Alert archive / Iowa / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 45, NWS Des Moines, IA
NWS Des Moines, IA issued this severe thunderstorm warning at Jun 20, 2021, 7:59 PM CDT for Jasper County, Poweshiek County, Tama County, Iowa. It was in force for 20 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 20, 2021, 7:59 PM CDT (00:59 UTC)
- Expired
- Jun 20, 2021, 8:19 PM CDT
- In force
- 20 min
- Issued by
- NWS Des Moines, IA
- Area
- Storm-based polygon
- Tornado
- Possible
- Hail
- 0.88 in
- Wind
- 60.0 mph
Counties Jasper County, IA, Poweshiek County, IA, Tama County, IA
The radar
The Des Moines radar (KDMX), 87 km from the middle of the area, began a volume at 01:00 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.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Jun 20, 1:42 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 20, 4:01 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
The nearest sounding before it
Davenport, (KDVN), launched 00:00Z, 1.0 hours before the alert went out and 182 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.
- Mixed-layer CAPE
- 1058 J/kg
- Mixed-layer CIN
- -19 J/kg
- Mixed-layer LCL
- 1009 m above ground
- 0-6 km bulk shear
- 52 kt
- 0-1 km storm-relative helicity
- 174 m²/s²
- 0-3 km storm-relative helicity
- 230 m²/s²
- Significant tornado parameter
- 1.4
- Supercell composite
- 7.8
The text
As transmitted.
804
WUUS53 KDMX 210059
SVRDMX
IAC099-157-171-210200-
/O.NEW.KDMX.SV.W.0045.210621T0059Z-210621T0200Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Des Moines IA
759 PM CDT Sun Jun 20 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...
Northeastern Jasper County in central Iowa...
* Until 900 PM CDT.
* At 759 PM CDT, a severe thunderstorm was located over Grinnell,
moving east at 20 mph.
HAZARD...60 mph wind gusts and nickel size hail.
SOURCE...Radar indicated.
IMPACT...Expect damage to roofs, siding, and trees.
* Locations impacted include...
Brooklyn and Victor.
This includes Interstate 80 between mile markers 191 and 204.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 4175 9289 4186 9280 4186 9277 4187 9277
4191 9230 4164 9230
TIME...MOT...LOC 0059Z 283DEG 19KT 4177 9273
TORNADO...POSSIBLE
HAIL...0.88IN
WIND...60MPH
$$
REV2 follow-up statements
460
WWUS53 KDMX 210113
SVSDMX
Severe Weather Statement
National Weather Service Des Moines IA
813 PM CDT Sun Jun 20 2021
IAC171-210123-
/O.CAN.KDMX.SV.W.0045.000000T0000Z-210621T0200Z/
Tama IA-
813 PM CDT Sun Jun 20 2021
...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN TAMA COUNTY IS
CANCELLED...
The severe thunderstorm which prompted the warning has moved out of
the warned area. Therefore, the warning has been cancelled.
A Severe Thunderstorm Watch remains in effect until 1100 PM CDT for
central Iowa.
LAT...LON 4173 9277 4181 9270 4183 9268 4186 9263
4185 9230 4164 9230
TIME...MOT...LOC 0113Z 283DEG 19KT 4175 9263
$$
IAC099-157-210200-
/O.CON.KDMX.SV.W.0045.000000T0000Z-210621T0200Z/
Poweshiek IA-Jasper IA-
813 PM CDT Sun Jun 20 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 900 PM CDT
FOR NORTHERN POWESHIEK AND EASTERN JASPER COUNTIES...
At 813 PM CDT, a severe thunderstorm was located near Grinnell,
moving east at 20 mph.
HAZARD...60 mph wind gusts and nickel size hail.
SOURCE...Radar indicated.
IMPACT...Expect damage to roofs, siding, and trees.
Locations impacted include...
Grinnell, Brooklyn, Victor, Holiday Lake, Malcom, Hartwick and
Guernsey.
This includes Interstate 80 between mile markers 191 and 204.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 4173 9277 4181 9270 4183 9268 4186 9263
4185 9230 4164 9230
TIME...MOT...LOC 0113Z 283DEG 19KT 4175 9263
HAIL...0.88IN
WIND...60MPH
$$
REV325
WWUS53 KDMX 210119
SVSDMX
Severe Weather Statement
National Weather Service Des Moines IA
819 PM CDT Sun Jun 20 2021
IAC099-157-210128-
/O.CAN.KDMX.SV.W.0045.000000T0000Z-210621T0200Z/
Poweshiek IA-Jasper IA-
819 PM CDT Sun Jun 20 2021
...THE SEVERE THUNDERSTORM WARNING FOR NORTHERN POWESHIEK AND EASTERN
JASPER COUNTIES IS CANCELLED...
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning has been cancelled. However gusty winds are
still possible with this thunderstorm.
A Severe Thunderstorm Watch remains in effect until 1100 PM CDT for
central Iowa.
To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Des Moines .
LAT...LON 4173 9277 4181 9270 4183 9268 4186 9263
4185 9230 4164 9230
TIME...MOT...LOC 0117Z 283DEG 19KT 4174 9259
$$
REVThe office that day
Everything else NWS Des Moines, IA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 20, 7:17 PM CDT | Severe Thunderstorm Warning | DMX | Black Hawk, Tama | 43 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.