Alert archive / Iowa / Tornado Warnings in 1997

Tornado Warning 1, NWS Des Moines, IA

May 12, 1997Polk County, Iowa

NWS Des Moines, IA issued this tornado warning at May 12, 1997, 5:33 PM CDT for Polk County, Iowa. It was in force for 27 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
May 12, 1997, 5:33 PM CDT (22:33 UTC)
Expired
May 12, 1997, 6:00 PM CDT
In force
27 min
Issued by
NWS Des Moines, IA
Area
Whole counties

County Polk County, IA

The radar

The Des Moines radar (KDMX), 13 km from the middle of the area, began a volume at 22:33 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 nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 10.6 hours before the alert went out and 236 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 12:00Z on 1997-05-12Temperature 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°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Omaha, NE at 12:00Z on 1997-05-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 25 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
2060 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
25 m²/s²
0-3 km storm-relative helicity
57 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 
TTAA00 KDSM 122233 RRA
TORDSM
IAC153-122300-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
533 PM CDT MON MAY 12 1997

* TORNADO WARNING FOR
  EASTERN POLK COUNTY - CENTRAL IOWA

* UNTIL 600 PM CDT
 
* SOME AREAS AFFECTED
    ALTOONA
    MITCHELLVILLE

* AT 533 PM CDT STORM SPOTTERS REPORTED A TORNADO JUST EAST OF ANKENY
  MOVING SOUTHEAST AT 25 MPH MOVING SOUTHEAST AT 25 MPH.

* THE STORM WILL BE NEAR ALTOONA AND MITCHELLVILLE BY 545 PM.

IF YOU ARE NEAR THIS DANGEROUS STORM...TAKE COVER IMMEDIATELY IN THE
LOWEST FLOOR AND INNER MOST ROOM OF A BUILDING. A COLD AIR FUNNEL WAS
REPORTED TOUCHING THE GROUND JUST EAST OF ANKENY BY AN OFF DUTY NWS
EMPLOYEE.

PYTLAK
 

&

The office that day

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

IssuedProductOfficeCountiesLasted
May 12, 5:54 PM CDTTornado WarningDMXJasper31 min
May 12, 6:15 PM CDTTornado WarningDMXMarion35 min

Nearby

Tornado Warnings in Iowa, 1997Every tornado warning in 1997Tornadoes 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.