Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 16, NWS Des Moines, IA

June 18, 2021Mahaska County, Marion County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Jun 18, 2021, 11:05 PM CDT for Mahaska County, Marion County, Iowa. It was in force for 25 min. 8 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Jun 18, 2021, 11:05 PM CDT (04:05 UTC)
Expired
Jun 18, 2021, 11:30 PM CDT
In force
25 min
Issued by
NWS Des Moines, IA
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Mahaska County, IA, Marion County, IA

The radar

The Des Moines radar (KDMX), 76 km from the middle of the area, began a volume at 04:04 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.

What was reported inside it

TimeReportWhereRemark
Jun 18, 11:05 PM CDTTSTM WND DMG2 N Knoxville, IALARGE TREE KNOCKED DOWN. REPORT VIA SOCIAL MEDIA.
Jun 18, 11:06 PM CDTHAIL 1.25Knoxville, IAPUBLIC REPORT VIA MEDIA ON SOCIAL MEDIA.
Jun 18, 11:08 PM CDTHAIL 1.754 Ne Knoxville, IADELAYED REPORT. TIME ESTIMATED FROM RADAR.
Jun 18, 11:09 PM CDTHAIL 22 E Knoxville, IAVIA SOCIAL MEDIA/BROADCAST MEDIA. TIME ESTIMATED FROM RADAR.
Jun 18, 11:10 PM CDTHAIL 2.54 Ese Lake Red Rock, IAREPORT VIA SOCIAL MEDIA.
Jun 18, 11:13 PM CDTHAIL 1.54 Wnw Harvey, IACORRECTS PREVIOUS HAIL REPORT FROM 4 WNW HARVEY. ONE AND A HALF INCH HAIL ONE AND A HALF MILE SOUTH OF RED ROCK DAM. VIA SOCIAL MEDIA.
Jun 18, 11:15 PM CDTHAIL 14 Sw Pella, IAHOWELL STATION CAMP GROUND JUST SOUTH OF RED ROCK.
Jun 18, 11:35 PM CDTHAIL 1.754 Nw Harvey, IANEAR RED ROCK CAMPGROUNDS.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The watch it was issued in

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

IssuedProductOfficeLasted
Jun 18, 10:08 PM CDTSevere Thunderstorm WatchSPC8 hr

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 4.1 hours before the alert went out and 207 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-pSkew-T log-p diagram, Davenport, at 00:00Z on 2021-06-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 4 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Davenport, at 00:00Z on 2021-06-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -15 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
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
4 J/kg
Mixed-layer CIN
-335 J/kg
Mixed-layer LCL
2572 m above ground
0-6 km bulk shear
55 kt
0-1 km storm-relative helicity
-15 m²/s²
0-3 km storm-relative helicity
55 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

213 
WUUS53 KDMX 190405
SVRDMX
IAC123-125-190430-
/O.NEW.KDMX.SV.W.0016.210619T0405Z-210619T0430Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Des Moines IA
1105 PM CDT Fri Jun 18 2021

The National Weather Service in Des Moines  has issued a

* Severe Thunderstorm Warning for...
  Central Marion County in south central Iowa...
  Southwestern Mahaska County in south central Iowa...

* Until 1130 PM CDT.

* At 1104 PM CDT, a severe thunderstorm was located near Knoxville 
  Raceway, or over Knoxville, moving east at 40 mph.

  HAZARD...60 mph wind gusts and quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Hail damage to vehicles is expected. Expect wind damage 
           to roofs, siding, and trees.

* This severe thunderstorm will be near...
  Lake Red Rock around 1110 PM CDT.

Other locations in the path of this severe thunderstorm include
Pella.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4122 9277 4123 9322 4141 9325 4151 9290
      4151 9286
TIME...MOT...LOC 0404Z 259DEG 34KT 4134 9314 

HAIL...1.00IN
WIND...60MPH
 
$$

Martin
2 follow-up statements
849 
WWUS53 KDMX 190412 RRA
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
1112 PM CDT Fri Jun 18 2021

IAC123-125-190430-
/O.CON.KDMX.SV.W.0016.000000T0000Z-210619T0430Z/
Marion IA-Mahaska IA-
1112 PM CDT Fri Jun 18 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1130 PM CDT
FOR EASTERN MARION AND SOUTHWESTERN MAHASKA COUNTIES...

At 1112 PM CDT, a severe thunderstorm was located over Lake Red Rock,
or near Knoxville, moving east at 40 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect wind damage to 
         roofs, siding, and trees.

This severe storm will be near...
  Pella around 1125 PM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4122 9277 4123 9312 4138 9316 4151 9290
      4151 9286
TIME...MOT...LOC 0412Z 259DEG 34KT 4136 9303 

HAIL...1.00IN
WIND...60MPH
 
$$

Curtis
028 
WWUS53 KDMX 190424
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
1124 PM CDT Fri Jun 18 2021

IAC123-125-190430-
/O.CON.KDMX.SV.W.0016.000000T0000Z-210619T0430Z/
Marion IA-Mahaska IA-
1124 PM CDT Fri Jun 18 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1130 PM CDT
FOR NORTHEASTERN MARION AND WEST CENTRAL MAHASKA COUNTIES...

At 1124 PM CDT, a severe thunderstorm was located over Pella, moving
east at 40 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect wind damage to 
         roofs, siding, and trees.

This severe thunderstorm will remain over mainly rural areas of
northeastern Marion and west central Mahaska Counties, including the
following locations... Harvey and Pella Municipal Airport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4128 9279 4124 9296 4140 9302 4144 9297
      4147 9285 4145 9284
TIME...MOT...LOC 0424Z 259DEG 34KT 4138 9287 

HAIL...1.00IN
WIND...60MPH
 
$$

Curtis

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 18, 9:56 PM CDTSevere Thunderstorm WarningDMXClarke, Lucas, Madison, Marion, Warren49 min
Jun 18, 10:06 PM CDTSevere Thunderstorm WarningDMXAdair, Clarke, Madison, Union39 min
Jun 18, 10:39 PM CDTSevere Thunderstorm WarningDMXLucas, Monroe, Wayne51 min
Jun 18, 10:43 PM CDTSevere Thunderstorm WarningDMXClarke, Lucas, Madison, Union, Warren47 min
Jun 18, 10:45 PM CDTSevere Thunderstorm WarningDMXMahaska, Marion, Monroe, Wapello45 min
Jun 18, 10:54 PM CDTSevere Thunderstorm WarningDMXAdair, Cass51 min
Jun 18, 11:10 PM CDTSevere Thunderstorm WarningDMXAppanoose, Lucas, Monroe, Wayne50 min
Jun 18, 11:14 PM CDTSevere Thunderstorm WarningDMXAdair, Madison46 min
Jun 18, 11:19 PM CDTSevere Thunderstorm WarningDMXMahaska26 min
Jun 18, 11:22 PM CDTSevere Thunderstorm WarningDMXAppanoose, Davis, Monroe, Wapello53 min
Jun 18, 11:25 PM CDTSevere Thunderstorm WarningDMXClarke, Decatur, Lucas, Wayne50 min
Jun 18, 11:32 PM CDTSevere Thunderstorm WarningDMXCass28 min
Jun 18, 11:37 PM CDTSevere Thunderstorm WarningDMXAdair, Adams, Union53 min
Jun 18, 11:54 PM CDTSevere Thunderstorm WarningDMXClarke, Madison, Warren36 min
Jun 18, 11:55 PM CDTSevere Thunderstorm WarningDMXAppanoose, Lucas, Monroe, Wayne50 min
Jun 18, 11:59 PM CDTSevere Thunderstorm WarningDMXAdair, Adams, Clarke, Madison, Ringgold, Union46 min
Jun 19, 12:13 AM CDTSevere Thunderstorm WarningDMXAdams26 min
Jun 19, 12:14 AM CDTSevere Thunderstorm WarningDMXDavis, Wapello31 min
Jun 19, 12:25 AM CDTSevere Thunderstorm WarningDMXClarke, Lucas, Marion, Warren35 min
Jun 19, 12:29 AM CDTSevere Thunderstorm WarningDMXAppanoose, Davis46 min
Jun 19, 12:44 AM CDTSevere Thunderstorm WarningDMXLucas, Marion, Monroe31 min
Jun 19, 3:59 AM CDTSpecial Weather StatementDMXDavis46 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2021Every severe thunderstorm warning in 2021

Sources

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