Alert archive / Iowa / Tornado Warnings in 2017

Tornado Warning 16, NWS La Crosse, WI

July 11, 2017Clayton County, Iowa

NWS La Crosse, WI issued this tornado warning at Jul 11, 2017, 10:12 PM CDT for Clayton County, Iowa. It was in force for 18 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: Jul 11, 2017, 10:12 PM CDT (03:12 UTC)
Expired: Jul 11, 2017, 10:30 PM CDT
In force: 18 min
Issued by: NWS La Crosse, WI
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 1.0 in

County Clayton County, IA

The radar

The La Crosse radar (KARX), 127 km from the middle of the area, began a volume at 03:14 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 nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 3.2 hours before the alert went out and 130 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: 1096 J/kg
Mixed-layer CIN: -33 J/kg
Mixed-layer LCL: 755 m above ground
0-6 km bulk shear: 44 kt
0-1 km storm-relative helicity: 268 m²/s²
0-3 km storm-relative helicity: 315 m²/s²
Significant tornado parameter: 1.5
Supercell composite: 7.6

Open this sounding in Storm Lab

The text

As transmitted.

634 
WFUS53 KARX 120312
TORARX
IAC043-120330-
/O.NEW.KARX.TO.W.0016.170712T0312Z-170712T0330Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service La Crosse WI
1012 PM CDT TUE JUL 11 2017

The National Weather Service in La Crosse has issued a

* Tornado Warning for...
  Southeastern Clayton County in northeastern Iowa...

* Until 1030 PM CDT
    
* At 1012 PM CDT, a severe thunderstorm capable of producing a
  tornado was located over Colesburg, or 9 miles south of Guttenberg,
  moving southeast at 20 mph.

  HAZARD...Tornado and quarter 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 tornadic thunderstorm will remain over mainly rural areas of
  southeastern Clayton 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 4272 9117 4265 9103 4265 9124
TIME...MOT...LOC 0312Z 316DEG 19KT 4265 9116 

TORNADO...RADAR INDICATED
HAIL...1.00IN

$$

CA

2 follow-up statements

772 
WWUS53 KARX 120321
SVSARX

Severe Weather Statement
National Weather Service La Crosse WI
1021 PM CDT TUE JUL 11 2017

IAC043-120330-
/O.CON.KARX.TO.W.0016.000000T0000Z-170712T0330Z/
Clayton IA-
1021 PM CDT TUE JUL 11 2017

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 1030 PM CDT FOR
SOUTHEASTERN CLAYTON COUNTY...
    
At 1021 PM CDT, a severe thunderstorm capable of producing a tornado
was located near Luxemburg, or 9 miles south of Guttenberg, moving
southeast at 20 mph.

HAZARD...Tornado and quarter 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 tornadic thunderstorm will remain over mainly rural areas of
southeastern Clayton 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 4272 9117 4265 9103 4265 9124
TIME...MOT...LOC 0321Z 307DEG 18KT 4265 9109 

TORNADO...RADAR INDICATED
HAIL...1.00IN

$$

CA

350 
WWUS53 KARX 120329
SVSARX

Severe Weather Statement
National Weather Service La Crosse WI
1029 PM CDT TUE JUL 11 2017

IAC043-120337-
/O.EXP.KARX.TO.W.0016.000000T0000Z-170712T0330Z/
Clayton IA-
1029 PM CDT TUE JUL 11 2017

...THE TORNADO WARNING FOR SOUTHEASTERN CLAYTON COUNTY WILL EXPIRE AT
1030 PM CDT...
        
The area of rotation which prompted the tornado warning has moved 
out of the area. Therefore the tornado warning will be allowed to 
expire. However, a Severe Thunderstorm Warning still remains in 
effect for southeastern Clayton and southwestern Grant counties. 

LAT...LON 4272 9117 4265 9103 4265 9124
TIME...MOT...LOC 0327Z 316DEG 19KT 4263 9107 

$$

CA

The office that day

Everything else NWS La Crosse, WI issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 11, 7:46 PM CDT	Special Weather Statement	ARX	Clayton	44 min
Jul 11, 8:35 PM CDT	Special Weather Statement	ARX	Clayton	70 min
Jul 11, 9:14 PM CDT	Special Weather Statement	ARX	Allamakee	46 min
Jul 11, 9:19 PM CDT	Tornado Warning	ARX	Clayton	26 min
Jul 11, 9:26 PM CDT	Areal Flood Advisory	ARX	Clayton, Fayette	3 hr
Jul 11, 9:44 PM CDT	Severe Thunderstorm Warning	ARX	Clayton	61 min
Jul 11, 10:14 PM CDT	Flash Flood Warning Emergency	ARX	Clayton	6 hr
Jul 12, 1:40 AM CDT	River Flood Warning	ARX	Clayton	24 hr
Jul 12, 1:40 AM CDT	River Flood Warning	ARX	Clayton	24 hr
Jul 12, 4:22 AM CDT	Areal Flood Warning Emergency	ARX	Clayton	6 hr
Jul 12, 8:44 AM CDT	Special Weather Statement	ARX	Chickasaw, Clayton, Fayette	31 min
Jul 12, 9:13 AM CDT	Special Weather Statement	ARX	Clayton	17 min
Jul 12, 9:18 AM CDT	Severe Thunderstorm Warning	ARX	Clayton	42 min
Jul 12, 9:44 AM CDT	Severe Thunderstorm Warning	ARX	Clayton	22 min
Jul 12, 10:12 AM CDT	Areal Flood Warning	ARX	Clayton	3 hr
Jul 12, 5:46 PM CDT	Severe Thunderstorm Warning	ARX	Fayette	26 min

Nearby

Tornado Warnings in Iowa, 2017 Every tornado warning in 2017 Tornadoes in 2017

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.