Alert archive / Iowa / Tornado Warnings in 2008

Tornado Warning 42, NWS Sioux Falls, SD

June 11, 2008Clay County, Iowa

NWS Sioux Falls, SD issued this tornado warning at Jun 11, 2008, 7:20 PM CDT for Clay County, Iowa. It was in force for 25 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
Jun 11, 2008, 7:20 PM CDT (00:20 UTC)
Expired
Jun 11, 2008, 7:45 PM CDT
In force
25 min
Issued by
NWS Sioux Falls, SD
Area
Storm-based polygon

County Clay County, IA

The radar

The Sioux Falls radar (KFSD), 157 km from the middle of the area, began a volume at 00:20 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
Jun 11, 7:25 PM CDTTORNADO2 Nne Webb, IARAIN WRAPPED

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
Jun 11, 2:52 PM CDTTornado WatchSPC7 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 0.3 hours before the alert went out and 215 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 2008-06-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1641 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Omaha, NE at 00:00Z on 2008-06-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 232 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
1641 J/kg
Mixed-layer CIN
-16 J/kg
Mixed-layer LCL
1105 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
232 m²/s²
0-3 km storm-relative helicity
249 m²/s²
Significant tornado parameter
1.9
Supercell composite
8.7

Open this sounding in Storm Lab

The text

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

000 
WFUS53 KFSD 120020
TORFSD
IAC041-120045-
/O.NEW.KFSD.TO.W.0042.080612T0020Z-080612T0045Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
720 PM CDT WED JUN 11 2008

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* TORNADO WARNING FOR...
  SOUTHEASTERN CLAY COUNTY IN NORTHWEST IOWA

* UNTIL 745 PM CDT

* AT 720 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO 8 MILES
  SOUTHWEST OF WEBB...OR 16 MILES NORTH OF STORM LAKE...MOVING
  NORTHEAST AT 52 MPH.

* THE TORNADO WILL BE NEAR...
   WEBB AROUND 725 PM CDT...
   GILLETT GROVE AROUND 730 PM CDT...

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

A TORNADO WATCH REMAINS IN EFFECT UNTIL 1000 PM CDT WEDNESDAY EVENING
FOR NORTHWEST IOWA AND SOUTHWEST MINNESOTA AND NORTHEAST NEBRASKA AND
SOUTHEAST SOUTH DAKOTA.

LAT...LON 4292 9492 4291 9496 4291 9497 4292 9523
      4317 9493
TIME...MOT...LOC 0020Z 213DEG 45KT 4292 9507

$$

CHAPMAN
2 follow-up statements
000 
WWUS53 KFSD 120035
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
734 PM CDT WED JUN 11 2008

IAC041-120045-
/O.CON.KFSD.TO.W.0042.000000T0000Z-080612T0045Z/
CLAY IA-
734 PM CDT WED JUN 11 2008

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 745 PM CDT FOR
SOUTHEASTERN CLAY COUNTY...

AT 734 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A TORNADO.  THIS TORNADO WAS LOCATED 4 MILES EAST OF GILLETT
GROVE...OR 14 MILES SOUTHEAST OF SPENCER...MOVING NORTHEAST AT 56 
MPH.  IN ADDTION...AREAS SOUTHEAST OF WEBB CAN EXPECT DAMAGING WINDS 
TO 70 MPH.

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

A TORNADO WATCH REMAINS IN EFFECT UNTIL 1000 PM CDT WEDNESDAY EVENING
FOR NORTHWEST IOWA AND SOUTHWEST MINNESOTA AND NORTHEAST NEBRASKA AND
SOUTHEAST SOUTH DAKOTA.

LAT...LON 4292 9492 4291 9496 4291 9497 4292 9523
      4317 9493
TIME...MOT...LOC 0034Z 219DEG 48KT 4306 9489

$$

CHAPMAN
000 
WWUS53 KFSD 120045
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
745 PM CDT WED JUN 11 2008

IAC041-120055-
/O.EXP.KFSD.TO.W.0042.000000T0000Z-080612T0045Z/
CLAY IA-
745 PM CDT WED JUN 11 2008

...THE TORNADO WARNING FOR SOUTHEASTERN CLAY COUNTY HAS EXPIRED...

THE STORM HAS EXITED THE WARNED AREA.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 1000 PM CDT WEDNESDAY EVENING
FOR NORTHWEST IOWA AND SOUTHWEST MINNESOTA AND NORTHEAST NEBRASKA AND
SOUTHEAST SOUTH DAKOTA.

LAT...LON 4292 9492 4291 9496 4291 9497 4292 9523
      4317 9493
TIME...MOT...LOC 0045Z 219DEG 48KT 4317 9476

$$

CHAPMAN

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 11, 7:02 PM CDTTornado WarningFSDDickinson28 min
Jun 11, 7:15 PM CDTTornado WarningFSDBuena Vista30 min
Jun 11, 8:00 PM CDTTornado WarningFSDBuena Vista, Ida35 min
Jun 11, 8:49 PM CDTSevere Thunderstorm WarningFSDWoodbury26 min
Jun 11, 11:08 PM CDTRiver Flood WarningFSDCherokee5 days
Jun 12, 9:39 AM CDTRiver Flood WarningFSDClay, O'Brien60 hr
Jun 12, 9:39 AM CDTRiver Flood WarningFSDDickinson4 days

Nearby

Tornado Warnings in Iowa, 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.