Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 46, NWS Omaha, NE

June 18, 2021Pottawattamie County, Iowa

NWS Omaha, NE issued this severe thunderstorm warning at Jun 18, 2021, 11:56 PM CDT for Pottawattamie County, Iowa. It was in force for 38 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: Jun 18, 2021, 11:56 PM CDT (04:56 UTC)
Expired: Jun 19, 2021, 12:34 AM CDT
In force: 38 min
Issued by: NWS Omaha, NE
Area: Storm-based polygon
Hail: 1.25 in
Wind: 60.0 mph

County Pottawattamie County, IA

The radar

The Omaha radar (KOAX), 81 km from the middle of the area, began a volume at 04:57 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 00:00Z, 4.9 hours before the alert went out and 81 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: 2090 J/kg
Mixed-layer CIN: -169 J/kg
Mixed-layer LCL: 1569 m above ground
0-6 km bulk shear: 59 kt
0-1 km storm-relative helicity: 46 m²/s²
0-3 km storm-relative helicity: 307 m²/s²
Significant tornado parameter: -0.0
Supercell composite: -0.3

Open this sounding in Storm Lab

The text

As transmitted.

475 
WUUS53 KOAX 190456
SVROAX
IAC155-190545-
/O.NEW.KOAX.SV.W.0046.210619T0456Z-210619T0545Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Omaha/Valley Nebraska
1156 PM CDT Fri Jun 18 2021

The National Weather Service in Omaha has issued a

* Severe Thunderstorm Warning for...
  Southeastern Pottawattamie County in southwestern Iowa...

* Until 1245 AM CDT.

* At 1155 PM CDT, a severe thunderstorm was located over Macedonia,
  or 27 miles southwest of Atlantic, moving east at 40 mph.

  HAZARD...60 mph wind gusts and half dollar 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...
  Oakland around 1205 AM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4116 9556 4128 9561 4135 9516 4116 9516
TIME...MOT...LOC 0455Z 250DEG 37KT 4118 9545 

HAIL...1.25IN
WIND...60MPH
 
$$

DeWald

4 follow-up statements

008 
WWUS53 KOAX 190501 RRA
SVSOAX

Severe Weather Statement
National Weather Service Omaha/Valley Nebraska
1201 AM CDT Sat Jun 19 2021

IAC155-190545-
/O.CON.KOAX.SV.W.0046.000000T0000Z-210619T0545Z/
Pottawattamie IA-
1201 AM CDT Sat Jun 19 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1245 AM CDT
FOR SOUTHEASTERN POTTAWATTAMIE COUNTY...

At 1201 AM CDT, a severe thunderstorm was located over Carson, or 25
miles southwest of Atlantic, moving east at 35 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.

This severe storm will be near...
  Carson around 1205 AM CDT.
  Oakland around 1210 AM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4116 9552 4129 9556 4135 9516 4116 9516
TIME...MOT...LOC 0501Z 253DEG 31KT 4123 9546 

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

DeWald

494 
WWUS53 KOAX 190510
SVSOAX

Severe Weather Statement
National Weather Service Omaha/Valley Nebraska
1210 AM CDT Sat Jun 19 2021

IAC155-190545-
/O.CON.KOAX.SV.W.0046.000000T0000Z-210619T0545Z/
Pottawattamie IA-
1210 AM CDT Sat Jun 19 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1245 AM CDT
FOR SOUTHEASTERN POTTAWATTAMIE COUNTY...

At 1210 AM CDT, a severe thunderstorm was located near Carson, or 20
miles southwest of Atlantic, 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
southeastern Pottawattamie County, including the following
locations... Farm Creek Public Wildlife Area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4116 9543 4130 9546 4135 9516 4116 9516
TIME...MOT...LOC 0510Z 251DEG 36KT 4124 9535 

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

DeWald

381 
WWUS53 KOAX 190530
SVSOAX

Severe Weather Statement
National Weather Service Omaha/Valley Nebraska
1230 AM CDT Sat Jun 19 2021

IAC155-190545-
/O.CON.KOAX.SV.W.0046.000000T0000Z-210619T0545Z/
Pottawattamie IA-
1230 AM CDT Sat Jun 19 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1245 AM CDT
FOR SOUTHEASTERN POTTAWATTAMIE COUNTY...

At 1230 AM CDT, a severe thunderstorm was located west of Griswold, 
or 11 miles southwest of Atlantic, 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
southeastern Pottawattamie County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4116 9530 4129 9530 4133 9516 4116 9516
TIME...MOT...LOC 0530Z 251DEG 34KT 4126 9516 

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

DeWald

042 
WWUS53 KOAX 190534
SVSOAX

Severe Weather Statement
National Weather Service Omaha/Valley Nebraska
1234 AM CDT Sat Jun 19 2021

IAC155-190543-
/O.CAN.KOAX.SV.W.0046.000000T0000Z-210619T0545Z/
Pottawattamie IA-
1234 AM CDT Sat Jun 19 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN POTTAWATTAMIE
COUNTY IS CANCELLED...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning has
been cancelled.

LAT...LON 4116 9530 4129 9530 4133 9516 4116 9516
TIME...MOT...LOC 0532Z 250DEG 37KT 4127 9511 

$$

DeWald

The office that day

Everything else NWS Omaha, NE issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 18, 11:07 PM CDT	Severe Thunderstorm Warning	OAX	Pottawattamie	38 min
Jun 18, 11:09 PM CDT	Special Weather Statement	OAX	Mills	21 min
Jun 18, 11:24 PM CDT	Special Weather Statement	OAX	Mills	21 min
Jun 18, 11:27 PM CDT	Severe Thunderstorm Warning	OAX	Mills	38 min
Jun 18, 11:43 PM CDT	Severe Thunderstorm Warning	OAX	Montgomery, Pottawattamie	47 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.