Alert archive / Iowa / Tornado Warnings in 2021

Tornado Warning 23, NWS Quad Cities, IA

August 11, 2021Dubuque County, Iowa

NWS Quad Cities, IA issued this tornado warning at Aug 11, 2021, 5:38 PM CDT for Dubuque County, Iowa. It was in force for 13 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: Aug 11, 2021, 5:38 PM CDT (22:38 UTC)
Expired: Aug 11, 2021, 5:51 PM CDT
In force: 13 min
Issued by: NWS Quad Cities, IA
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.75 in

County Dubuque County, IA

The radar

The Quad Cities radar (KDVN), 92 km from the middle of the area, began a volume at 22:40 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
Aug 11, 5:40 PM CDT	TORNADO	2 Se Farley, IA	EMERGENCY MANAGER REPORTED A TORNADO TOUCHDOWN IN A FIELD WITH A NOTICEABLE DAMAGE PATH, DAMAGING CROPS AND ENDING IN NEARBY TIMBER. SIGNIFICANT BRANCH DAMAGE IN TIMBER.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 10.6 hours before the alert went out and 94 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: 2852 J/kg
Mixed-layer CIN: -107 J/kg
Mixed-layer LCL: 1040 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 170 m²/s²
0-3 km storm-relative helicity: 193 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 3.7

Open this sounding in Storm Lab

The text

As transmitted.

675 
WFUS53 KDVN 112238
TORDVN
IAC061-112315-
/O.NEW.KDVN.TO.W.0023.210811T2238Z-210811T2315Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Quad Cities IA/IL
538 PM CDT Wed Aug 11 2021

The National Weather Service in the Quad Cities has issued a

* Tornado Warning for...
  Southwestern Dubuque County in northeastern Iowa...

* Until 615 PM CDT.
    
* At 538 PM CDT, a severe thunderstorm capable of producing a tornado
  was located near Farley, or 17 miles southwest of Dubuque, moving
  east at 15 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...
  Epworth around 555 PM CDT.

Other locations in the path of this tornadic thunderstorm include
Peosta.

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 4236 9107 4244 9107 4245 9085 4232 9084
TIME...MOT...LOC 2238Z 267DEG 12KT 4239 9100 

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

$$

Ervin

2 follow-up statements

933 
WWUS53 KDVN 112243
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
543 PM CDT Wed Aug 11 2021

IAC061-112315-
/O.CON.KDVN.TO.W.0023.000000T0000Z-210811T2315Z/
Dubuque IA-
543 PM CDT Wed Aug 11 2021

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 615 PM CDT FOR
SOUTHWESTERN DUBUQUE COUNTY...
    
At 543 PM CDT, a severe thunderstorm capable of producing a tornado
was located near Epworth, or 15 miles southwest of Dubuque, moving
east at 15 mph.

HAZARD...Tornado and ping pong ball size hail.

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...
  Epworth around 555 PM CDT.

Other locations in the path of this tornadic thunderstorm include
Peosta.

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 4236 9104 4244 9103 4245 9085 4232 9084
TIME...MOT...LOC 2243Z 264DEG 12KT 4240 9097 

TORNADO...RADAR INDICATED
MAX HAIL SIZE...1.50 IN

$$

Ervin

063 
WWUS53 KDVN 112251
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
551 PM CDT Wed Aug 11 2021

IAC061-112301-
/O.CAN.KDVN.TO.W.0023.000000T0000Z-210811T2315Z/
Dubuque IA-
551 PM CDT Wed Aug 11 2021

...THE TORNADO WARNING FOR SOUTHWESTERN DUBUQUE COUNTY IS
CANCELLED...
                
The storm which prompted the warning has weakened below severe
limits, and no longer appears capable of producing a tornado.
Therefore, the warning has been cancelled.

LAT...LON 4236 9104 4244 9103 4245 9085 4232 9084
TIME...MOT...LOC 2250Z 267DEG 12KT 4240 9093 

$$

Ervin

The office that day

Everything else NWS Quad Cities, IA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 11, 5:38 AM CDT	Special Weather Statement	DVN	Lee	37 min
Aug 11, 5:56 AM CDT	Severe Thunderstorm Warning	DVN	Des Moines, Lee	19 min
Aug 11, 6:10 AM CDT	Severe Thunderstorm Warning	DVN	Des Moines, Henry, Lee	20 min
Aug 11, 6:24 AM CDT	Severe Thunderstorm Warning	DVN	Des Moines	22 min
Aug 11, 6:38 AM CDT	Severe Thunderstorm Warning	DVN	Des Moines, Louisa	37 min
Aug 11, 6:59 AM CDT	Flash Flood Warning	DVN	Des Moines, Lee	3 hr
Aug 11, 7:04 AM CDT	Special Weather Statement	DVN	Muscatine	26 min
Aug 11, 8:16 AM CDT	High Wind Warning	DVN	Clinton, Des Moines, Louisa, Muscatine, Scott	104 min
Aug 11, 9:46 AM CDT	Areal Flood Warning	DVN	Des Moines, Lee	3 hr
Aug 11, 10:24 AM CDT	Special Weather Statement	DVN	Lee	21 min
Aug 11, 3:36 PM CDT	Special Weather Statement	DVN	Washington	24 min
Aug 11, 4:26 PM CDT	Severe Thunderstorm Warning	DVN	Delaware, Dubuque	49 min
Aug 11, 5:11 PM CDT	Severe Thunderstorm Warning	DVN	Delaware, Dubuque, Jackson, Jones	49 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.