Alert archive / South Dakota / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 80, NWS Sioux Falls, SD

May 21, 2011Lyon County, Iowa; Lincoln County, Minnehaha County, South Dakota; Rock County, Minnesota

NWS Sioux Falls, SD issued this severe thunderstorm warning at May 21, 2011, 8:16 PM CDT for Lyon County, Iowa; Lincoln County, Minnehaha County, South Dakota; Rock County, Minnesota. It was in force for 29 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
May 21, 2011, 8:16 PM CDT (01:16 UTC)
Expired
May 21, 2011, 8:45 PM CDT
In force
29 min
Issued by
NWS Sioux Falls, SD
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Lyon County, IA, Rock County, MN, Lincoln County, SD, Minnehaha County, SD

The radar

The Sioux Falls radar (KFSD), 8 km from the middle of the area, began a volume at 01:19 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
May 21, 8:17 PM CDTTSTM WND DMG2 Se Sioux Falls, SDTREE PUSHED DOWN ACROSS ROADWAY BY STRONG WIND GUSTS
May 21, 8:19 PM CDTTSTM WND DMG2 Se Sioux Falls, SDROOF REPORTED RIPPED OFF IN TOWN
May 21, 8:35 PM CDTHAIL 0.75Brandon, SDALSO 45 MPH WIND GUSTS AND HEAVY RAIN

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

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
May 21, 2:25 PM CDTSevere Thunderstorm WatchSPC10 hr

The nearest sounding before it

Aberdeen, SD (KABR), launched 00:00Z, 1.3 hours before the alert went out and 204 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, Aberdeen, SD at 00:00Z on 2011-05-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 361 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, Aberdeen, SD at 00:00Z on 2011-05-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -7 square meters per square second.1939Sfc1 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
361 J/kg
Mixed-layer CIN
-23 J/kg
Mixed-layer LCL
1036 m above ground
0-6 km bulk shear
7 kt
0-1 km storm-relative helicity
-7 m²/s²
0-3 km storm-relative helicity
-50 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

454 
WUUS53 KFSD 220116
SVRFSD
IAC119-MNC133-SDC083-099-220145-
/O.NEW.KFSD.SV.W.0080.110522T0116Z-110522T0145Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
816 PM CDT SAT MAY 21 2011

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  WESTERN LYON COUNTY IN NORTHWEST IOWA...
  SOUTHWESTERN ROCK COUNTY IN SOUTHWEST MINNESOTA...
  NORTH CENTRAL LINCOLN COUNTY IN SOUTHEAST SOUTH DAKOTA...
  EASTERN MINNEHAHA COUNTY IN SOUTHEAST SOUTH DAKOTA...

* UNTIL 845 PM CDT

* AT 815 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE
  TRACKING A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE
  HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS
  LOCATED NEAR CANTON...AND MOVING NORTH AT 55 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  SOUTHEASTERN SIOUX FALLS AROUND 820 PM CDT...
  ROWENA AND EASTERN SIOUX FALLS AROUND 825 PM CDT...
  BRANDON AND VALLEY SPRINGS AROUND 830 PM CDT...
  PALISADES STATE PARK AROUND 835 PM CDT...
  GARRETSON AND BALTIC AROUND 840 PM CDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 60 MILES PER
HOUR...DESTRUCTIVE HAIL...DEADLY LIGHTNING...AND VERY HEAVY RAIN. FOR
YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF YOUR
HOME OR BUSINESS. HEAVY RAINS FLOOD ROADS QUICKLY SO DO NOT DRIVE
INTO AREAS WHERE WATER COVERS THE ROAD.

&&

LAT...LON 4377 9677 4375 9638 4328 9647 4330 9679
TIME...MOT...LOC 0115Z 187DEG 47KT 4341 9662
WIND...HAIL 60MPH 1.00IN

$$

HANKO
2 follow-up statements
745 
WWUS53 KFSD 220123
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
823 PM CDT SAT MAY 21 2011

IAC119-MNC133-SDC083-099-220145-
/O.CON.KFSD.SV.W.0080.000000T0000Z-110522T0145Z/
LYON IA-ROCK MN-MINNEHAHA SD-LINCOLN SD-
823 PM CDT SAT MAY 21 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR NORTH CENTRAL
LINCOLN...EASTERN MINNEHAHA...SOUTHWESTERN ROCK AND WESTERN LYON
COUNTIES UNTIL 845 PM CDT...

AT 822 PM CDT...TRAINED WEATHER SPOTTERS REPORTED A SEVERE
THUNDERSTORM PRODUCING QUARTER SIZE HAIL...AND DESTRUCTIVE WINDS IN
EXCESS OF 70 MPH.  THIS STORM WAS LOCATED NEAR HARRISBURG...OR 9
MILES SOUTHEAST OF SIOUX FALLS...MOVING NORTH AT 55 MPH.

IN ADDITION...AT 819 PM WINDS CAPABLE OF TEARING OFF A ROOF WERE 
REPORTED IN EASTERN SIOUX FALLS WITH THIS STORM.

THE SEVERE THUNDERSTORM WILL BE NEAR...
  EASTERN SIOUX FALLS AT 825 PM CDT...
  BRANDON AND VALLEY SPRINGS AROUND 830 PM CDT...
  PALISADES STATE PARK...GARRETSON AND BALTIC AROUND 840 PM CDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 60 MILES PER
HOUR...DESTRUCTIVE HAIL...DEADLY LIGHTNING...AND VERY HEAVY RAIN. FOR
YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF YOUR
HOME OR BUSINESS. HEAVY RAINS FLOOD ROADS QUICKLY SO DO NOT DRIVE
INTO AREAS WHERE WATER COVERS THE ROAD.

&&

LAT...LON 4377 9677 4375 9638 4328 9647 4330 9679
TIME...MOT...LOC 0122Z 187DEG 46KT 4348 9660
WIND...HAIL 70MPH 1.00IN

$$

HANKO
987 
WWUS53 KFSD 220132
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
832 PM CDT SAT MAY 21 2011

IAC119-MNC133-SDC083-099-220145-
/O.CON.KFSD.SV.W.0080.000000T0000Z-110522T0145Z/
LYON IA-ROCK MN-MINNEHAHA SD-LINCOLN SD-
832 PM CDT SAT MAY 21 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR NORTH CENTRAL
LINCOLN...EASTERN MINNEHAHA...SOUTHWESTERN ROCK AND NORTHWESTERN LYON
COUNTIES UNTIL 845 PM CDT...

AT 832 PM CDT...TRAINED WEATHER SPOTTERS REPORTED A SEVERE
THUNDERSTORM PRODUCING QUARTER SIZE HAIL...AND DESTRUCTIVE WINDS IN
EXCESS OF 70 MPH.  THIS STORM WAS LOCATED NEAR ROWENA...OR 8 MILES
EAST OF SIOUX FALLS...MOVING NORTH AT 45 MPH.

THE SEVERE THUNDERSTORM WILL BE NEAR...
  PALISADES STATE PARK AROUND 840 PM CDT...
  GARRETSON AROUND 845 PM CDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 60 MILES PER
HOUR...DESTRUCTIVE HAIL...DEADLY LIGHTNING...AND VERY HEAVY RAIN. FOR
YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF YOUR
HOME OR BUSINESS. HEAVY RAINS FLOOD ROADS QUICKLY SO DO NOT DRIVE
INTO AREAS WHERE WATER COVERS THE ROAD.

THIS STORM HAS A HISTORY OF PRODUCING DAMAGING WIND. THIS IS AN
EXTREMELY DANGEROUS SITUATION. SEEK SHELTER NOW INSIDE A STURDY
STRUCTURE AND STAY AWAY FROM WINDOWS.

&&

LAT...LON 4346 9644 4346 9671 4377 9677 4375 9638
TIME...MOT...LOC 0132Z 191DEG 40KT 4356 9656
WIND...HAIL 70MPH 1.00IN

$$
HANKO

The office that day

Everything else NWS Sioux Falls, SD issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 21, 7:49 PM CDTSevere Thunderstorm WarningFSDLyon26 min
May 21, 7:05 PM CDTSevere Thunderstorm WarningFSDClay, Turner25 min
May 21, 7:28 PM CDTSevere Thunderstorm WarningFSDClay, Lincoln, Turner32 min
May 21, 7:38 PM CDTSevere Thunderstorm WarningFSDClay, Union37 min
May 21, 8:39 PM CDTSevere Thunderstorm WarningFSDMinnehaha, Moody36 min
May 22, 10:52 AM CDTRiver Flood WarningFSDMinnehaha, Moody22 hr
May 21, 8:29 PM CDTSevere Thunderstorm WarningFSDJackson31 min
May 21, 8:57 PM CDTSevere Thunderstorm WarningFSDCottonwood, Jackson33 min
May 21, 9:17 PM CDTSevere Thunderstorm WarningFSDCottonwood, Jackson43 min
May 21, 9:32 PM CDTSevere Thunderstorm WarningFSDCottonwood13 min
May 21, 9:58 PM CDTSevere Thunderstorm WarningFSDCottonwood32 min

Nearby

Severe Thunderstorm Warnings in South Dakota, 2011Severe Thunderstorm Warnings in Iowa, 2011Severe Thunderstorm Warnings in Minnesota, 2011Every severe thunderstorm warning in 2011

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.