Alert archive / Iowa / Severe Thunderstorm Warnings in 1991

Severe Thunderstorm Warning 32, NWS Des Moines, IA

April 27, 1991Mahaska County, Marion County, Monroe County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Apr 27, 1991, 12:02 AM CDT for Mahaska County, Marion County, Monroe County, Iowa. It was in force for 28 min.

The area

The counties it named.

The facts

Issued
Apr 27, 1991, 12:02 AM CDT (05:02 UTC)
Expired
Apr 27, 1991, 12:30 AM CDT
In force
28 min
Issued by
NWS Des Moines, IA
Area
Whole counties

Counties Mahaska County, IA, Marion County, IA, Monroe County, IA

The nearest sounding before it

Topeka, KS (KTOP), launched 00:00Z, 5.0 hours before the alert went out and 342 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, Topeka, KS at 00:00Z on 1991-04-27Temperature 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, Topeka, KS at 00:00Z on 1991-04-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 409 square meters per square second.1939587897117Sfc1 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
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, 10:43 PM CDT, 1 hour 19 minutes before
IAZALL-270435-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
1040 PM CDT FRI APR 26 1991

...A TORNADO WATCH REMAINS IN EFFECT FOR MUCH OF SOUTHWEST IOWA
   UNTIL 2 AM SATURDAY MORNING...
...A TORNADO WATCH REMAINS IN EFFECT UNTIL 1 AM FOR PORTIONS OF
   NORTH CENTRAL IOWA...
...A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 4 AM SATURDAY
   FOR A LARGE PORTION OF SOUTHERN AND EASTERN IOWA...

AT 1028 PM CDT...SHOWERS AND THUNDERSTORMS CONTINUED OVER MUCH OF
THE WEST HALF OF IOWA.

WITHIN THIS LARGE AREA OF SHOWERS AND STORMS...SCATTERED INTENSE STORMS
CONTINUED OVER CENTRAL IOWA...AND WERE LOCATED IN A NARROW BAND...10
MILES WIDE...FROM NEAR STORY CITY...45 MILES NORTH OF DES MOINES...TO 15
MILES EAST OF DES MOINES.  OVER SOUTHWEST IOWA...ANOTHER 10 MILE WIDE
BAND...FROM NEAR ATLANTIC TO THE IOWA/MISSOURI BORDER SOUTH OF CLARINDA
...OR FROM 45 MILES EAST...TO 70 MILES SOUTHEAST OF COUNCIL
BLUFFS.

THESE INTENSE STORMS HAVE BEEN PRODUCING VERY LARGE AMOUNTS OF
RAINFALL...FREQUENT DANGEROUS LIGHTNING...AND COULD PRODUCE
HAIL AND BRIEF STRONG GUSTY WIND.

THE SHOWERS AND STORMS WERE MOVING NORTHEAST AT 45 MILES AN HOUR.

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

JAK/WPM
Special weather statement, Apr 26, 10:50 PM CDT, 1 hour 12 minutes before
IAZ006-007-270445-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
1050 PM CDT FRI APR 26 1991

AT 1045 PM...A VERY INTENSE THUNDERSTORM WAS NEAR IOWA FALLS WHICH IS
30 MILES WEST OF WATERLOO IN NORTH CENTRAL IOWA. THIS STORM IS LIKELY
TO PRODUCE WINDS IN EXCESS OF 50 MILES AN HOUR AND SMALL HAIL WITH ITS
PASSAGE. TH

THE STORM WAS MOVING NORTH NORTHEAST AT 45 MILES AN HOUR.

CITIES IN THE DIRECT PATH OF THIS STORM ARE IOWA &FALLS...ACKLEY AND
POPEJOY.

REMEMBER...A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 400 AM.

MCQUIRTER
Special weather statement, Apr 26, 11:14 PM CDT, 48 minutes before
IAZALL-270500-

SPECIAL WEATHER STATEMENT AND IOWA WEATHER UPDATE
NATIONAL WEATHER SERVICE DES MOINES IA
1115 PM CDT FRI APR 26 1991

...A TORNADO WATCH REMAINS IN EFFECT FOR MUCH OF SOUTHWEST IOWA
   UNTIL 2 AM SATURDAY MORNING...
...A TORNADO WATCH REMAINS IN EFFECT UNTIL 1 AM FOR PORTIONS OF
   NORTH CENTRAL IOWA...
...A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 4 AM SATURDAY
   FOR A LARGE PORTION OF SOUTHERN AND EASTERN IOWA...

AT 11 PM CDT...SHOWERS AND THUNDERSTORMS CONTINUED OVER MUCH OF
THE WEST TWO THIRDS OF IOWA...GENERALLY WEST OF A LINE FROM WATERLOO
TO OTTUMWA.

WITHIN THIS LARGE AREA OF SHOWERS AND STORMS...SCATTERED INTENSE STORMS
CONTINUED OVER CENTRAL AND NORTH CENTRAL IOWA...IN A 10 MILE WIDE BAND
EXTENDING FROM ACKLEY...35 MILES WEST OF WATERLOO...TO 25 MILES EAST OF
DES MOINES NEAR MONROE.  OTHER INTENSE STORMS WERE LOCATED FROM 50 MILES
SOUTHWEST OF DES MOINES NEAR CRESTON TO 45 MILES NORTHWEST OF
DES MOINES NEAR COON RAPIDS...AND FROM 20 MILES WEST TO 40 MILES
NORTHEAST OF LAMONI.

THESE INTENSE STORMS HAVE BEEN PRODUCING VERY LARGE AMOUNTS OF
RAINFALL...FREQUENT DANGEROUS LIGHTNING...AND COULD PRODUCE
HAIL AND BRIEF STRONG GUSTY WIND.

THE SHOWERS AND STORMS WERE MOVING NORTHEAST AT 45 MILES AN HOUR.

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

WPM/JAK
Special weather statement, Apr 26, 11:14 PM CDT, 48 minutes before
IAZ002-003-006-007-270600-

SPECIAL WEATHER STATEMENT AND WEATHER UPDATE FOR NORTHEAST IOWA
NATIONAL WEATHER SERVICE WATERLOO IA
1110 PM CDT FRI APR 26 1991

...A TORNADO WATCH IS IN EFFECT UNTIL 2AM FOR PARTS OF NORTH CENTRAL
IOWA...A SEVERE THUNDERSTORM WATCH FOR PARTS OF NORTHEAST IOWA
UNTIL 4AM CDT...

AT 1110 PM CDT AN AREA OF VERY STRONG THUNDERSTORMS 15 MILES WIDE
EXTENDED FROM 10 MILES EAST OF MASON CITY TO ABOUT 30 MILES SOUTHWEST
WATERLOO SOUTH OF GRUNDY CENTER.  THESE THUDERSTORMS WERE MOVING
RAPIDLY TO THE NORTH AT ABOUT 45 MILES AN HOUR AND HAVE PRODUCED
BRIEF HEAVY RAIN...WINDS TO AROUND 40 MILES AN HOUR AND FREQUENT
LIGHTNING.

THIS AREA OF THUNDERSTORMS WILL BE MOVING INTO ATHE PARKERSBURG...
DUMONT...GRUNDY CENTER...ALLISON AND CLARKSVILLE AREAS BY MIDNIGHT
THESE TOWNS ARE JUST WEST OF WATERLOO.  THESE STORMS ARE POTENTIALLY
DANGEROUS. TAKE COVER IMMEDIATELY IF SEVERE WEATHER OCCURS.
Special weather statement, Apr 26, 11:42 PM CDT, 20 minutes before
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Special weather statement, Apr 26, 11:44 PM CDT, 18 minutes before
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    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
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The office that day

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

IssuedProductOfficeCountiesLasted
Apr 26, 7:43 PM CDTSevere Thunderstorm WarningDMXCrawford32 min
Apr 26, 7:49 PM CDTTornado WarningDMXCrawford26 min
Apr 26, 8:19 PM CDTTornado WarningDMXSac56 min
Apr 26, 8:36 PM CDTSevere Thunderstorm WarningDMXBuena Vista29 min
Apr 26, 8:55 PM CDTSevere Thunderstorm WarningDMXRinggold30 min
Apr 26, 9:19 PM CDTSevere Thunderstorm WarningDMXDecatur35 min
Apr 26, 9:19 PM CDTSevere Thunderstorm WarningDMXClarke41 min
Apr 26, 9:46 PM CDTSevere Thunderstorm WarningDMXPolk, Warren44 min
Apr 26, 10:59 PM CDTSevere Thunderstorm WarningDMXLucas, Wayne31 min
Apr 26, 11:18 PM CDTTornado WarningDMXWayne27 min
Apr 26, 11:23 PM CDTTornado WarningDMXLucas37 min
Apr 27, 1:30 AM CDTSevere Thunderstorm WarningDMXMahaska45 min
Apr 27, 2:04 AM CDTTornado WarningDMXIowa41 min
Apr 27, 2:04 AM CDTTornado WarningDMXKeokuk15 min

Nearby

Severe Thunderstorm Warnings in Iowa, 1991Every 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.