Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 45, NWS Omaha, NE

June 18, 2021Montgomery County, Pottawattamie County, Iowa

NWS Omaha, NE issued this severe thunderstorm warning at Jun 18, 2021, 11:43 PM CDT for Montgomery County, Pottawattamie County, Iowa. It was in force for 47 min. 1 report 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, 11:43 PM CDT (04:43 UTC)
Expired: Jun 19, 2021, 12:30 AM CDT
In force: 47 min
Issued by: NWS Omaha, NE
Area: Storm-based polygon
Hail: 1.75 in
Wind: 60.0 mph

Counties Montgomery County, IA, Pottawattamie County, IA

The radar

The Omaha radar (KOAX), 102 km from the middle of the area, began a volume at 04:46 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
Jun 19, 12:00 AM CDT	HAIL 2	4 W Grant, IA	EMERGENCY MANAGER REPORTS HAIL RANGING FROM THE SIZED OF PING PONGS TO GOLF BALLS. A FEW LARGER THAN GOLF BALL SIZED STONES WERE ALSO NOTED.

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.

Issued	Product	Office	Lasted
Jun 18, 10:08 PM CDT	Severe Thunderstorm Watch	SPC	8 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 4.7 hours before the alert went out and 102 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.

699 
WUUS53 KOAX 190443
SVROAX
IAC137-155-190530-
/O.NEW.KOAX.SV.W.0045.210619T0443Z-210619T0530Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Omaha/Valley Nebraska
1143 PM CDT Fri Jun 18 2021

The National Weather Service in Omaha has issued a

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

* Until 1230 AM CDT.

* At 1142 PM CDT, a severe thunderstorm was located west of 
  Griswold, or 16 miles southwest of Atlantic, moving east at 30 mph.

  HAZARD...Golf 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 thunderstorm will remain over mainly rural areas of
  northern Montgomery and southeastern Pottawattamie Counties,
  including the following locations... Grant and Farm Creek Public
  Wildlife Area.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4111 9536 4131 9529 4130 9515 4116 9515
      4116 9492 4102 9493
TIME...MOT...LOC 0442Z 279DEG 26KT 4122 9522 

HAIL...1.75IN
WIND...60MPH
 
$$

DeWald

4 follow-up statements

293 
WWUS53 KOAX 190459
SVSOAX

Severe Weather Statement
National Weather Service Omaha/Valley Nebraska
1159 PM CDT Fri Jun 18 2021

IAC155-190507-
/O.CAN.KOAX.SV.W.0045.000000T0000Z-210619T0530Z/
Pottawattamie IA-
1159 PM CDT Fri Jun 18 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN POTTAWATTAMIE
COUNTY IS CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, this warning has been cancelled. 
However, a new severe thunderstorm is expected to move in from the 
west through 1230 am. 

A Severe Thunderstorm Watch remains in effect until 500 AM CDT for
southwestern Iowa.

LAT...LON 4108 9521 4116 9517 4116 9493 4111 9492
      4102 9493
TIME...MOT...LOC 0457Z 287DEG 25KT 4115 9511 

$$

IAC137-190530-
/O.CON.KOAX.SV.W.0045.000000T0000Z-210619T0530Z/
Montgomery IA-
1159 PM CDT Fri Jun 18 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1230 AM CDT
FOR NORTHEASTERN MONTGOMERY COUNTY...

At 1157 PM CDT, a severe thunderstorm was located near Elliott, or 17
miles south of Atlantic, moving east at 30 mph.

HAZARD...Golf 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...
 Elliott and Grant. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4108 9521 4116 9517 4116 9493 4111 9492
      4102 9493
TIME...MOT...LOC 0457Z 287DEG 25KT 4115 9511 

HAIL...1.75IN
WIND...60MPH
 
$$

DeWald

001 
WWUS53 KOAX 190509
SVSOAX

Severe Weather Statement
National Weather Service Omaha/Valley Nebraska
1209 AM CDT Sat Jun 19 2021

IAC137-190530-
/O.CON.KOAX.SV.W.0045.000000T0000Z-210619T0530Z/
Montgomery IA-
1209 AM CDT Sat Jun 19 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1230 AM CDT
FOR NORTHEASTERN MONTGOMERY COUNTY...

At 1208 AM CDT, a severe thunderstorm was located 8 miles east of
Elliott, or 16 miles northwest of Corning, moving east at 30 mph.

HAZARD...Golf ball size hail and 60 mph wind gusts.

SOURCE...Emergency management.

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...
Elliott and Grant. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4108 9521 4116 9517 4116 9493 4111 9492
      4102 9493
TIME...MOT...LOC 0508Z 279DEG 26KT 4114 9500 

HAIL...1.75IN
WIND...60MPH
 
$$

DeWald

030 
WWUS53 KOAX 190519
SVSOAX

Severe Weather Statement
National Weather Service Omaha/Valley Nebraska
1219 AM CDT Sat Jun 19 2021

IAC137-190530-
/O.CON.KOAX.SV.W.0045.000000T0000Z-210619T0530Z/
Montgomery IA-
1219 AM CDT Sat Jun 19 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1230 AM CDT
FOR NORTHEASTERN MONTGOMERY COUNTY...

At 1219 AM CDT, a severe thunderstorm was located 10 miles west of
Lake Icaria, or 12 miles northwest of Corning, moving east at 30 mph.

HAZARD...Golf ball size hail and 60 mph wind gusts.

SOURCE...Emergency management.

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...
Grant.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4107 9506 4116 9505 4116 9493 4111 9492
      4104 9493
TIME...MOT...LOC 0519Z 280DEG 25KT 4111 9491 

HAIL...1.75IN
WIND...60MPH
 
$$

DeWald

603 
WWUS53 KOAX 190522
SVSOAX

Severe Weather Statement
National Weather Service Omaha/Valley Nebraska
1222 AM CDT Sat Jun 19 2021

IAC137-190532-
/O.EXP.KOAX.SV.W.0045.000000T0000Z-210619T0530Z/
Montgomery IA-
1222 AM CDT Sat Jun 19 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN MONTGOMERY COUNTY
WILL EXPIRE AT 1230 AM CDT...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning will be allowed to expire.

A Severe Thunderstorm Watch remains in effect until 500 AM CDT for
southwestern Iowa.

LAT...LON 4107 9506 4116 9505 4116 9493 4111 9492
      4104 9493
TIME...MOT...LOC 0522Z 279DEG 26KT 4111 9491 

$$

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, 11:56 PM CDT	Severe Thunderstorm Warning	OAX	Pottawattamie	38 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.