Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 57, NWS Des Moines, IA

July 9, 2021Adair County, Adams County, Union County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Jul 9, 2021, 8:09 AM CDT for Adair County, Adams County, Union County, Iowa. It was in force for 28 min. 2 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: Jul 9, 2021, 8:09 AM CDT (13:09 UTC)
Expired: Jul 9, 2021, 8:37 AM CDT
In force: 28 min
Issued by: NWS Des Moines, IA
Area: Storm-based polygon
Hail: 1.5 in
Wind: 60.0 mph

Counties Adair County, IA, Adams County, IA, Union County, IA

The radar

The Des Moines radar (KDMX), 96 km from the middle of the area, began a volume at 13:10 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

Time	Report	Where	Remark
Jul 9, 8:15 AM CDT	HAIL 1.75	5 Sse Fontanelle, IA	LARGEST STONES WERE GOLFBALL SIZED, MOSTLY QUARTER SIZED STONES. GROUND WHITE. NO WIND.
Jul 9, 8:33 AM CDT	HAIL 1	2 Nnw Greenfield, IA	DELAYED REPORT.

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

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 1.2 hours before the alert went out and 162 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: 428 J/kg
Mixed-layer CIN: -350 J/kg
Mixed-layer LCL: 881 m above ground
0-6 km bulk shear: 63 kt
0-1 km storm-relative helicity: 404 m²/s²
0-3 km storm-relative helicity: 551 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.9

Open this sounding in Storm Lab

The text

As transmitted.

715 
WUUS53 KDMX 091309
SVRDMX
IAC001-003-175-091400-
/O.NEW.KDMX.SV.W.0057.210709T1309Z-210709T1400Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Des Moines IA
809 AM CDT Fri Jul 9 2021

The National Weather Service in Des Moines  has issued a

* Severe Thunderstorm Warning for...
  Union County in south central Iowa...
  Eastern Adams County in southwestern Iowa...
  Southwestern Adair County in southwestern Iowa...

* Until 900 AM CDT.

* At 809 AM CDT, a severe thunderstorm was located 7 miles southwest
  of Greenfield, moving southeast at 25 mph.

  HAZARD...Ping pong ball size hail and 60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...People and animals outdoors will be injured. Expect hail 
           damage to roofs, siding, windows, and vehicles. Expect 
           wind damage to roofs, siding, and trees.

* Locations impacted include...
  Green Valley Lake and Creston.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4090 9455 4129 9469 4135 9444 4090 9408
TIME...MOT...LOC 1309Z 323DEG 24KT 4123 9456 

HAIL...1.50IN
WIND...60MPH
 
$$

Podrazik

2 follow-up statements

886 
WWUS53 KDMX 091327
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
827 AM CDT Fri Jul 9 2021

IAC001-003-175-091400-
/O.CON.KDMX.SV.W.0057.000000T0000Z-210709T1400Z/
Union IA-Adams IA-Adair IA-
827 AM CDT Fri Jul 9 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 900 AM CDT
FOR UNION...EASTERN ADAMS AND SOUTH CENTRAL ADAIR COUNTIES...

At 826 AM CDT, a severe thunderstorm was located near Green Valley
Lake, or 8 miles northwest of Creston, moving southeast at 25 mph.

HAZARD...Ping pong ball size hail and 60 mph wind gusts.

SOURCE...Trained weather spotters. At 815 AM, a trained weather 
         spotter located 5 miles southeast of Fontanelle reported 
         hail to the size of golf balls that covered the ground.

IMPACT...People and animals outdoors will be injured. Expect hail 
         damage to roofs, siding, windows, and vehicles. Expect wind 
         damage to roofs, siding, and trees.

Locations impacted include...
Creston, Lenox, Green Valley Lake, Afton, Orient, Cromwell, Arispe,
Shannon City, Kent, Green Valley Lake State Park and Creston
Municipal Airport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4090 9455 4119 9463 4125 9436 4090 9408
TIME...MOT...LOC 1326Z 326DEG 22KT 4115 9446 

HAIL...1.50IN
WIND...60MPH
 
$$

Podrazik

815 
WWUS53 KDMX 091337
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
837 AM CDT Fri Jul 9 2021

IAC001-003-175-091347-
/O.CAN.KDMX.SV.W.0057.000000T0000Z-210709T1400Z/
Union IA-Adams IA-Adair IA-
837 AM CDT Fri Jul 9 2021

...THE SEVERE THUNDERSTORM WARNING FOR UNION...EASTERN ADAMS AND
SOUTH CENTRAL ADAIR COUNTIES IS CANCELLED...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning has been cancelled.  However gusty winds are
still possible with this thunderstorm.

LAT...LON 4090 9455 4119 9463 4125 9436 4090 9408
TIME...MOT...LOC 1332Z 323DEG 24KT 4109 9440 

$$

Podrazik

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 9, 2:59 AM CDT	Flood Watch	DMX	Appanoose, Davis, Monroe, Wapello, Wayne	13 min
Jul 9, 3:12 AM CDT	Flash Flood Watch	DMX	Appanoose, Clarke, Davis, Decatur, Lucas, Madison and 4 more	30 hr
Jul 9, 9:24 AM CDT	Special Weather Statement	DMX	Wayne	21 min
Jul 9, 12:04 PM CDT	Special Weather Statement	DMX	Webster	26 min
Jul 9, 12:28 PM CDT	Severe Thunderstorm Warning	DMX	Boone, Greene, Hamilton, Webster	47 min
Jul 9, 1:01 PM CDT	Severe Thunderstorm Warning	DMX	Boone, Dallas, Greene, Polk, Story	44 min
Jul 9, 1:27 PM CDT	Severe Thunderstorm Warning	DMX	Boone, Dallas, Madison, Polk, Story	63 min
Jul 9, 2:06 PM CDT	Severe Thunderstorm Warning	DMX	Jasper, Madison, Marion, Polk, Warren	54 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2021 Every 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.