Alert archive / Iowa / Severe Thunderstorm Warnings in 1994

Severe Thunderstorm Warning 147, NWS Des Moines, IA

July 20, 1994Johnson County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Jul 20, 1994, 1:52 AM CDT for Johnson County, Iowa. It was in force for 23 min.

The area

The counties it named.

The facts

Issued: Jul 20, 1994, 1:52 AM CDT (06:52 UTC)
Expired: Jul 20, 1994, 2:15 AM CDT
In force: 23 min
Issued by: NWS Des Moines, IA
Area: Whole counties

County Johnson County, IA

The nearest sounding before it

Minneapolis, MN (KSTC), launched 00:00Z, 6.9 hours before the alert went out and 389 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: 503 J/kg
Mixed-layer CIN: -73 J/kg
Mixed-layer LCL: 682 m above ground
0-6 km bulk shear: 51 kt
0-1 km storm-relative helicity: 14 m²/s²
0-3 km storm-relative helicity: 343 m²/s²
Significant tornado parameter: 0.8
Supercell composite: 7.4

Open this sounding in Storm Lab

The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

In the hours before

Special weather statement, Jul 20, 12:36 AM CDT, 1 hour 16 minutes before

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Special weather statement, Jul 20, 12:54 AM CDT, 58 minutes before

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Special weather statement, Jul 20, 12:55 AM CDT, 57 minutes before

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Special weather statement, Jul 20, 1:30 AM CDT, 22 minutes before

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Special weather statement, Jul 20, 1:34 AM CDT, 18 minutes before

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Special weather statement, Jul 20, 1:50 AM CDT, 2 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 19, 8:22 PM CDT	Tornado Warning	DMX	Chickasaw	30 min
Jul 19, 8:27 PM CDT	Tornado Warning	DMX	Howard	18 min
Jul 19, 8:32 PM CDT	Tornado Warning	DMX	Cerro Gordo	28 min
Jul 19, 8:47 PM CDT	Tornado Warning	DMX	Howard	28 min
Jul 19, 9:38 PM CDT	Severe Thunderstorm Warning	DMX	Winneshiek	52 min
Jul 19, 10:15 PM CDT	Severe Thunderstorm Warning	DMX	Allamakee	30 min
Jul 19, 10:27 PM CDT	Tornado Warning	DMX	Allamakee	37 min
Jul 20, 1:29 AM CDT	Severe Thunderstorm Warning	DMX	Johnson, Linn	31 min

Nearby

Severe Thunderstorm Warnings in Iowa, 1994 Every severe thunderstorm warning in 1994

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.