Alert archive / Iowa / Severe Thunderstorm Warnings in 1991

Severe Thunderstorm Warning 30, NWS Des Moines, IA

April 26, 1991Polk County, Warren County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Apr 26, 1991, 9:46 PM CDT for Polk County, Warren County, Iowa. It was in force for 44 min.

The area

The counties it named.

The facts

Issued: Apr 26, 1991, 9:46 PM CDT (02:46 UTC)
Expired: Apr 26, 1991, 10:30 PM CDT
In force: 44 min
Issued by: NWS Des Moines, IA
Area: Whole counties

Counties Polk County, IA, Warren County, IA

The nearest sounding before it

Topeka, KS (KTOP), launched 00:00Z, 2.8 hours before the alert went out and 330 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: NaN m above ground
0-6 km bulk shear: 79 kt
0-1 km storm-relative helicity: 409 m²/s²
0-3 km storm-relative helicity: 485 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 17.2

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, Apr 26, 7:51 PM CDT, 1 hour 55 minutes before

IAZALL-270135-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
750 PM CDT FRI APR 26 1991

...A TORNADO WATCH REMAINS IN EFFECT FOR MOST OF WESTERN IOWA
   UNTIL MIDNIGHT THIS FRIDAY EVENING.

AT 727 PM CDT...INTENSE THUNDERSTORMS WERE LOCATED OVER EXTREME WEST
CENTRAL IOWA...IN A 10 MILE WIDE AREA...FROM NEAR MAPLETON...30 MILES
SOUTHEAST OF SIOUX CITY...TO JUST NORTH OF COUNCIL BLUFFS.

THESE INTENSE STORMS...WERE PRODUCING BRIEF VERY HEAVY RAIN...
FREQUENT DANGEROUS LIGHTNING...AND COULD ALSO PRODUCE SOME LARGE
HAIL AND STRONG GUSTY WIND.

OVER THE REMAINDER OF ABOUT THE WEST HALF OF IOWA...NUMEROUST SHOWERS
AND STRONG THUNDERSTORMS CONTINUED TO DEVELOP.

THE STORMS WERE MOVING NORTHEAST AT 45 MILES AN HOUR.
PEOPLE IN THE PATH OF THESE NUMEROUS STRONG THUNDERSTORMS
SHOULD REMAIN ALERT FOR RAPIDLY CHANGING CONDITIONS...AND
BE PREPARED TO SEEK SHELTER IMMEDIATELY SHOULD THREATENING
WEATHER APP.ROACH.

JAK/WPM

Special weather statement, Apr 26, 8:05 PM CDT, 1 hour 41 minutes before

IAZALL-270200-

SPECIAL WEATHER STATEMENT AND IOWA WEAHTER UPDATE
NATIONAL WEATHER SERVICE DES MOINES IA
805 PM CDT FRI APR 26 1991

...A TORNADO WATCH REMAINS IN EFFECT FOR MUCH OF THE WEST HALF OF
   IOWA UNTIL 2 AM SATURDAY MORNING...AND FOR EXTREME NORTHWEST
   IOWA UNTIL MIDNIGHT THIS FRIDAY EVENING...

WIDELY SCATTERED INTENSE THUNDERSTORMS CONTINUED OVER WEST CENTRAL
AND SOUTHWEST IOWA.  IN WEST CENTRAL IOWA...THE STRONGEST STORMS WERE
LOCATED IN ABOUT A 20 MILE WIDE AREA...FROM NEAR DENNISON...OR 45
MILES SOUTHWEST OF SIOUX CITY...TO NEAR SAC CITY...OR 45 MILES WEST
OF FORT DODGE.  IN SOUTHWEST IOWA...THE STRONGEST STORMS WERE LOCATED
IN ABOUT A 10 MILE WIDE BAND...CENTERED FROM JUST NORTHEAST OF VALISCA
...60 MILES SOUTHEAST OF COUNCIL BLUFFS...SOUTH TO THE IOWA/MISSOURI
BORDER.

OVER THE REMAINDER OF ABOUT THE WEST HALF OF IOWA...NUMEROUS SHOWERS
AND STRONG THUNDERSTORMS CONTINUED TO DEVELOP.

THESE STORMS WERE MOVING NORTHEAST AT 45 MILES AN HOUR.

PEOPLE IN THE PATH OF THESE NUMEROUS STRONG THUNDERSTORMS
SHOULD REMAIN ALERT FOR RAPIDLY CHANGING CONDITIONS...AND
BE PREPARED TO SEEK SHELTER IMMEDIATELY SHOULD THREATENING
WEATHER APPROACH.

THE OUTLOOK THROUGH 9 CPM IS FOR CONTINUED STRONG THUNDERSTORMS
TO CONTINUED OVER ABOUT THE WEST HALF OF IOWA...WITH A MOSTLY
CLOUDY SKY ELSEWHERE.

JAK/WPM

Special weather statement, Apr 26, 8:49 PM CDT, 57 minutes before

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Special weather statement, Apr 26, 9:03 PM CDT, 43 minutes before

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Special weather statement, Apr 26, 9:15 PM CDT, 31 minutes before

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Special weather statement, Apr 26, 9:41 PM CDT, 5 minutes before

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        The site you requested is temporarily down for maintenance or an unexpected outage.
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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
Apr 26, 7:43 PM CDT	Severe Thunderstorm Warning	DMX	Crawford	32 min
Apr 26, 7:49 PM CDT	Tornado Warning	DMX	Crawford	26 min
Apr 26, 8:19 PM CDT	Tornado Warning	DMX	Sac	56 min
Apr 26, 8:36 PM CDT	Severe Thunderstorm Warning	DMX	Buena Vista	29 min
Apr 26, 8:55 PM CDT	Severe Thunderstorm Warning	DMX	Ringgold	30 min
Apr 26, 9:19 PM CDT	Severe Thunderstorm Warning	DMX	Decatur	35 min
Apr 26, 9:19 PM CDT	Severe Thunderstorm Warning	DMX	Clarke	41 min
Apr 26, 10:59 PM CDT	Severe Thunderstorm Warning	DMX	Lucas, Wayne	31 min
Apr 26, 11:18 PM CDT	Tornado Warning	DMX	Wayne	27 min
Apr 26, 11:23 PM CDT	Tornado Warning	DMX	Lucas	37 min
Apr 27, 12:02 AM CDT	Severe Thunderstorm Warning	DMX	Mahaska, Marion, Monroe	28 min
Apr 27, 1:30 AM CDT	Severe Thunderstorm Warning	DMX	Mahaska	45 min
Apr 27, 2:04 AM CDT	Tornado Warning	DMX	Iowa	41 min
Apr 27, 2:04 AM CDT	Tornado Warning	DMX	Keokuk	15 min

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.