Alert archive / Iowa / Tornado Warnings in 2021
Tornado Warning 1, NWS Des Moines, IA
NWS Des Moines, IA issued this tornado warning at May 20, 2021, 9:39 PM CDT for Boone County, Dallas County, Iowa. It was in force for 22 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
- May 20, 2021, 9:39 PM CDT (02:39 UTC)
- Expired
- May 20, 2021, 10:01 PM CDT
- In force
- 22 min
- Issued by
- NWS Des Moines, IA
- Area
- Storm-based polygon
- Tornado
- Radar indicated
- Hail
- 0.0 in
Counties Boone County, IA, Dallas County, IA
The radar
The Des Moines radar (KDMX), 18 km from the middle of the area, began a volume at 02:37 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 |
|---|---|---|---|
| May 20, 9:45 PM CDT | TORNADO | 3 S Woodward, IA | BRIEF, WEAK TORNADO OCCURRED OVER RURAL NORTHEAST DALLAS COUNTY SOUTH AND SOUTHEAST OF WOODWARD. 1.5 MILE PATH. 50 YARDS WIDE. PEAK WIND 75 MPH. APPROXIMATE DURATION 945-950PM CDT. |
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 00:00Z, 2.7 hours before the alert went out and 213 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
- 214 J/kg
- Mixed-layer CIN
- 0 J/kg
- Mixed-layer LCL
- 588 m above ground
- 0-6 km bulk shear
- 41 kt
- 0-1 km storm-relative helicity
- 71 m²/s²
- 0-3 km storm-relative helicity
- 39 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 2.8
The text
As transmitted.
047
WFUS53 KDMX 210239
TORDMX
IAC015-049-210315-
/O.NEW.KDMX.TO.W.0001.210521T0239Z-210521T0315Z/
BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Des Moines IA
939 PM CDT Thu May 20 2021
The National Weather Service in Des Moines has issued a
* Tornado Warning for...
Southeastern Boone County in central Iowa...
Northeastern Dallas County in central Iowa...
* Until 1015 PM CDT.
* At 938 PM CDT, a shower capable of producing a tornado was located
near Granger, or 8 miles northwest of Grimes, moving north at 35
mph.
HAZARD...Tornado.
SOURCE...Radar indicated rotation.
IMPACT...Flying debris will be dangerous to those caught without
shelter. Mobile homes will be damaged or destroyed.
Damage to roofs, windows, and vehicles will occur. Tree
damage is likely.
* This dangerous storm will be near...
Woodward around 950 PM CDT.
Madrid around 955 PM CDT.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.
&&
LAT...LON 4173 9390 4174 9396 4198 9393 4195 9379
TIME...MOT...LOC 0238Z 193DEG 32KT 4176 9392
TORNADO...RADAR INDICATED
HAIL...0.00IN
$$
Ansorge2 follow-up statements
506
WWUS53 KDMX 210256
SVSDMX
Severe Weather Statement
National Weather Service Des Moines IA
956 PM CDT Thu May 20 2021
IAC049-210305-
/O.CAN.KDMX.TO.W.0001.000000T0000Z-210521T0315Z/
Dallas IA-
956 PM CDT Thu May 20 2021
...THE TORNADO WARNING FOR NORTHEASTERN DALLAS COUNTY IS CANCELLED...
The tornadic thunderstorm which prompted the warning has moved out
of the warned area. Therefore, the warning has been cancelled.
LAT...LON 4192 9394 4198 9393 4196 9383 4186 9388
4186 9394
TIME...MOT...LOC 0255Z 193DEG 32KT 4191 9387
$$
IAC015-210315-
/O.CON.KDMX.TO.W.0001.000000T0000Z-210521T0315Z/
Boone IA-
956 PM CDT Thu May 20 2021
...A TORNADO WARNING REMAINS IN EFFECT UNTIL 1015 PM CDT FOR SOUTH
CENTRAL BOONE COUNTY...
At 955 PM CDT, a shower capable of producing a tornado was located
north of Woodward, or 9 miles south of Boone, moving north at 35 mph.
HAZARD...Tornado.
SOURCE...Radar indicated rotation.
IMPACT...Flying debris will be dangerous to those caught without
shelter. Mobile homes will be damaged or destroyed. Damage
to roofs, windows, and vehicles will occur. Tree damage is
likely.
This tornadic thunderstorm will remain over mainly rural areas of
south central Boone County, including the following locations...
Ledges State Park.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.
&&
LAT...LON 4192 9394 4198 9393 4196 9383 4186 9388
4186 9394
TIME...MOT...LOC 0255Z 193DEG 32KT 4191 9387
TORNADO...RADAR INDICATED
HAIL...0.00IN
$$
Ansorge710
WWUS53 KDMX 210301
SVSDMX
Severe Weather Statement
National Weather Service Des Moines IA
1001 PM CDT Thu May 20 2021
IAC015-210311-
/O.CAN.KDMX.TO.W.0001.000000T0000Z-210521T0315Z/
Boone IA-
1001 PM CDT Thu May 20 2021
...THE TORNADO WARNING FOR SOUTH CENTRAL BOONE COUNTY IS CANCELLED...
The shower which prompted the warning has weakened below severe
limits, and no longer appears capable of producing a tornado.
Therefore, the warning has been cancelled.
To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Des Moines .
LAT...LON 4192 9394 4198 9393 4196 9383 4186 9388
4186 9394
TIME...MOT...LOC 0259Z 193DEG 32KT 4197 9385
$$
AnsorgeNearby
Tornado Warnings in Iowa, 2021Every tornado warning in 2021Tornadoes 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.