Alert archive / Iowa / Tornado Warnings in 2000

Tornado Warning 4, NWS Des Moines, IA

May 11, 2000Black Hawk County, Iowa

NWS Des Moines, IA issued this tornado warning at May 11, 2000, 7:44 PM CDT for Black Hawk County, Iowa. It was in force for 31 min. 3 reports came from inside the area while it was in force.

The area

The outline the Iowa Environmental Mesonet reconstructed for it; the warning itself named whole counties, with what was reported inside it.

The facts

Issued: May 11, 2000, 7:44 PM CDT (00:44 UTC)
Expired: May 11, 2000, 8:15 PM CDT
In force: 31 min
Issued by: NWS Des Moines, IA
Area: Whole counties; the outline is the Mesonet’s reconstruction

County Black Hawk County, IA

The radar

The Des Moines radar (KDMX), 147 km from the middle of the area, began a volume at 00:45 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 11, 7:45 PM CDT	Hail 1.5	Dunkerton, IA
May 11, 7:55 PM CDT	Tornado F2	Dunkerton, IA	Farm and several outbuildings destroyed
May 11, 8:20 PM CDT	Tornado F2	Dunkerton, IA	Two houses destroyed

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The watch it was issued in

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

Issued	Product	Office	Lasted
May 11, 6:45 PM CDT	Tornado Watch	SPC	5 hr

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 0.7 hours before the alert went out and 184 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: 2323 J/kg
Mixed-layer CIN: -39 J/kg
Mixed-layer LCL: 1261 m above ground
0-6 km bulk shear: 47 kt
0-1 km storm-relative helicity: 171 m²/s²
0-3 km storm-relative helicity: 218 m²/s²
Significant tornado parameter: 1.8
Supercell composite: 13.9

Open this sounding in Storm Lab

The text

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

000 
WFUS53 KDMX 120047
TORDSM
IAC013-120115-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
744 PM CDT THU MAY 11 2000

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

* TORNADO WARNING FOR...
  NORTHERN BLACK HAWK COUNTY IN NORTHEAST IOWA

* UNTIL 815 PM CDT

* NUMEROUS REPORTS OF TORNADOES WERE REPORTED.  ONE TORNADO WAS NEAR 
  DUNKERTON...15 MILES NORTHEAST OF WATERLOO...MOVING EAST AT 20     
  MPH.  A SECOND POSSIBLE TORNADO WAS 5 MILES NORTH OF WATERLOO      
  MOVING EAST AT 20 MPH. 

* SOME LOCATIONS THREATENED THROUGH 815 PM CDT...
  NORTH WATERLOO
  DUNKERTON
  DEWAR

THIS REPLACES THE PREVIOUS TORNADO WARNING.

THIS IS AN EXTREMELY DANGEROUS AND LIFE THREATENING SITUATION. IF YOU
ARE IN THE PATH OF THIS LARGE AND DEVASTATING TORNADO...ABANDON YOUR
MOBILE HOME AND VEHICLES...GET BELOW GROUND LEVEL IN ANY SHELTER YOU
HAVE. THIS TORNADO WILL LEVEL ANY RESIDENTAL 
BUILDING.

JOHNSON

LAT...LON 4263 9256 4243 9254 4243 9209 4262 9210
          4262 9219
&

JOHNSON
NNNN

The office that day

Everything else NWS Des Moines, IA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 11, 7:21 PM CDT	Tornado Warning	DMX	Black Hawk	29 min
May 11, 8:13 PM CDT	Tornado Warning	DMX	Black Hawk	32 min
May 11, 9:12 PM CDT	Flash Flood Warning	DMX	Black Hawk	3 hr
May 11, 10:51 PM CDT	Severe Thunderstorm Warning	DMX	Boone, Hamilton	29 min

Nearby

Tornado Warnings in Iowa, 2000 Every tornado warning in 2000 Tornadoes in 2000

Sources

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