Alert archive / Iowa / Tornado Warnings in 2009

Tornado Warning 7, NWS Sioux Falls, SD

May 6, 20094 counties in Iowa

NWS Sioux Falls, SD issued this tornado warning at May 6, 2009, 5:23 PM CDT for 4 counties in Iowa. It was in force for 52 min. 6 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 6, 2009, 5:23 PM CDT (22:23 UTC)
Expired
May 6, 2009, 6:15 PM CDT
In force
52 min
Issued by
NWS Sioux Falls, SD
Area
Storm-based polygon

Counties Clay County, IA, Dickinson County, IA, O'Brien County, IA, Osceola County, IA

The radar

The Sioux Falls radar (KFSD), 113 km from the middle of the area, began a volume at 22:25 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 6, 5:25 PM CDTHAIL 0.757 S Ocheyedan, IAIN MAY CITY
May 6, 5:32 PM CDTHAIL 1.757 S Ocheyedan, IA
May 6, 5:45 PM CDTHAIL 15 N Hartley, IA
May 6, 5:45 PM CDTHAIL 16 E Melvin, IASHERIFF OFFICE IN SIBLEY IA...REPORTS QUARTER SIZE HAIL 3 MI WEST AND 1 MI NORTH OF MAY CITY AND DIME SIZE HAIL IN MAY CITY.
May 6, 5:50 PM CDTHAIL 1.752 Ne Hartley, IA
May 6, 6:01 PM CDTHAIL 13 Wnw Everly, 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 225 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 2009-05-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1 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 2009-05-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 70 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
1 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1939 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
70 m²/s²
0-3 km storm-relative helicity
120 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

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

000 
WFUS53 KFSD 062223
TORFSD
IAC041-059-141-143-062315-
/O.NEW.KFSD.TO.W.0007.090506T2223Z-090506T2315Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
523 PM CDT WED MAY 6 2009

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* TORNADO WARNING FOR...
  NORTHWESTERN CLAY COUNTY IN NORTHWEST IOWA
  SOUTHWESTERN DICKINSON COUNTY IN NORTHWEST IOWA
  NORTHEASTERN OBRIEN COUNTY IN NORTHWEST IOWA
  EASTERN OSCEOLA COUNTY IN NORTHWEST IOWA

* UNTIL 615 PM CDT

* AT 521 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS
  STORM WAS LOCATED NEAR OCHEYEDAN...OR 20 MILES SOUTH OF
  WORTHINGTON...AND MOVING SOUTHEAST AT 15 MPH.

* THIS TORNADIC STORM WILL BE NEAR...
   HARTLEY AROUND 605 PM CDT...
   EVERLY...MONETA AROUND 615 PM CDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF IN MOBILE HOMES OR VEHICLES...EVACUATE THEM AND GET INSIDE A
STURDY SHELTER. IF NO SHELTER IS AVAILABLE...LIE FLAT IN THE NEAREST
DITCH OR OTHER LOW SPOT AND COVER YOUR HEAD WITH YOUR HANDS.

IN ADDITION TO THE TORNADO...THIS STORM IS CAPABLE OF PRODUCING 
QUARTER SIZE HAIL AND DESTRUCTIVE STRAIGHT LINE WINDS.

&&

LAT...LON 4325 9517 4310 9540 4336 9569 4348 9551
TIME...MOT...LOC 2223Z 325DEG 12KT 4334 9550

$$

BT
5 follow-up statements
000 
WWUS53 KFSD 062231
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
531 PM CDT WED MAY 6 2009

IAC041-059-141-143-062315-
/O.CON.KFSD.TO.W.0007.000000T0000Z-090506T2315Z/
DICKINSON IA-OSCEOLA IA-OBRIEN IA-CLAY IA-
531 PM CDT WED MAY 6 2009

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 615 PM CDT FOR
NORTHWESTERN CLAY...NORTHEASTERN OBRIEN...EASTERN OSCEOLA AND
SOUTHWESTERN DICKINSON COUNTIES...

AT 526 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A TORNADO. THIS TORNADO WAS LOCATED 6 MILES SOUTH OF
OCHEYEDAN...OR 20 MILES WEST OF SPIRIT LAKE...MOVING SOUTHEAST AT 15
MPH.

THE TORNADO WILL BE NEAR...
HARTLEY AROUND 605 PM CDT...
EVERLY AND MONETA AROUND 615 PM CDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IN ADDITION TO THE TORNADO...THIS STORM IS CAPABLE OF PRODUCING 
GOLFBALL SIZE HAIL AND DESTRUCTIVE STRAIGHT LINE WINDS.

AT 531 PM...GOLFBALL SIZED HAIL WAS REPORTED ONE MILE NORTH OF MAY 
CITY WITH THIS STORM.

&&

LAT...LON 4325 9517 4310 9540 4336 9569 4348 9551
TIME...MOT...LOC 2230Z 325DEG 12KT 4332 9548

$$

BT
000 
WWUS53 KFSD 062235
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
535 PM CDT WED MAY 6 2009

IAC041-059-141-143-062315-
/O.CON.KFSD.TO.W.0007.000000T0000Z-090506T2315Z/
DICKINSON IA-OSCEOLA IA-OBRIEN IA-CLAY IA-
535 PM CDT WED MAY 6 2009

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 615 PM CDT FOR
NORTHWESTERN CLAY...NORTHEASTERN OBRIEN...EASTERN OSCEOLA AND
SOUTHWESTERN DICKINSON COUNTIES...

AT 531 PM CDT...A TORNADO WAS REPORTED. THIS TORNADO WAS LOCATED 8
MILES SOUTH OF OCHEYEDAN...OR 21 MILES NORTHWEST OF SPENCER...MOVING
SOUTHEAST AT 15 MPH.

THE TORNADO WILL BE NEAR...
HARTLEY AROUND 605 PM CDT...
MONETA AND EVERLY AROUND 615 PM CDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IN ADDITION TO THE TORNADO...THIS STORM IS CAPABLE OF PRODUCING 
GOLFBALL SIZE HAIL AND DESTRUCTIVE STRAIGHT LINE WINDS.

IF YOU ARE CAUGHT OUTSIDE...SEEK SHELTER IN A NEARBY REINFORCED
BUILDING. AS A LAST RESORT...SEEK SHELTER IN A CULVERT...DITCH OR LOW
SPOT AND COVER YOUR HEAD WITH YOUR HANDS.

THIS IS A DANGEROUS STORM. IF YOU ARE IN THE PATH OF THIS 
STORM...SEEK SHELTER IMMEDIATELY.  RADAR HAS INDICATED THIS STORM IS 
INCREASING IN INTENSITY. 

&&

LAT...LON 4325 9517 4310 9540 4336 9569 4348 9551
TIME...MOT...LOC 2234Z 336DEG 13KT 4330 9549

$$

BT
000 
WWUS53 KFSD 062244
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
544 PM CDT WED MAY 6 2009

IAC041-059-141-143-062315-
/O.CON.KFSD.TO.W.0007.000000T0000Z-090506T2315Z/
DICKINSON IA-OSCEOLA IA-OBRIEN IA-CLAY IA-
544 PM CDT WED MAY 6 2009

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 615 PM CDT FOR
NORTHWESTERN CLAY...NORTHEASTERN OBRIEN...EASTERN OSCEOLA AND
SOUTHWESTERN DICKINSON COUNTIES...

AT 541 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A TORNADO. THIS TORNADO WAS LOCATED NEAR HARTLEY...OR 18
MILES NORTHWEST OF SPENCER...MOVING SOUTHEAST AT 20 MPH.

THE TORNADO WILL BE NEAR...
HARTLEY AROUND 555 PM CDT...
MONETA AND EVERLY AROUND 610 PM CDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IN ADDITION TO THE TORNADO...THIS STORM IS CAPABLE OF PRODUCING 
GOLFBALL SIZE HAIL AND DESTRUCTIVE STRAIGHT LINE WINDS.

IF YOU ARE CAUGHT OUTSIDE...SEEK SHELTER IN A NEARBY REINFORCED
BUILDING. AS A LAST RESORT...SEEK SHELTER IN A CULVERT...DITCH OR LOW
SPOT AND COVER YOUR HEAD WITH YOUR HANDS.

&&

LAT...LON 4325 9517 4310 9540 4336 9569 4348 9551
TIME...MOT...LOC 2243Z 337DEG 16KT 4325 9546

$$


BT
000 
WWUS53 KFSD 062250
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
550 PM CDT WED MAY 6 2009

IAC041-059-141-143-062315-
/O.CON.KFSD.TO.W.0007.000000T0000Z-090506T2315Z/
DICKINSON IA-OSCEOLA IA-OBRIEN IA-CLAY IA-
550 PM CDT WED MAY 6 2009

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 615 PM CDT FOR
NORTHWESTERN CLAY...NORTHEASTERN OBRIEN...EASTERN OSCEOLA AND
SOUTHWESTERN DICKINSON COUNTIES...

AT 546 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A TORNADO. THIS TORNADO WAS LOCATED NEAR HARTLEY...OR 16
MILES WEST OF SPENCER...MOVING SOUTHEAST AT 20 MPH.

THE TORNADO WILL BE NEAR...
HARTLEY AROUND 555 PM CDT...
EVERLY AND MONETA AROUND 610 PM CDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IN ADDITION TO THE TORNADO...THIS STORM IS CAPABLE OF PRODUCING 
GOLFBALL
SIZE HAIL AND DESTRUCTIVE STRAIGHT LINE WINDS.

IF IN MOBILE HOMES OR VEHICLES...EVACUATE THEM AND GET INSIDE A
STURDY SHELTER. IF NO SHELTER IS AVAILABLE...LIE FLAT IN THE NEAREST
DITCH OR OTHER LOW SPOT AND COVER YOUR HEAD WITH YOUR HANDS.

THIS STORM CONTINUES TO EXHIBIT STRONG ROTATION.  IF YOU ARE IN THE 
PATH OF THIS STORM...SEEK SHELTER NOW

&&

LAT...LON 4325 9517 4310 9540 4336 9569 4348 9551
TIME...MOT...LOC 2249Z 337DEG 16KT 4322 9545

$$


BT
000 
WWUS53 KFSD 062252
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
552 PM CDT WED MAY 6 2009

IAC041-059-141-143-062315-
/O.CON.KFSD.TO.W.0007.000000T0000Z-090506T2315Z/
DICKINSON IA-OSCEOLA IA-OBRIEN IA-CLAY IA-
552 PM CDT WED MAY 6 2009

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 615 PM CDT FOR
NORTHWESTERN CLAY...NORTHEASTERN OBRIEN...EXTREME SOUTHEASTERN
OSCEOLA AND EXTREME SOUTHWESTERN DICKINSON COUNTIES...

AT 551 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A TORNADO. THIS TORNADO WAS LOCATED NEAR HARTLEY...OR 15
MILES WEST OF SPENCER...MOVING SOUTHEAST AT 20 MPH.

THE TORNADO WILL BE NEAR...
EVERLY AND MONETA AROUND 610 PM CDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IN ADDITION TO THE TORNADO...THIS STORM IS CAPABLE OF PRODUCING 
GOLFBALL SIZE HAIL AND DESTRUCTIVE STRAIGHT LINE WINDS.

IF IN MOBILE HOMES OR VEHICLES...EVACUATE THEM AND GET INSIDE A
STURDY SHELTER. IF NO SHELTER IS AVAILABLE...LIE FLAT IN THE NEAREST
DITCH OR OTHER LOW SPOT AND COVER YOUR HEAD WITH YOUR HANDS.

&&

LAT...LON 4325 9556 4326 9539 4318 9528 4310 9540
TIME...MOT...LOC 2253Z 337DEG 16KT 4321 9544

$$

BT

The office that day

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

IssuedProductOfficeCountiesLasted
May 6, 9:34 AM CDTSevere Thunderstorm WarningFSDDickinson26 min
May 6, 2:34 PM CDTSevere Thunderstorm WarningFSDPlymouth, Woodbury41 min
May 6, 3:07 PM CDTSevere Thunderstorm WarningFSDWoodbury23 min
May 6, 3:30 PM CDTSevere Thunderstorm WarningFSDWoodbury15 min
May 6, 5:15 PM CDTSevere Thunderstorm WarningFSDClay, Dickinson, Osceola45 min
May 6, 5:54 PM CDTTornado WarningFSDClay, O'Brien35 min
May 6, 6:23 PM CDTSevere Thunderstorm WarningFSDBuena Vista, Clay19 min

Nearby

Tornado Warnings in Iowa, 2009Every tornado warning in 2009Tornadoes in 2009

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.