Alert archive / Iowa / Severe Thunderstorm Warnings in 1991
Severe Thunderstorm Warning 72, NWS Des Moines, IA
NWS Des Moines, IA issued this severe thunderstorm warning at May 17, 1991, 3:17 PM CDT for Black Hawk County, Iowa. It was in force for 58 min. 1 report came from inside the area while it was in force.
The area
The counties it named, with what was reported inside it.
The facts
- Issued
- May 17, 1991, 3:17 PM CDT (20:17 UTC)
- Expired
- May 17, 1991, 4:15 PM CDT
- In force
- 58 min
- Issued by
- NWS Des Moines, IA
- Area
- Whole counties
County Black Hawk County, IA
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| May 17, 3:25 PM CDT | Hail 3 | Black Hawk, IA |
NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in. Storm Data before 1996 records only tornadoes, thunderstorm wind and hail.
The nearest sounding before it
Minneapolis, MN (KSTC), launched 12:00Z, 8.3 hours before the alert went out and 284 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- NaN m above ground
- 0-6 km bulk shear
- 14 kt
- 0-1 km storm-relative helicity
- -30 m²/s²
- 0-3 km storm-relative helicity
- 49 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, May 17, 2:45 PM CDT, 32 minutes before
IAZ002-003-007-172130- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE WATERLOO IA 245 PM CDT FRI MAY 17 1991 ...TORNADO WATCH FOR MUCH OF EASTERN IOWA UNTIL 900 PM... AT 230 PM CDT VERY STRONG THUNDERSTORMS HAVE DEVELOPED RAPIDLY SINCE 200 PM IN PARTS OF NORTHEAST IOWA. THESE STORMS WERE IN 15 MILE WIDE AREA FROM 15 MILES SOUTH OF WATERLOO NEAR HUDSON...TO 40 MILES NORTHWEST OF WATERLOO NEAR HAMPTON. THESE STROMS MAY PRODUCE HEAVY RAIN...LARGE HAIL...STRONG WINDS AND FREQUENT DANGEROUS LIGHTNING. THESE STORMS WILL BE MOVING INTO THE WATERLOO/CEDAR FALLS... PARKERSBURG AND DUMNONT AREA BY 300 PM. A LARGER AREA AREA OF SHOWERS AND SCATTERED THUNDERSTORMS WAS SOUTH OF A LINE FROM THE MINNESOTA BORDER NORTHWEST OF MASON CITY NEAR BUFFALO CENTER...TO 15 MILES SOUTH OF CEDAR RAPIDS. THIS AREA OF SHOWERS AND THUNDERSTORMS WERE MOVING TO THE NORTH AT 15 MILES AN HOUR. MG
Special weather statement, May 17, 2:49 PM CDT, 28 minutes before
IAZ002-003-007-172130- SPECIAL WEATHER STATEMENT...CORRECTION LAST PARAGRAPH NATIONAL WEATHER SERVICE WATERLOO IA 245 PM CDT FRI MAY 17 1991 ...TORNADO WATCH FOR MUCH OF EASTERN IOWA UNTIL 900 PM... AT 230 PM CDT VERY STRONG THUNDERSTORMS HAVE DEVELOPED RAPIDLY SINCE 200 PM IN PARTS OF NORTHEAST IOWA. THESE STORMS WERE IN 15 MILE WIDE AREA FROM 15 MILES SOUTH OF WATERLOO NEAR HUDSON...TO 40 MILES NORTHWEST OF WATERLOO NEAR HAMPTON. THESE STROMS MAY PRODUCE HEAVY RAIN...LARGE HAIL...STRONG WINDS AND FREQUENT DANGEROUS LIGHTNING. THESE STORMS WILL BE MOVING INTO THE WATERLOO/CEDAR FALLS... PARKERSBURG AND DUMNONT AREA BY 300 PM. A LARGER AREA OF SHOWERS AND SCATTERED THUNDERSTORMS WAS SOUTH OF A LINE FROM THE MINNESOTA BORDER NORTHWEST OF MASON CITY NEAR BUFFALO CENTER...TO 15 MILES SOUTH OF CEDAR RAPIDS. THIS AREA OF SHOWERS AND THUNDERSTORMS WAS MOVING TO THE NORTH AT 15 MILES AN HOUR. MG
Special weather statement, May 17, 2:50 PM CDT, 27 minutes before
IAZALL-172030- SPECIAL WEATHER STATEMENT AND RADAR SUMMARY NATIONAL WEATHER SERVICE DES MOINES IA 245 PM CDT FRI MAY 17 1991 ...A TORNADO WATCH REMAINS IN EFFECT FOR MUCH OF WESTERN...CENTRAL... AND EASTERN IOWA...UNTIL 9PM THIS FRIDAY EVENING... ...GOLF BALL SIZE HAIL WAS REPORTED AT WEBSTER CITY AT AROUND 215 PM ...WEBSTER CITY IS ABOUT 50 MILES SOUTHWEST OF MASON CITY. AT 235 PM CDT...INTENSE THUNDERSTORMS WERE LOCATED OVER NORTH CENTRAL AND WEST CENTRAL IOWA. THE STRONGEST STORMS WERE LOCATED NEAR CLARION... OR 40 MILES SOUTHWEST OF MASON CITY...AND JUST SOUTHWEST OF COON RAPIDS ...OR 50 MILES NORTHWEST OF DES MOINES. THESE STORMS HAVE PRODUCED EXTREMELY HEAVY RAIN...FREQUENT DANGEROUS LIGHTNING...GUSTY WIND...AND GOLFBALL SIZE HAIL. OVER THE REMAINDER OF NORTHERN AND EASTERN IOWA...SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE TO DEVELOP. THE SHOWERS AND STORMS WERE MOVING NORTH AT AROUND 15 MILES AN HOUR. SHOULD THREATENING WEATHER APPROACH...BE PREPARED TO SEEK SHELTER IMMEDIATELY. WPM/JAK
The office that day
Everything else NWS Des Moines, IA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 17, 1:54 PM CDT | Severe Thunderstorm Warning | DMX | Wright | 36 min |
| May 17, 2:05 PM CDT | Tornado Warning | DMX | Hamilton, Wright | 25 min |
| May 17, 2:35 PM CDT | Severe Thunderstorm Warning | DMX | Wright | 40 min |
| May 17, 3:01 PM CDT | Severe Thunderstorm Warning | DMX | Greene | 44 min |
| May 17, 3:53 PM CDT | Tornado Warning | DMX | Johnson | 37 min |
| May 17, 4:12 PM CDT | Tornado Warning | DMX | Hamilton, Webster | 33 min |
| May 17, 4:16 PM CDT | Severe Thunderstorm Warning | DMX | Appanoose, Davis | 44 min |
| May 17, 4:22 PM CDT | Severe Thunderstorm Warning | DMX | Floyd | 38 min |
| May 17, 4:22 PM CDT | Severe Thunderstorm Warning | DMX | Butler, Grundy | 68 min |
| May 17, 4:55 PM CDT | Tornado Warning | DMX | Wright | 50 min |
| May 17, 5:14 PM CDT | Severe Thunderstorm Warning | DMX | Benton, Iowa | 46 min |
| May 17, 5:27 PM CDT | Severe Thunderstorm Warning | DMX | Van Buren | 48 min |
| May 17, 5:36 PM CDT | Severe Thunderstorm Warning | DMX | Iowa, Johnson, Linn | 69 min |
| May 17, 5:45 PM CDT | Flash Flood Warning | DMX | Hamilton, Hardin, Humboldt, Webster, Wright | 4 hr |
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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive.