Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 80, NWS Des Moines, IA

July 14, 2021Poweshiek County, Tama County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Jul 14, 2021, 8:45 PM CDT for Poweshiek County, Tama County, Iowa. It was in force for 45 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jul 14, 2021, 8:45 PM CDT (01:45 UTC)
Expired
Jul 14, 2021, 9:30 PM CDT
In force
45 min
Issued by
NWS Des Moines, IA
Area
Storm-based polygon
Tornado
Possible
Hail
0.75 in
Wind
60.0 mph

Counties Poweshiek County, IA, Tama County, IA

The radar

The Des Moines radar (KDMX), 95 km from the middle of the area, began a volume at 01:48 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.

IssuedProductOfficeLasted
Jul 14, 2:35 PM CDTTornado WatchSPC8 hr

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 1.8 hours before the alert went out and 174 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 2021-07-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2569 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Davenport, at 00:00Z on 2021-07-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 253 square meters per square second.193958Sfc1 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
2569 J/kg
Mixed-layer CIN
-10 J/kg
Mixed-layer LCL
832 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
253 m²/s²
0-3 km storm-relative helicity
346 m²/s²
Significant tornado parameter
3.2
Supercell composite
23.4

Open this sounding in Storm Lab

The text

As transmitted.

262 
WUUS53 KDMX 150145
SVRDMX
IAC157-171-150230-
/O.NEW.KDMX.SV.W.0080.210715T0145Z-210715T0230Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Des Moines IA
845 PM CDT Wed Jul 14 2021

The National Weather Service in Des Moines  has issued a

* Severe Thunderstorm Warning for...
  Northern Poweshiek County in central Iowa...
  Southern Tama County in central Iowa...

* Until 930 PM CDT.

* At 844 PM CDT, a severe thunderstorm was located 8 miles north of
  Grinnell, moving east at 30 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to roofs, siding, and trees.

* Locations impacted include...
  Grinnell, Toledo, Tama, Brooklyn, Meskwaki Casino, Le Grand,
  Victor, Holiday Lake, Malcom, Chelsea, Montour, Elberon, Hartwick,
  Vining, Grinnell Regional Airport and Toledo Municipal Airport.

This includes Interstate 80 between mile markers 193 and 204.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 900 PM CDT for central Iowa.

Intense thunderstorm lines can produce brief tornadoes and 
widespread significant wind damage. Although a tornado is not 
immediately likely, it is best to move to an interior room on the 
lowest floor of a building. This storm may cause serious injury and 
significant property damage.

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

&&

LAT...LON 4170 9277 4207 9277 4205 9230 4168 9230
TIME...MOT...LOC 0144Z 276DEG 28KT 4186 9271 

TORNADO...POSSIBLE
HAIL...<.75IN
WIND...60MPH
 
$$

Fowle
3 follow-up statements
976 
WWUS53 KDMX 150205
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
905 PM CDT Wed Jul 14 2021

IAC157-171-150230-
/O.CON.KDMX.SV.W.0080.000000T0000Z-210715T0230Z/
Poweshiek IA-Tama IA-
905 PM CDT Wed Jul 14 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 930 PM CDT
FOR NORTHERN POWESHIEK AND SOUTHERN TAMA COUNTIES...

At 905 PM CDT, a severe thunderstorm was located 7 miles west of
Belle Plaine, or 12 miles southeast of Toledo, moving east at 40 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

Locations impacted include...
Grinnell, Toledo, Tama, Brooklyn, Meskwaki Casino, Le Grand, Victor,
Holiday Lake, Malcom, Chelsea, Montour, Elberon, Hartwick, Vining,
Grinnell Regional Airport and Toledo Municipal Airport.

This includes Interstate 80 between mile markers 193 and 204.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 1100 PM CDT for central Iowa.

Intense thunderstorm lines can produce brief tornadoes and widespread
significant wind damage. Although a tornado is not immediately
likely, it is best to move to an interior room on the lowest floor of
a building. This storm may cause serious injury and significant
property damage.

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

&&

LAT...LON 4170 9277 4207 9277 4205 9230 4168 9230
TIME...MOT...LOC 0205Z 271DEG 35KT 4186 9242 

TORNADO...POSSIBLE
HAIL...<.75IN
WIND...60MPH
 
$$

Fowle
192 
WWUS53 KDMX 150210
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
910 PM CDT Wed Jul 14 2021

IAC157-171-150230-
/O.CON.KDMX.SV.W.0080.000000T0000Z-210715T0230Z/
Poweshiek IA-Tama IA-
910 PM CDT Wed Jul 14 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 930 PM CDT
FOR NORTHERN POWESHIEK AND SOUTHERN TAMA COUNTIES...

At 909 PM CDT, a severe thunderstorm was located near Belle Plaine,
or 14 miles southeast of Toledo, moving east at 30 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

Locations impacted include...
Grinnell, Tama, Brooklyn, Victor, Holiday Lake, Malcom, Chelsea,
Hartwick and Grinnell Regional Airport.

This includes Interstate 80 between mile markers 193 and 204.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 1100 PM CDT for central Iowa.

Intense thunderstorm lines can produce brief tornadoes and widespread
significant wind damage. Although a tornado is not immediately
likely, it is best to move to an interior room on the lowest floor of
a building. This storm may cause serious injury and significant
property damage.

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

&&

LAT...LON 4170 9277 4197 9277 4198 9230 4168 9230
TIME...MOT...LOC 0209Z 276DEG 28KT 4186 9237 

TORNADO...POSSIBLE
HAIL...<.75IN
WIND...60MPH
 
$$

Fowle
049 
WWUS53 KDMX 150226
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
926 PM CDT Wed Jul 14 2021

IAC157-171-150236-
/O.EXP.KDMX.SV.W.0080.000000T0000Z-210715T0230Z/
Poweshiek IA-Tama IA-
926 PM CDT Wed Jul 14 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHERN POWESHIEK AND
SOUTHERN TAMA COUNTIES WILL EXPIRE AT 930 PM CDT...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning will be allowed to expire.  However gusty
winds and heavy rain are still possible with this thunderstorm.

A Tornado Watch remains in effect until 1100 PM CDT for central Iowa.

LAT...LON 4170 9277 4197 9277 4198 9230 4168 9230
TIME...MOT...LOC 0226Z 281DEG 27KT 4177 9224 

$$

Fowle

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 14, 7:03 PM CDTSpecial Weather StatementDMXStory42 min
Jul 14, 7:23 PM CDTSevere Thunderstorm WarningDMXJasper, Marshall, Polk, Story67 min
Jul 14, 7:29 PM CDTSevere Thunderstorm WarningDMXTama14 min
Jul 14, 8:10 PM CDTTornado WarningDMXMarshall35 min
Jul 14, 8:28 PM CDTFlash Flood WarningDMXMarshall, Polk, Story6 hr
Jul 14, 8:42 PM CDTSevere Thunderstorm WarningDMXJasper, Marshall, Polk, Story43 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.