Alert archive / Iowa / Tornado Warnings in 2021

Tornado Warning 33, NWS Des Moines, IA

August 27, 2021Cerro Gordo County, Iowa

NWS Des Moines, IA issued this tornado warning at Aug 27, 2021, 5:23 PM CDT for Cerro Gordo County, Iowa. It was in force for 37 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: Aug 27, 2021, 5:23 PM CDT (22:23 UTC)
Expired: Aug 27, 2021, 6:00 PM CDT
In force: 37 min
Issued by: NWS Des Moines, IA
Area: Storm-based polygon
Tornado: Observed
Hail: 0.75 in

County Cerro Gordo County, IA

The radar

The Des Moines radar (KDMX), 163 km from the middle of the area, began a volume at 22:25 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
Aug 27, 5:15 PM CDT	Tornado Watch	SPC	6 hr

The nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 10.4 hours before the alert went out and 195 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: 487 J/kg
Mixed-layer CIN: -63 J/kg
Mixed-layer LCL: 644 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: -9 m²/s²
0-3 km storm-relative helicity: -16 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

559 
WFUS53 KDMX 272223
TORDMX
IAC033-272300-
/O.NEW.KDMX.TO.W.0033.210827T2223Z-210827T2300Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Des Moines IA
523 PM CDT Fri Aug 27 2021

The National Weather Service in Des Moines  has issued a

* Tornado Warning for...
  Northeastern Cerro Gordo County in north central Iowa...

* Until 600 PM CDT.
    
* At 523 PM CDT, a tornado producing storm was located near Mason
  City, moving northeast at 20 mph.

  HAZARD...Damaging tornado.

  SOURCE...Radar confirmed tornado.

  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 storm will be near...
  Nora Springs around 540 PM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

To repeat, a tornado is on the ground. 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 4322 9303 4305 9302 4302 9325 4315 9329
TIME...MOT...LOC 2223Z 246DEG 19KT 4310 9313 

TORNADO...OBSERVED
MAX HAIL SIZE...<.75 IN

$$

REV

2 follow-up statements

803 
WWUS53 KDMX 272244
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
544 PM CDT Fri Aug 27 2021

IAC033-272300-
/O.CON.KDMX.TO.W.0033.000000T0000Z-210827T2300Z/
Cerro Gordo IA-
544 PM CDT Fri Aug 27 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 600 PM CDT FOR EAST
CENTRAL CERRO GORDO COUNTY...
    
At 544 PM CDT, a severe thunderstorm capable of producing a tornado
was located over Nora Springs, or 9 miles east of Mason City, moving
northeast at 20 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
east central Cerro Gordo County.

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 4322 9303 4305 9302 4304 9313 4320 9309
TIME...MOT...LOC 2244Z 245DEG 18KT 4314 9301 

TORNADO...RADAR INDICATED
MAX HAIL SIZE...<.75 IN

$$

REV

769 
WWUS53 KDMX 272252
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
552 PM CDT Fri Aug 27 2021

IAC033-272300-
/O.EXP.KDMX.TO.W.0033.000000T0000Z-210827T2300Z/
Cerro Gordo IA-
552 PM CDT Fri Aug 27 2021

...THE TORNADO WARNING FOR EAST CENTRAL CERRO GORDO COUNTY WILL
EXPIRE AT 600 PM CDT...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning will be allowed to expire.

A Tornado Warning remains in effect for southeast Cerro Gordo County 
until 600 PM CDT.

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

LAT...LON 4322 9303 4305 9302 4304 9313 4320 9309
TIME...MOT...LOC 2250Z 246DEG 19KT 4315 9297 

$$

REV

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 26, 7:02 PM CDT	Severe Thunderstorm Warning	DMX	Audubon, Carroll	28 min
Aug 26, 8:35 PM CDT	Special Weather Statement	DMX	Poweshiek	40 min
Aug 26, 8:47 PM CDT	Severe Thunderstorm Warning	DMX	Mahaska, Poweshiek	58 min
Aug 26, 9:46 PM CDT	Special Weather Statement	DMX	Mahaska	44 min
Aug 26, 10:26 PM CDT	Special Weather Statement	DMX	Mahaska	34 min
Aug 26, 10:30 PM CDT	Severe Thunderstorm Warning	DMX	Emmet, Palo Alto	45 min
Aug 26, 10:52 PM CDT	Special Weather Statement	DMX	Wapello	38 min
Aug 26, 11:42 PM CDT	Severe Thunderstorm Warning	DMX	Emmet, Palo Alto	33 min
Aug 27, 12:13 AM CDT	Special Weather Statement	DMX	Emmet	32 min
Aug 27, 2:08 PM CDT	Special Weather Statement	DMX	Hancock	37 min
Aug 27, 2:59 PM CDT	Special Weather Statement	DMX	Cerro Gordo	16 min
Aug 27, 4:23 PM CDT	Severe Thunderstorm Warning	DMX	Cerro Gordo, Hancock	52 min
Aug 27, 4:48 PM CDT	Tornado Warning	DMX	Cerro Gordo, Hancock	57 min
Aug 27, 4:58 PM CDT	Severe Thunderstorm Warning	DMX	Cerro Gordo, Franklin, Hancock	32 min
Aug 27, 5:25 PM CDT	Tornado Warning	DMX	Cerro Gordo	35 min

Nearby

Tornado Warnings in Iowa, 2021 Every tornado warning in 2021 Tornadoes 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.