Alert archive / Iowa / Tornado Warnings in 1997

Tornado Warning 9, NWS Des Moines, IA

August 15, 1997Boone County, Dallas County, Iowa

NWS Des Moines, IA issued this tornado warning at Aug 15, 1997, 12:31 AM CDT for Boone County, Dallas County, Iowa. It was in force for 34 min. 4 reports came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued: Aug 15, 1997, 12:31 AM CDT (05:31 UTC)
Expired: Aug 15, 1997, 1:05 AM CDT
In force: 34 min
Issued by: NWS Des Moines, IA
Area: Whole counties

Counties Boone County, IA, Dallas County, IA

The radar

The Des Moines radar (KDMX), 26 km from the middle of the area, began a volume at 05:31 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
Aug 15, 12:35 AM CDT	Thunderstorm Wind 50	Perry, IA
Aug 15, 12:40 AM CDT	Thunderstorm Wind 50	Boone, IA
Aug 15, 12:45 AM CDT	Thunderstorm Wind 50	Woodward, IA
Aug 15, 12:57 AM CDT	Tornado F0	Woodward, IA

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 nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 5.5 hours before the alert went out and 207 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: 1810 J/kg
Mixed-layer CIN: -28 J/kg
Mixed-layer LCL: 837 m above ground
0-6 km bulk shear: 42 kt
0-1 km storm-relative helicity: 83 m²/s²
0-3 km storm-relative helicity: 101 m²/s²
Significant tornado parameter: 0.6
Supercell composite: 3.5

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KDSM 150530 RRA
TORDSM
IAC015-049-150605-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
1231 AM CDT FRI AUG 15 1997

* TORNADO WARNING FOR
  SOUTHERN BOONE COUNTY - CENTRAL IOWA
  NORTHERN DALLAS COUNTY - CENTRAL IOWA

* UNTIL 105 AM CDT
 
* SOME AREAS AFFECTED
    PERRY
    WOODWARD

* AT 1227 AM RADAR INDICATED A TORNADO 15 MILES NORTHWEST OF PERRY OR
  30 MILES NORTHWEST OF DES MOINES MOVING EAST AT 40 MPH.

* THE STORM WILL BE NEAR PERRY BY 1235 AM .

IF YOU ARE NEAR THIS DANGEROUS STORM...TAKE COVER IMMEDIATELY IN THE
LOWEST FLOOR AND INNER MOST ROOM OF A BUILDING.

THE SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR NORTHERN BOONE
COUNTY UNTIL 1250 AhM.


KUBINA

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 14, 11:00 PM CDT	Severe Thunderstorm Warning	DMX	Crawford	35 min
Aug 14, 11:58 PM CDT	Severe Thunderstorm Warning	DMX	Carroll, Greene	47 min
Aug 15, 12:23 AM CDT	Severe Thunderstorm Warning	DMX	Boone	27 min
Aug 15, 12:49 AM CDT	Severe Thunderstorm Warning	DMX	Polk, Story	31 min
Aug 15, 12:59 AM CDT	Severe Thunderstorm Warning	DMX	Hamilton, Story	36 min

Nearby

Tornado Warnings in Iowa, 1997 Every tornado warning in 1997 Tornadoes in 1997

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.