Alert archive / Iowa / Severe Thunderstorm Warnings in 1991
Severe Thunderstorm Warning 91, NWS Sioux Falls, SD
NWS Sioux Falls, SD issued this severe thunderstorm warning at Aug 7, 1991, 5:08 PM CDT for Sioux County, Iowa. It was in force for 52 min.
The area
The counties it named.
The facts
- Issued
- Aug 7, 1991, 5:08 PM CDT (22:08 UTC)
- Expired
- Aug 7, 1991, 6:00 PM CDT
- In force
- 52 min
- Issued by
- NWS Sioux Falls, SD
- Area
- Whole counties
County Sioux County, IA
The nearest sounding before it
Omaha, NE (KOVN), launched 12:00Z, 10.1 hours before the alert went out and 197 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.
- Mixed-layer CAPE
- 1226 J/kg
- Mixed-layer CIN
- -202 J/kg
- Mixed-layer LCL
- 1659 m above ground
- 0-6 km bulk shear
- 22 kt
- 0-1 km storm-relative helicity
- 114 m²/s²
- 0-3 km storm-relative helicity
- 67 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
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, Aug 7, 4:10 PM CDT, 58 minutes before
SDZ018-019-020-072200- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE SIOUX FALLS SD 410 PM CDT WED AUG 7 1991 ...A SEVERE THUNDERSTORM WATCH IS IN EFFECT FOR PORTIONS OF SOUTHEAST SOUTH DAKOTA UNTIL 1000 PM CDT... SHOWERS AND THUNDERSTORMS DEVELOPED ACROSS SOUTHEAST SOUTH DAKOTA THIS AFTERNOON. THE STORMS EXTENDED FROM CHARLES MIX COUNTY TO MOODY COUNTY AND WERE MOVING NORTHEAST AT 10 MILES AN HOUR. THUNDERSTORMS WILL CONTINUE OVER SOUTHEAST SOUTH DAKOTA THIS EVENING... AND SOME STORMS MAY BE SEVERE. IF A THUNDERSTORM APPROACHES YOUR AREA ...SEEK SHELTER INSIDE A REINFORCED BUILDING IMMEDIATELY. ALSO REMEMBER THAT LIGHTNING IS EXTREMELY DANGEROUS. MENTZER
Special weather statement, Aug 7, 4:36 PM CDT, 32 minutes before
IAZ001-004-005-072230- SPECIAL WEATHER STATEMENT AND WEATHER UPDATE NATIONAL WEATHER SERVICE SIOUX CITY IA 430 PM CDT WED AUG 7 1991 ...SEVERE THUNDERSTORM WATCH FOR MUCH OF THE SIOUXLAND AREA TIL 10 PM... AT 425 PM...SCATTERED STRONG THUNDERSTORMS WERE LOCATED BETWEEN ELK POINT SOUTH DAKOTA...20 MILES NORTHWEST OF SIOUX CITY AND DIXON NEBRASKA ...30 MILES SOUTHWEST OF SIOUX CITY. AN AREA OF SHOWERS WAS BETWEEN AKRON AND ORANGE CITY IOWA OR 25 MILES NORTHWEST TO 40 MILES NORTHEAST OF SIOUX CITY. THE STORMS AND SHOWERS WERE MOVING NORTHEAST AT 35 MILES AN HOUR. THE STRONGER STORMS WERE LIKELY PRODUCING BRIEF HEAVY AND SOME SMALL HAIL. THE STORMS WILL MOVE INTO ELK POINT SOUTH DAKOTA AROUND 5 PM. PEOPLE IN EXTREME SOUTHEAST SOUTH DAKOTA AND FAR NORTHEAST NEBRASKA SHOULD BE ALERT FOR RAPIDLY CHANGING WEATHER CONDITIONS...AND BE PREPARED TO MOVE TO A PLACE OF SAFETY. S. QUINN
Special weather statement, Aug 7, 4:41 PM CDT, 27 minutes before
IAZ001-072230- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE SIOUX FALLS SD 440 PM CDT WED AUG 7 1991 ...A SEVERE THUNDERSTORM WATCH IS IN EFFECT FOR PORTIONS OF SOUTHEAST SOUTH DAKOTA AND NORTHWEST IOWA UNTIL 1000 PM CDT... AT 435 PM CDT A STRONG THUNDERSTORM HAD DEVELOPED OVER NORTHWEST IOWA... 35 MILES NORTH OF SIOUX CITY OR JUST EAST OF HAWARDEN. THIS STORM SHOWED LITTLE MOVEMENT. PERSONS NEAR THE STORM SHOULD BE PREPARED FOR THIS TIHREATENING WEATHER. VERY HEAVY RAINS...GUSTY WINDS...HAIL...AND FREQUENT LIGHTNING CAN BE EXPECTED WITH THIS STORM. GEELHART
The office that day
Everything else NWS Sioux Falls, SD issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 7, 5:02 PM CDT | Severe Thunderstorm Warning | FSD | Plymouth | 28 min |
| Aug 7, 5:38 PM CDT | Severe Thunderstorm Warning | FSD | Plymouth | 67 min |
| Aug 7, 6:09 PM CDT | Tornado Warning | FSD | Cherokee, Plymouth | 36 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.