Alert archive / Iowa / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 20, NWS La Crosse, WI

May 3, 2012Floyd County, Mitchell County, Iowa

NWS La Crosse, WI issued this severe thunderstorm warning at May 3, 2012, 5:24 PM CDT for Floyd County, Mitchell County, Iowa. It was in force for 20 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: May 3, 2012, 5:24 PM CDT (22:24 UTC)
Expired: May 3, 2012, 5:44 PM CDT
In force: 20 min
Issued by: NWS La Crosse, WI
Area: Storm-based polygon
Hail: 1.0 in
Wind: 50.0 mph

Counties Floyd County, IA, Mitchell County, IA

The radar

The La Crosse radar (KARX), 153 km from the middle of the area, began a volume at 22:28 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
May 3, 5:32 PM CDT	HAIL 0.25	5 Nne Nora Springs, IA

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, 10.4 hours before the alert went out and 194 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: 1755 J/kg
Mixed-layer CIN: -7 J/kg
Mixed-layer LCL: 521 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 27 m²/s²
0-3 km storm-relative helicity: 33 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 0.3

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

766 
WUUS53 KARX 032224
SVRARX
IAC067-131-032300-
/O.NEW.KARX.SV.W.0020.120503T2224Z-120503T2300Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE LA CROSSE WI
524 PM CDT THU MAY 3 2012

THE NATIONAL WEATHER SERVICE IN LA CROSSE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHWESTERN FLOYD COUNTY IN NORTH CENTRAL IOWA...
  SOUTHWESTERN MITCHELL COUNTY IN NORTH CENTRAL IOWA...

* UNTIL 600 PM CDT

* AT 518 PM CDT...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM
  LOCATED 4 MILES NORTHEAST OF MASON CITY...MOVING EAST AT 30 MPH. 
  THIS STORM CAN PRODUCE QUARTER SIZE HAIL. EMERGENCY MANAGEMENT 
  OFFICIALS HAVE ALREADY REPORTED QUARTER SIZE HAIL WITH THIS STORM.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  NORA SPRINGS AROUND 530 PM...
  ROCK CREEK AROUND 535 PM...
  RUDD AROUND 540 PM...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF YOU ARE IN THE PATH OF THIS STORM...PREPARE IMMEDIATELY FOR LARGE
HAIL. SEEK SHELTER NOW INSIDE A STURDY STRUCTURE AND STAY AWAY FROM
WINDOWS.

&&

LAT...LON 4323 9278 4317 9279 4316 9281 4310 9284
      4314 9303 4325 9303
TIME...MOT...LOC 2223Z 278DEG 24KT 4319 9307
WIND...HAIL <50MPH 1.00IN

$$

AJ

1 follow-up statement

726 
WWUS53 KARX 032244
SVSARX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
544 PM CDT THU MAY 3 2012

IAC067-131-032254-
/O.CAN.KARX.SV.W.0020.000000T0000Z-120503T2300Z/
MITCHELL IA-FLOYD IA-
544 PM CDT THU MAY 3 2012

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN FLOYD AND
SOUTHWESTERN MITCHELL COUNTIES IS CANCELLED...

THE STORM WHICH PROMPTED THE WARNING HAS WEAKENED BELOW SEVERE
LIMITS...AND NO LONGER POSES AN IMMEDIATE THREAT TO LIFE OR PROPERTY.

LAT...LON 4323 9278 4317 9279 4316 9281 4310 9284
      4314 9303 4325 9303
TIME...MOT...LOC 2244Z 278DEG 24KT 4317 9288

$$

AJ

The office that day

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

Issued	Product	Office	Counties	Lasted
May 3, 5:44 AM CDT	Severe Thunderstorm Warning	ARX	Chickasaw, Floyd, Howard, Mitchell	31 min
May 3, 6:11 AM CDT	Severe Thunderstorm Warning	ARX	Chickasaw, Howard, Winneshiek	34 min
May 3, 6:43 AM CDT	Severe Thunderstorm Warning	ARX	Allamakee, Howard, Winneshiek	47 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2012 Every severe thunderstorm warning in 2012

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.