service Des Moines IA
921 AM CDT Sun May 7 2023

IAZ046-047-058-059-071-072-071530-
Greene-Boone-Guthrie-Dallas-Adair-Madison-
Including the cities of Jefferson, Boone, Guthrie Center, Panora,
Bayard, Casey, Perry, Waukee, Adel, Greenfield, Stuart, Adair,
Fontanelle, Winterset, and Earlham
921 AM CDT Sun May 7 2023

...Scattered Storms Producing Hail This Morning...

Scattered thunderstorms will affect parts of west central into
central Iowa this morning. Through 1030 am, most of the storms
will be found in areas from around Jefferson to Ames, south to
Greenfield and Winterset. A few locations within that area will
experience penny to nickel sized hail and cloud to ground
lightning strikes.

Lee

Special weather statement, May 7, 10:04 AM CDT, 3 hours 59 minutes before

Special Weather Statement
National Weather Service Des Moines IA
1004 AM CDT Sun May 7 2023

IAZ047-048-059-060-071545-
Story IA-Boone IA-Polk IA-Dallas IA-
1004 AM CDT Sun May 7 2023

...A strong thunderstorm will impact portions of northwestern Polk,
Story, southern Boone and northeastern Dallas Counties through 1045
AM CDT...

At 1004 AM CDT, Doppler radar was tracking a strong thunderstorm over
Madrid, or 12 miles south of Boone, moving east at 45 mph.

HAZARD...Nickel size hail.

SOURCE...Radar indicated.

IMPACT...Minor damage to outdoor objects is possible.

This strong thunderstorm will be near...
  Big Creek Lake around 1010 AM CDT.
  Slater around 1015 AM CDT.

Other locations in the path of this storm include Huxley, Iowa State
Center and Nevada.

This includes Interstate 35 between mile markers 98 and 125.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 4171 9388 4197 9409 4220 9358 4220 9324
      4189 9325
TIME...MOT...LOC 1504Z 247DEG 38KT 4188 9386

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...<30 MPH

Lee

Local storm report, May 7, 10:45 AM CDT, 3 hours 18 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
1045 AM CDT SUN MAY 7 2023

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

1040 AM     HAIL             GRIMES                  41.69N 93.80W
05/07/2023  E0.25 INCH       POLK               IA   TRAINED SPOTTER

&&

MP

Local storm report, May 7, 10:49 AM CDT, 3 hours 14 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
1049 AM CDT SUN MAY 7 2023

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

1045 AM     HAIL             POLK CITY               41.77N 93.72W
05/07/2023  E0.25 INCH       POLK               IA   TRAINED SPOTTER

&&

MP

Local storm report, May 7, 1:43 PM CDT, 20 minutes before

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Local storm report, May 7, 1:50 PM CDT, 13 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, 8:01 PM CDT	Special Weather Statement	DMX	Davis	29 min
May 6, 8:33 PM CDT	Special Weather Statement	DMX	Davis	12 min
May 6, 10:41 PM CDT	Dense Fog Advisory	DMX	Adair, Adams, Audubon, Black Hawk, Boone, Bremer and 36 more	12 hr
May 7, 12:40 AM CDT	Severe Thunderstorm Warning	DMX	Davis	50 min
May 7, 8:53 AM CDT	Special Weather Statement	DMX	Greene	37 min
May 7, 10:04 AM CDT	Special Weather Statement	DMX	Story	41 min
May 7, 12:45 PM CDT	Severe Thunderstorm Warning	DMX	Calhoun, Carroll, Crawford, Sac	45 min
May 7, 1:24 PM CDT	Severe Thunderstorm Warning	DMX	Carroll, Greene	51 min
May 7, 2:56 PM CDT	Severe Thunderstorm Warning	DMX	Boone, Hamilton, Hardin, Marshall, Story	49 min
May 7, 3:30 PM CDT	Severe Thunderstorm Warning	DMX	Jasper, Marshall, Story	45 min
May 7, 3:40 PM CDT	Severe Thunderstorm Warning	DMX	Grundy, Hardin, Marshall, Story, Tama	32 min
May 7, 3:49 PM CDT	Severe Thunderstorm Warning	DMX	Tama	26 min
May 7, 3:51 PM CDT	Severe Thunderstorm Warning	DMX	Jasper, Poweshiek	39 min
May 7, 4:15 PM CDT	Severe Thunderstorm Warning	DMX	Jasper, Marshall, Poweshiek, Tama	45 min
May 7, 4:46 PM CDT	Severe Thunderstorm Warning Destructive damage threat	DMX	Poweshiek, Tama	44 min
May 7, 5:01 PM CDT	Severe Thunderstorm Warning	DMX	Jasper, Mahaska, Poweshiek	44 min
May 7, 5:38 PM CDT	Severe Thunderstorm Warning Considerable damage threat	DMX	Mahaska	15 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2023 Every severe thunderstorm warning in 2023

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.