Alert archive / Iowa / Severe Thunderstorm Warnings in 2016

Severe Thunderstorm Warning 86, NWS La Crosse, WI

September 21, 2016Floyd County, Iowa

NWS La Crosse, WI issued this severe thunderstorm warning at Sep 21, 2016, 4:21 PM CDT for Floyd County, Iowa. It was in force for 39 min. 3 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, 4:21 PM CDT (21:21 UTC)
Expired
Sep 21, 2016, 5:00 PM CDT
In force
39 min
Issued by
NWS La Crosse, WI
Area
Storm-based polygon
Hail
1.0 in
Wind
70.0 mph

County Floyd County, IA

The radar

The La Crosse radar (KARX), 158 km from the middle of the area, began a volume at 21:21 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, 4:25 PM CDTTSTM WND DMGNora Springs, IA2 FOOT DIAMETER TREE DOWN ON HOUSE. RELAYED BY CHARLES CITY FD.
Sep 21, 5:06 PM CDTHAIL 1.5Rockford, IAREPORT VIA SOCIAL MEDIA.
Sep 21, 5:10 PM CDTTSTM WND DMG2 W Rockford, IATREES DOWN 2W OF ROCKFORD AS WELL AS IN NORA SPRINGS. WINDS ESTIMATED 60-70 MPH.

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, 9.4 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-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.

714 
WUUS53 KARX 212121
SVRARX
IAC067-212200-
/O.NEW.KARX.SV.W.0086.160921T2121Z-160921T2200Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE LA CROSSE WI
421 PM CDT WED SEP 21 2016

THE NATIONAL WEATHER SERVICE IN LA CROSSE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHERN FLOYD COUNTY IN NORTH CENTRAL IOWA...

* UNTIL 500 PM CDT

* AT 420 PM CDT...A SEVERE THUNDERSTORM WAS LOCATED NEAR NORA
  SPRINGS...OR 11 MILES EAST OF MASON CITY...MOVING NORTHEAST AT 20
  MPH.

  HAZARD...70 MPH WIND GUSTS AND QUARTER SIZE HAIL. 

  SOURCE...RADAR INDICATED AND FROM CHARLES CITY FIRE DEPARTMENT.

  IMPACT...HAIL DAMAGE TO VEHICLES IS EXPECTED. EXPECT CONSIDERABLE 
           TREE DAMAGE. WIND DAMAGE IS ALSO LIKELY TO MOBILE 
           HOMES...ROOFS...AND OUTBUILDINGS. 

* THIS SEVERE THUNDERSTORM WILL BE NEAR...
  RUDD AROUND 435 PM CDT. 
  FLOYD AROUND 455 PM CDT. 

OTHER LOCATIONS IMPACTED BY THIS SEVERE THUNDERSTORM INCLUDE
HOWARDVILLE...IDLEWILDE STATE PARK...COUNTY ROADS B 20 AND S 70 AND
COUNTY ROADS B 20 AND T 26.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
BUILDING.

TORRENTIAL RAINFALL IS OCCURRING WITH THIS STORM...AND MAY LEAD TO
FLASH FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED ROADWAYS.

&&

LAT...LON 4320 9302 4321 9301 4321 9256 4298 9302
TIME...MOT...LOC 2120Z 226DEG 15KT 4311 9297 

HAIL...1.00IN
WIND...70MPH
 
$$

AJ
2 follow-up statements
387 
WWUS53 KARX 212142
SVSARX

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

IAC067-212200-
/O.CON.KARX.SV.W.0086.000000T0000Z-160921T2200Z/
FLOYD IA-
442 PM CDT WED SEP 21 2016

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 500 PM CDT
FOR NORTHERN FLOYD COUNTY...

AT 441 PM CDT...A SEVERE THUNDERSTORM WAS LOCATED NEAR RUDD...OR 8
MILES SOUTHWEST OF OSAGE...MOVING NORTHEAST AT 15 MPH.

HAZARD...60 MPH WIND GUSTS AND NICKEL SIZE HAIL. 

SOURCE...LAW ENFORCEMENT. WIRES WERE REPORTED DOWN SOUTH OF NORA
         SPRINGS WHERE A 66 MPH MEASURED WIND GUST OCCURRED.

IMPACT...EXPECT DAMAGE TO ROOFS...SIDING...AND TREES. 

THIS SEVERE STORM WILL BE NEAR...
  FLOYD AROUND 455 PM CDT. 

OTHER LOCATIONS IMPACTED BY THIS SEVERE THUNDERSTORM INCLUDE
HOWARDVILLE...IDLEWILDE STATE PARK...COUNTY ROADS B 20 AND S 70 AND
COUNTY ROADS B 20 AND T 26.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
BUILDING.

TORRENTIAL RAINFALL IS OCCURRING WITH THIS STORM...AND MAY LEAD TO
FLASH FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED ROADWAYS.

&&

LAT...LON 4320 9302 4321 9301 4321 9256 4298 9302
TIME...MOT...LOC 2141Z 226DEG 15KT 4317 9288 

HAIL...0.88IN
WIND...60MPH
 
$$

AJ
590 
WWUS53 KARX 212159
SVSARX

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

IAC067-212206-
/O.EXP.KARX.SV.W.0086.000000T0000Z-160921T2200Z/
FLOYD IA-
459 PM CDT WED SEP 21 2016

...THE SEVERE THUNDERSTORM WARNING FOR NORTHERN FLOYD COUNTY WILL
EXPIRE AT 500 PM CDT...
                
THE STORM WHICH PROMPTED THE WARNING HAS DIMINISHED IN INTENSITY IN
PRODUCING HAIL OR SEVERE WIND GUSTS. THEREFORE THE SEVERE
THUNDERSTORM WARNING WILL BE ALLOWED TO EXPIRE. HOWEVER...A FLASH
FLOOD WARNING REMAINS IN EFFECT. ADDITIONALLY...THE STORMS OVER
NORTHWEST FLOYD COUNTY COULD INTENSIFY AGAIN REQUIRING ANOTHER
SEVERE THUNDERSTORM WARNING. CONTINUE TO MONITOR ALL WARNINGS AND
STATEMENTS FROM THE NATIONAL WEATHER SERVICE.

LAT...LON 4320 9302 4321 9301 4321 9256 4298 9302
TIME...MOT...LOC 2156Z 226DEG 15KT 4321 9283 

$$

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, 4:47 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, 6:18 PM CDTTornado WarningARXFloyd42 min
Sep 21, 6:23 PM CDTFlash Flood WarningARXMitchell6 hr
Sep 21, 6:53 PM CDTTornado WarningARXChickasaw, Floyd32 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2016Every severe thunderstorm warning 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.