Alert archive / Iowa / Tornado Warnings in 2016

Tornado Warning 12, NWS La Crosse, WI

September 21, 2016Floyd County, Iowa

NWS La Crosse, WI issued this tornado warning at Sep 21, 2016, 6:18 PM CDT for Floyd County, Iowa. It was in force for 42 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
Sep 21, 2016, 6:18 PM CDT (23:18 UTC)
Expired
Sep 21, 2016, 7:00 PM CDT
In force
42 min
Issued by
NWS La Crosse, WI
Area
Storm-based polygon
Tornado
Radar indicated
Hail
1.5 in

County Floyd County, IA

The radar

The Des Moines radar (KDMX), 155 km from the middle of the area, began a volume at 23:17 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

TimeReportWhereRemark
Sep 21, 6:20 PM CDTTSTM WND DMG2 Se Marble Rock, IA2 TO 3 MACHINE SHEDS DESTROYED. RELAYED BY CHARLES CITY FD FROM MARBLE ROCK FD .

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

The nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 11.3 hours before the alert went out and 218 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-pSkew-T log-p diagram, Minneapolis, MN at 12:00Z on 2016-09-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 515 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Minneapolis, MN at 12:00Z on 2016-09-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 17 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
515 J/kg
Mixed-layer CIN
-331 J/kg
Mixed-layer LCL
738 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
17 m²/s²
0-3 km storm-relative helicity
136 m²/s²
Significant tornado parameter
0.0
Supercell composite
8.5

Open this sounding in Storm Lab

The text

As transmitted.

666 
WFUS53 KARX 212318
TORARX
IAC067-220000-
/O.NEW.KARX.TO.W.0012.160921T2318Z-160922T0000Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE LA CROSSE WI
618 PM CDT WED SEP 21 2016

THE NATIONAL WEATHER SERVICE IN LA CROSSE HAS ISSUED A

* TORNADO WARNING FOR...
  SOUTHWESTERN FLOYD COUNTY IN NORTH CENTRAL IOWA...

* UNTIL 700 PM CDT
    
* AT 617 PM CDT...A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A
  TORNADO WAS LOCATED 2 MILES SOUTH OF MARBLE ROCK...OR 11 MILES
  NORTH OF ALLISON...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 TORNADIC THUNDERSTORM WILL REMAIN OVER MAINLY RURAL AREAS OF
  SOUTHWESTERN FLOYD COUNTY...INCLUDING THE FOLLOWING LOCATIONS:
  HIGHWAY 14 AND COUNTY ROAD B 60 AND POWERSVILLE.

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 4300 9296 4301 9268 4291 9267 4291 9297
TIME...MOT...LOC 2317Z 273DEG 11KT 4291 9287 

TORNADO...RADAR INDICATED
HAIL...1.50IN

$$

AJ
1 follow-up statement
912 
WWUS53 KARX 212333 RRA
SVSARX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
633 PM CDT WED SEP 21 2016

IAC067-220000-
/O.CON.KARX.TO.W.0012.000000T0000Z-160922T0000Z/
FLOYD IA-
633 PM CDT WED SEP 21 2016

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 700 PM CDT FOR
SOUTHWESTERN FLOYD COUNTY...
    
AT 632 PM CDT...A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO
WAS LOCATED NEAR GREENE...OR 10 MILES SOUTH OF CHARLES CITY...MOVING
EAST AT 30 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. 

LOCATIONS IMPACTED INCLUDE...
MARBLE ROCK...HIGHWAY 14 AND COUNTY ROAD B 60 AND POWERSVILLE. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

HEAVY RAINFALL MAY HIDE THIS TORNADO. DO NOT WAIT TO SEE OR HEAR THE
TORNADO. TAKE COVER NOW!

&&

LAT...LON 4300 9293 4301 9268 4291 9267 4291 9294
TIME...MOT...LOC 2332Z 264DEG 25KT 4292 9273 

TORNADO...RADAR INDICATED
HAIL...1.50IN

$$

AJ

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 21, 6:44 AM CDTFlash Flood WarningARXAllamakee6 hr
Sep 21, 4:09 PM CDTSpecial Weather StatementARXFloyd51 min
Sep 21, 4:21 PM CDTSevere Thunderstorm WarningARXFloyd39 min
Sep 21, 4:47 PM CDTFlash Flood WarningARXFloyd4 hr
Sep 21, 5:03 PM CDTSevere Thunderstorm WarningARXFloyd57 min
Sep 21, 5:20 PM CDTTornado WarningARXFloyd40 min
Sep 21, 5:52 PM CDTSevere Thunderstorm WarningARXFloyd, Mitchell35 min
Sep 21, 6:01 PM CDTSevere Thunderstorm WarningARXFloyd44 min
Sep 21, 6:03 PM CDTFlash Flood WarningARXFloyd3 hr
Sep 21, 6:23 PM CDTFlash Flood WarningARXMitchell6 hr
Sep 21, 6:53 PM CDTTornado WarningARXChickasaw, Floyd32 min

Nearby

Tornado Warnings in Iowa, 2016Every tornado warning in 2016Tornadoes in 2016

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.