Alert archive / Iowa / Severe Thunderstorm Warnings in 1991
Severe Thunderstorm Warning 78, NWS Des Moines, IA
NWS Des Moines, IA issued this severe thunderstorm warning at May 17, 1991, 5:36 PM CDT for Iowa County, Johnson County, Linn County, Iowa. It was in force for 69 min.
The area
The counties it named.
The facts
- Issued
- May 17, 1991, 5:36 PM CDT (22:36 UTC)
- Expired
- May 17, 1991, 6:45 PM CDT
- In force
- 69 min
- Issued by
- NWS Des Moines, IA
- Area
- Whole counties
Counties Iowa County, IA, Johnson County, IA, Linn County, IA
The nearest sounding before it
Minneapolis, MN (KSTC), launched 12:00Z, 10.6 hours before the alert went out and 369 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, 2:49 PM CDT, 2 hours 47 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, 2 hours 46 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
Special weather statement, May 17, 3:20 PM CDT, 2 hours 16 minutes before
IAZALL-172030- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DES MOINES IA 315 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... SCATTERED INTENSE THUNDERSTORMS CONTINUE TO DEVELOP IN ABOUT A 20 MILE WIDE AREA...FROM EAST CENTRAL INTO NORTHEAST AND NORTH CENTRAL IOWA. THESE INTENSE STORMS WERE LOCATED FROM NEAR CONESVILLE...45 MILES WEST OF DAVENPORT...TO WATERLOO...TO 70 MILES SOUTHWEST OF MASON CITY...NEAR GILMORE CITY. ANOTHER SMALL AREA OF INTENSE STORMS WAS LOCATED BETWEEN OGDEN...JEFFERSON...AND COON RAPIDS...OR 45 MILES THROUGH 65 MILES NORTHWEST OF DES MOINES. THESE INTENSE STORMS...ALONG WITH EXTREMELY LARGE AMOUNTS OF RAIN... HAVE PRODUCED 1 INCH OR LARGER HAIL...STRONG GUSTY WIND...FREQUENT DANGEROUS LIGHTNING. THESE STORMS WERE MOVING NORTH A 15 MILES AN HOUR. SHOULD THREATENING WEATHER APPROACH...BE PREPARERD TO SEEK SHELTER IMMEDIATELY. WPM/JAK
Special weather statement, May 17, 4:03 PM CDT, 1 hour 33 minutes before
IAZALL-172130- SPECIAL WEATHER STATEMENT AND RADAR SUMMARY NATIONAL WEATHER SERVICE DES MOINES IA 355 PM CDT FRI MAY 17 1991 ...A TORNADO WATCH REMAINS IN EFFECT FOR MUCH OF IOWA UNTIL 9PM CDT THIS FRIDAY EVENING... AT 335 PM CDT...NUMEROUS INTENSE THUNDERSTORMS CONTINUED...FROM EXTREME EAST CENTRAL...INTO NORTHEAST...AND NORTH CENTRAL IOWA. MOST OF THESE INTENSE STORMS WERE LOCATED IN ABOUT A 25 MILE WIDE AREA FROM JUST NORTHWEST OF DAVENPORT..TO NEAR IOWA CITY....CEDAR RAPIDS... WATERLOO...TO 35 MILES SOUTH OF MASON CITY...TO NEAR GILMORE CITY...OR 70 MILES SOUTHWEST OF MASON CITY. ANOTHER SMALL AREA OF INTENSE STORMS WAS LOCATED FROM 45 MILES NORTHWEST OF DES MOINES TO 55 MILES NORTHWEST OF DES MOINES...OR FROM JUST NORTHWEST OF BOONE TO JUST NORTHEAST OF COON RAPIDS. THESE STORMS HAVE BEEN PRODUCING VERY LARGE AMOUNTS OF RAIN...LARGE HAIL...SOME THE SIZE OF BASEBALLS...FREQUENT DANGEROUS LIGHTNING... AND STRONG GUSTY WIND. THE STORMS WERE MOVING NORTHEAST AT 10 TO 15 MILES AN HOUR. SHOULD THREATENING WEATHER APPROACH...BE PREPARED TO SEEK SHELTER IMMEDIATELY. WPM/JAK
Special weather statement, May 17, 4:54 PM CDT, 42 minutes before
IAZALL-172230- SPECIAL WEATHER STATEMENT AND RADAR SUMMARY NATIONAL WEATHER SERVICE DES MOINES IA 452 PM CDT FRI MAY 17 1991 ...A TORNADO WATCH REMAINS IN EFFECT FOR MUCH OF IOWA UNTIL 9PM CDT THIS FRIDAY EVENING... AT 432 PM CDT...SCATTERED SHOWERS AND ISOLATED INTENSE THUNDERSTORMS WERE LOCATED OVER MUCH OF IOWA. THE STRONGEST STORMS WERE LOCATED FROM 25 MILES SOUTHWEST TO 15 MILES SOUTHEAST OF FORT DODGE...20 MILES NORTHEAST OF WATERLOO...40 MILES SOUTHWEST OF CEDAR RAPIDS...AND 30 MILES SOUTH OF OTTUMWA. THESE STORMS HAVE BEEN PRODUCING VERY LARGE AMOUNTS OF RAIN...LARGE HAIL...AN INCH AND LARGER IN DIAMETER...FREQUENT DEADLY LIGHTNING AND GUSTY WINDS. THE SHOWERS AND STORMS WERE MOVING NORTHEAST AT 35 MILES AN HOUR. SHOULD THREATENING WEATHER APPROACH...BE PREPARED TO TAKE SHELTER IMMEDIATELY. WS/JAK
Special weather statement, May 17, 5:17 PM CDT, 19 minutes before
IAZALL-172315- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DES MOINES IA 515 PM CDT FRI MAY 17 1991 ...A TORNADO WATCH REMAINS IN EFFECT FOR MUCH OF IOWA UNTIL 9PM CDT THIS FRIDAY EVENING... AT 510 PM CDT...SCATTERED INTENSE THUNDERSTORMS CONTINUED OVER THE NORTHEAST TWO THIRDS OF IOWA. THESE STRONG STORMS WERE LOCATED FROM 25 MILES WEST OF DES MOINES AT REDFIELD...TO 30 MILES SOUTHWEST OF FORT DODGE...TO 35 MILES WEST OF WATERLOO BETWEEN IOWA FALLS AND ELDORA. OTHER STRONG STORMS WERE 30 MILES WEST TO 15 MILES SOUTHWEST OF CEDAR RAPIDS...AND 15 TO 35 MILES SOUTHEAST OF OTTUMWA. THESE STORMS HAVE BEEN PRODUCING LARGE AMOUNTS OF RAIN...LARGE HAIL...FREQUENT DEADLY LIGHTNING AN D STRONG GUSTY WINDS. THE SHOWERS AND STORMS WERE MOVING NORTHEAST AT 35 MILES AN HOUR. SHOULD THREATENING WEATHER APPROACH...BE PREPARED TO SEEK SHELTER IMMEDIATELY. WS/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, 3:17 PM CDT | Severe Thunderstorm Warning | DMX | Black Hawk | 58 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, 5:45 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; the sounding from the Mesonet's radiosonde archive.