Alert archive / Iowa / Severe Thunderstorm Warnings in 1991

Severe Thunderstorm Warning 94, NWS Des Moines, IA

May 31, 1991Marshall County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at May 31, 1991, 10:59 AM CDT for Marshall County, Iowa. It was in force for 31 min.

The area

The counties it named.

The facts

Issued: May 31, 1991, 10:59 AM CDT (15:59 UTC)
Expired: May 31, 1991, 11:30 AM CDT
In force: 31 min
Issued by: NWS Des Moines, IA
Area: Whole counties

County Marshall County, IA

The nearest sounding before it

Omaha, NE (KOVN), launched 12:00Z, 4.0 hours before the alert went out and 291 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: 2211 J/kg
Mixed-layer CIN: -140 J/kg
Mixed-layer LCL: 739 m above ground
0-6 km bulk shear: 39 kt
0-1 km storm-relative helicity: 339 m²/s²
0-3 km storm-relative helicity: 312 m²/s²
Significant tornado parameter: 1.2
Supercell composite: 9.2

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, May 31, 8:22 AM CDT, 2 hours 37 minutes before

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Special weather statement, May 31, 9:04 AM CDT, 1 hour 55 minutes before

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Special weather statement, May 31, 9:56 AM CDT, 1 hour 3 minutes before

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Special weather statement, May 31, 9:58 AM CDT, 1 hour 1 minute before

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Special weather statement, May 31, 10:53 AM CDT, 6 minutes before

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Special weather statement, May 31, 10:58 AM CDT, 1 minute before

IAZ002-003-007-311630-

SPECIAL WEATHER STATEMENT AND AREA WEATHER UPDATE
NATIONAL WEATHER SERVICE WATERLOO IA
1050 AM CDT FRI MAY 31 1991

AT 1050 AM CDT TWO LINES OF SHOWERS AND THUNDERSTORMS WERE
LOCATED IN NORTHEAST IOWA...THE FIRST WAS LOCATED FROM NEAR
PRARIE DU CHEIN WISCONSIN 30 MILES SOUTH OF LACROSS TO CEDAR
RAPIDS IOWA...THE SECOND WAS LOCATED FROM CLARKSVILLE...20 MILES
NORTHWEST OF WATERLOO TO ELDORA...35 MILES SOUTHWEST OF WATERLOO.
THESE THUNDERSTORM LINES WERE MOVING EAST AT 35 MILES AN HOUR.
THESE THUNDERSTORMS WERE PRODUCING BRIEF HEAVY RAIN...1.31 INCHES
AT WATERLOO...1.53 AT WELLSBURG...1.75 IN SOUTHERN FRANKLIN COUNTY.
FREQUENT LIGHTNING ALSO ACCOMPANIED THE THUNDERSTORMS WITH EVEN
SOME HAIL REPORTED AT 3/4 INCH.

FOR THE REMAINDER OF THE MORNING NORTHEAST IOWA CAN EXPECT SHOWERS
AND THUNDERSTORMS AT TIMES WITH TEMPERATURES IN THE MIDDLE 70S TO
NEAR 80 DEGREES.  THE WINDS WILL BE SOUTH 5 TO 10 MILES AN HOUR...
HOWEVER THEY WILL BE STRONG AND GUSTY NEAR THUNDERSTORMS.

The office that day

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

Issued	Product	Office	Counties	Lasted
May 31, 5:06 AM CDT	Severe Thunderstorm Warning	DMX	Hamilton, Hardin	54 min
May 31, 5:34 AM CDT	Severe Thunderstorm Warning	DMX	Franklin	56 min
May 31, 8:22 AM CDT	Severe Thunderstorm Warning	DMX	Bremer, Butler	68 min
May 31, 9:23 AM CDT	Severe Thunderstorm Warning	DMX	Buchanan	67 min
May 31, 12:36 PM CDT	Severe Thunderstorm Warning	DMX	Polk	39 min
May 31, 12:50 PM CDT	Flash Flood Warning	DMX	Benton, Linn	3 hr
May 31, 2:51 PM CDT	Flash Flood Warning	DMX	Iowa, Johnson	3 hr
May 31, 2:51 PM CDT	Flash Flood Warning	DMX	Poweshiek	3 hr

Nearby

Severe Thunderstorm Warnings in Iowa, 1991 Every severe thunderstorm warning in 1991

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.