Alert archive / Iowa / Tornado Warnings in 2008

Tornado Warning 9, NWS Sioux Falls, SD

May 1, 2008Nobles County, Minnesota; Lyon County, O'Brien County, Osceola County, Iowa

NWS Sioux Falls, SD issued this tornado warning at May 1, 2008, 7:39 PM CDT for Nobles County, Minnesota; Lyon County, O'Brien County, Osceola County, Iowa. It was in force for 36 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
May 1, 2008, 7:39 PM CDT (00:39 UTC)
Expired
May 1, 2008, 8:15 PM CDT
In force
36 min
Issued by
NWS Sioux Falls, SD
Area
Storm-based polygon

Counties Lyon County, IA, O'Brien County, IA, Osceola County, IA, Nobles County, MN

The radar

The Sioux Falls radar (KFSD), 80 km from the middle of the area, began a volume at 00:42 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.

The watch it was issued in

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

IssuedProductOfficeLasted
May 1, 4:34 PM CDTTornado WatchSPC5 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 0.7 hours before the alert went out and 231 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, Omaha, NE at 00:00Z on 2008-05-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Omaha, NE at 00:00Z on 2008-05-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -36 square meters per square second.19395878Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1405 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
-36 m²/s²
0-3 km storm-relative helicity
10 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.

000 
WFUS53 KFSD 020040
TORFSD
IAC119-141-143-MNC105-020115-
/O.NEW.KFSD.TO.W.0009.080502T0039Z-080502T0115Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
739 PM CDT THU MAY 1 2008

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* TORNADO WARNING FOR...
  EXTREME EASTERN LYON COUNTY IN NORTHWEST IOWA
  NORTHWESTERN OBRIEN COUNTY IN NORTHWEST IOWA
  WESTERN OSCEOLA COUNTY IN NORTHWEST IOWA
  SOUTHERN NOBLES COUNTY IN SOUTHWEST MINNESOTA

* UNTIL 815 PM CDT

* AT 739 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  A DEVELOPING SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO 
  NEAR ASHTON...OR 20 MILES SOUTHEAST OF ROCK RAPIDS...MOVING NORTH 
  AT 35 MPH.

* THE TORNADO WILL BE NEAR...
   SIBLEY...LITTLE ROCK AROUND 750 PM CDT...
   BIGELOW AROUND 805 PM CDT...
   RUSHMORE AROUND 810 PM CDT...
   WORTHINGTON AROUND 815 PM CDT...

THESE STORMS HAVE A HISTORY OF PRODUCING TORNADOES RAPIDLY.

THIS IS AN EXTREMELY DANGEROUS AND LIFE THREATENING SITUATION. TAKE
COVER NOW.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 1100 PM CDT THURSDAY EVENING
FOR NORTHWEST IOWA AND SOUTHWEST MINNESOTA AND SOUTHEASTERN SOUTH
DAKOTA.

LAT...LON 4312 9566 4322 9587 4326 9587 4327 9596
      4355 9595 4368 9589 4363 9547
TIME...MOT...LOC 0039Z 197DEG 38KT 4329 9582

$$

SCHUMACHER
1 follow-up statement
000 
WWUS53 KFSD 020103
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
803 PM CDT THU MAY 1 2008

IAC119-141-143-MNC105-020115-
/O.CON.KFSD.TO.W.0009.000000T0000Z-080502T0115Z/
OSCEOLA IA-LYON IA-OBRIEN IA-NOBLES MN-
803 PM CDT THU MAY 1 2008

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 815 PM CDT FOR SOUTHERN
NOBLES...NORTHWESTERN OBRIEN...EASTERN LYON AND WESTERN OSCEOLA
COUNTIES...

AT 803 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO 
INDICATE A LINE OF TORNADO PRODUCING STORMS. THESE TORNADO PRODUCING 
STORMS WERE LOCATED ALONG A LINE EXTENDING FROM 5 MILES WEST OF 
ASHTON TO 6 MILES WEST OF SANBORN...OR ALONG A LINE EXTENDING FROM 16
MILES SOUTHEAST OF ROCK RAPIDS TO 21 MILES NORTHEAST OF ORANGE 
CITY...MOVING NORTH AT 21 MPH.

TORNADO PRODUCING STORMS WILL BE NEAR...
   LITTLE ROCK AROUND 810 PM CDT...
   ASHTON...SIBLEY AROUND 815 PM CDT...

THIS IS AN EXTREMELY DANGEROUS AND LIFE THREATENING SITUATION. TAKE
COVER NOW.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 1100 PM CDT THURSDAY EVENING
FOR NORTHWEST IOWA AND SOUTHWEST MINNESOTA AND SOUTHEASTERN SOUTH
DAKOTA.

LAT...LON 4312 9566 4322 9587 4326 9587 4327 9596
      4355 9595 4368 9589 4363 9547
TIME...MOT...LOC 0103Z 181DEG 18KT 4333 9590 4323 9576

$$

PS

The office that day

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

IssuedProductOfficeCountiesLasted
May 1, 7:22 PM CDTTornado WarningFSDNobles, Rock23 min
May 1, 7:45 PM CDTTornado WarningFSDNobles, Rock30 min
May 1, 7:58 PM CDTSevere Thunderstorm WarningFSDLincoln, Lyon26 min
May 1, 8:16 PM CDTTornado WarningFSDNobles29 min
May 2, 3:49 PM CDTWind AdvisoryFSDCottonwood, Jackson, Lincoln, Lyon, Murray, Nobles and 2 more12 hr
May 2, 2:48 PM CDTRiver Flood WarningFSDPlymouth18 hr
May 2, 2:48 PM CDTRiver Flood WarningFSDClay, Dickinson7 days
May 2, 2:48 PM CDTRiver Flood WarningFSDBuena Vista7 days
May 2, 2:48 PM CDTRiver Flood WarningFSDSioux18 hr

Nearby

Tornado Warnings in Iowa, 2008Tornado Warnings in Minnesota, 2008Every tornado warning in 2008Tornadoes in 2008

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.