Alert archive / Iowa / Tornado Warnings in 2016

Tornado Warning 11, NWS La Crosse, WI

September 21, 2016Floyd County, Iowa

NWS La Crosse, WI issued this tornado warning at Sep 21, 2016, 5:20 PM CDT for Floyd County, Iowa. It was in force for 40 min. 2 reports 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, 5:20 PM CDT (22:20 UTC)
Expired
Sep 21, 2016, 6:00 PM CDT
In force
40 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 22:22 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, 5:33 PM CDTTSTM WND GST 703 W Marble Rock, IA.
Sep 21, 5:50 PM CDTTSTM WND DMG1 Se Marble Rock, IA2 TO 3 FOOT DIAMETER TREES DOWN.

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, 10.3 hours before the alert went out and 216 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.

377 
WFUS53 KARX 212220
TORARX
IAC067-212300-
/O.NEW.KARX.TO.W.0011.160921T2220Z-160921T2300Z/

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

THE NATIONAL WEATHER SERVICE IN LA CROSSE HAS ISSUED A

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

* UNTIL 600 PM CDT
    
* AT 520 PM CDT...A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A
  TORNADO WAS LOCATED NEAR MARBLE ROCK...OR 15 MILES NORTHWEST OF
  ALLISON...MOVING EAST AT 20 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...
  MARBLE ROCK AROUND 535 PM CDT. 
  CHARLES CITY AROUND 600 PM CDT. 

OTHER LOCATIONS IMPACTED BY THIS TORNADIC THUNDERSTORM INCLUDE
DOUGHERTY...OAKWOOD 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 4301 9302 4305 9263 4291 9265 4291 9303
TIME...MOT...LOC 2220Z 268DEG 17KT 4293 9297 

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

$$

AJ
1 follow-up statement
442 
WWUS53 KARX 212237
SVSARX

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

IAC067-212300-
/O.CON.KARX.TO.W.0011.000000T0000Z-160921T2300Z/
FLOYD IA-
537 PM CDT WED SEP 21 2016

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 600 PM CDT FOR SOUTHERN
FLOYD COUNTY...
    
AT 533 PM CDT...TRAINED WEATHER SPOTTERS REPORTED A BRIEF TORNADO
TOUCHDOWN 3 MILES WEST OF MARBLE ROCK...OR 13 MILES NORTH OF
ALLISON...MOVING EAST AT 20 MPH. THE STORM REMAINS CAPABLE OF
PRODUCING ADDITIONAL TORNADOES. 

HAZARD...DAMAGING TORNADOES...PING PONG BALL SIZE HAIL AND 70 MPH
         WIND GUSTS.

SOURCE...WEATHER SPOTTERS 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 TORNADO WILL BE NEAR...
  POWERSVILLE AROUND 600 PM CDT. 

OTHER LOCATIONS IMPACTED BY THIS TORNADIC THUNDERSTORM INCLUDE
OAKWOOD...COUNTY ROADS B 60 AND T 64...HIGHWAY 14 AND COUNTY ROAD B
60 AND ROSEVILLE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4305 9263 4291 9265 4291 9301 4302 9296
TIME...MOT...LOC 2233Z 268DEG 17KT 4293 9288 

TORNADO...OBSERVED
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, 5:52 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, 6:18 PM CDTTornado WarningARXFloyd42 min
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.