Alert archive / Iowa / Tornado Warnings in 1987
Tornado Warning 6, NWS Des Moines, IA
NWS Des Moines, IA issued this tornado warning at Jul 11, 1987, 11:57 PM CDT for Marshall County, Iowa. It was in force for 28 min.
The area
The counties it named.
The facts
- Issued
- Jul 11, 1987, 11:57 PM CDT (04:57 UTC)
- Expired
- Jul 12, 1987, 12:25 AM CDT
- In force
- 28 min
- Issued by
- NWS Des Moines, IA
- Area
- Whole counties
County Marshall County, IA
The radar
The WSR-88D network and its archive begin in 1991, so there is no radar volume for this alert.
The nearest sounding before it
Omaha, NE (KOAX), launched 00:00Z, 5.0 hours before the alert went out and 291 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
- 3602 m above ground
- 0-6 km bulk shear
- 20 kt
- 0-1 km storm-relative helicity
- 98 m²/s²
- 0-3 km storm-relative helicity
- 145 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
000 TTAA00 KDSM 120458 TORDSM IAC127-120525- BULLETIN - IMMEDIATE BROADCAST REQUESTED/EBS ACTIVATION REQUESTED TORNADO WARNING NATIONAL WEATHER SERVICE DES MOINES IA 1157 PM CDT SAT JUL 11 1987 THE NATIONAL WEATHER SERVICE HAS ISSUED A TORNADO WARNING EFFECTIVE UNTIL 1225 AM CDT FOR PEOPLE IN THE FOLLOWING COUNTY OF CENTRAL IOWA... EASTERN MARSHALL AT 1146 PM CDT A CITIZEN REPORTED A TORNADO ON THE GROUND JUST SOUTH OF MARSHALLTOWN. THIS WAS RELAYED TO US BY THE COUNTY SHERIFF. THIS IS ABOUT 50 MILES NORTHEAST OF DES MOINES. TOWNS AFFECTED ARE MARSHALLTOWN...HAVERHILL...FERGUSON...DUNBAR... AND LE GRAND AS WELL AS THOSE PERSONS IN RURAL AREAS. THE TORNADO WAS MOVING EAST AROUND 25 TO 30 MILES AN HOUR. IF A TORNADO APPROACHES...TAKE COVER IMMEDIATELY. A BASEMENT... INTERIOR HALLWAY...OR A ROOM ON THE LOWEST FLOOR IS THE SAFEST PLACE IN MOST BUILDINGS. IF YOU ARE IN A MOBILE HOME OR AN AUTOMOBILE...LEAVE AT ONCE. TAKE COVER IN A STORM SHELTER...OR LIE IN A NEARBY DITCH OR DEPRESSION. THIS IS A DANGEROUS STORM. TAKE COVER IMMEDIATELY. ADAMS/DOWD
What forecasters said that day
The local office's own words before this tornado 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, Jul 11, 7:47 PM CDT, 4 hours 10 minutes before
SPECIAL WEATHER STATEMENT AND RADAR SUMMARY NATIONAL WEATHER SERVICE DES MOINES IA 740 PM CDT SAT JUL 11 1987 ...A SEVERE THUNDERSTORM WATCH IS IN EFFECT FOR MOST OF WESTERN AND NORTHERN IOWA UNTIL 9PM THIS EVENING... ...A FLASH FLOOD WATCH REMAINS IN EFFECT FOR WEST CENTRAL...SOUTHWEST ...AND SOUTH CENTRAL IOWA TONIGHT... NO SEVERE WEATHER WAS REPORTED BETWEEN 630 PM AND 730 PM. AT 730 PM CDT...VERY STRONG THUNDERSTORMS WERE LOCATED OVER NORTHWEST AND NORTH CENTRAL IOWA. THERE WERE TWO CLUSTERS OF VERY STRONG THUNDERSTORMS...ONE... OVER NORTHWEST IOWA...15 MILES WIDE...FROM JUST SOUTH OF CHEROKEE...TO 15 MILES NORTHEAST OF STORM LAKE...OR FROM 30 MILES EAST NORTHEAST OF SIOUX CITY...TO 75 MILES NORTHEAST OF SIOUX CITY. THE OTHER CLUSTER OF VERY STONG THUNDERSTORMS...10 MILES WIDE...WAS LOCATED FROM 25 MILES EAST SOUTHEAST OF MASON CITY....TO 25 MILES NORTHEAST OF FORT DODGE. THESE VERY STRONG STORMS WERE PRODUCING VERY LARGE AMOUNTS OF RAINFALL ...AND COULD PRODUCE SOME SMALL HAIL AS WELL AS STRONG GUSTY WIND...AND WERE PRODUCING FREQUENT DANGEROUS LIGHTNING. OVER THE REMAINDER OF EXTREME NORTHWEST AND NORTH CENTRAL IOWA... SCATTERED SHOWERS AND THUNDERSTORMS CONTINUED. THE SHOWERS AND STORMS WERE MOVING HEAST AT 30 MILES AN HOUR. MARTIN/MILLER
Special weather statement, Jul 11, 8:46 PM CDT, 3 hours 11 minutes before
SEVERE WEATHER STATEMENT AND RADAR SUMMARY NATIONAL WEATHER SERVICE DES MOINES IA 845 PM CDT SAT JUL 11 1987 ...SEVERE THUNDERSTORM WATCH FOR MUCH OF NORTHERN AND CENTRAL IOWA UNTIL 1 AM... ...FLASH FLOOD WATCH FOR WEST CENTRAL...SOUTHWEST...AND SOUTH CENTRAL IOWA TONIGHT... NO SEVERE WEATHER HAS BEEN REPORTED IN IOWA BETWEEN 740 PM AND 840 PM... AT 840 PM... SHOWERS AND INTENSE THUNDERSTORMS CONTINUED OVER ABOUT THE NORTHERN HALF OF THE STATE...ROUGHLY NORTH OF A DENISON...WATERLOO...DECORAH LINE. THERE WERE 3 CLUSTERS OF INTENSE STORMS. THE FIRST STRETCHED FROM NEAR DECORAH TO NEAR WATERLOO...THE SECOND FROM JUST EAST OF ALGONA TO NEAR FORT DODGE...AND THE THIRD FROM NEAR STORM LAKE TO ONAWA... WHICH IS ABOUT 25 MILES SOUTH OF SIOUX CITY. < THE STORMS IN THESE CLUSTER WILL PRODUCE BRIEF HEAVY RAINS...SMALL PEA TO MARBLE SIZED HAIL...AND WINDS OF UP TO 40 MILES AN HOUR. ALL OF THE SHOWERS AND STORM S IN THE STATE WERE MOVING EAST AT 35 MILES AN HOUR. TRUETT/MILLER
Special weather statement, Jul 11, 9:50 PM CDT, 2 hours 7 minutes before
SPECIAL WEATHER STATEMENT AND RADAR SUMMARY NATIONAL WEATHER SERVICE DES MOINES IA 950 PM CDT SAT JUL 11 1987 ...SEVERE THUNDERSTORM WATCH FOR MUCH OF NORTHERN AND CENTRAL IOWA TIL 1 AM... ...FLASH FLOOD WATCH FOR WEST CENTRAL...SOUTHWEST...AND SOUTH CENTRAL IOWA TONIGHT... ...NO SEVERE WEATHER REPORTED IN IOWA BETWEEN 840 PM AND 940 PM... AT 940 PM...SHOWERS AND INTENSE THUNDERSTORMS CONTINUED OVER ABOUT THE NORTHERN HALF OF IOWA...GENERALLY ALONG AND NORTH OF A DENISON... WATERLOO...DECORAH LINE. THE MOST INTENSE STORMS WERE IN CENTRAL AND WESTERN IOWA...IN A 10 MILE WIDE BAND THAT STRETCHED FROM FORT DODGE..TO NEAR STORM LAKE...TO ONAWA ...ABOUT 25 MILES SOUTH OF SIOUX CITY. BRIEF VERY HEAVY RAINS...SMALL PEA TO MARBLE SIZED HAIL...AND WINDS OF 30 TO 40 MILES AN HOUR CAN BE EXPECTED WITH THESE STORMS. < ANOTHER SMALL CLUSTER OF STORMS WAS OVER NORTH CENTRAL IOWA...FROM NEAR MASON CITY TO HAMPTON...ABOUT 25 MILES SOUTH OF MASON CITY. THESE STORMS MAY ALSO PRODUCE BRIEF HEAVY RAINS AND SMALL HAIL. THE SHOWERS AND STORMS WERE MOVING EAST AT 30 MILES AN HOUR...WHILE THE ENTIRE AREA SAGGED SOUTH AT 5 TO 10 MILES AN HOUR. TRUETT/MILLER
Special weather statement, Jul 11, 10:05 PM CDT, 1 hour 52 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE WATERLOO IA 1000 PM CDT SAT JUL 11 1987 ...SEVERE THUNDERSTORM WATCH UNTIL 1AM FOR PARTS OF NORTHERN IOWA... AT 1000PM CDT NATIONAL WEATHER SERVICE RADAR AT WATERLOO WAS SHOWING A NARROW BAND OF VERY STRONG THUNDERSTORMS IN NORTHEAST IOWA FROM 40 MILES NORTH OF WATERLOO NEAR FLOYD TO 20 MILES WEST OF WATERLOO NEAR PARKERSBURG. THESE STORMS WILL BE IN THE NEW HAMPTON AND WAVERLY AREA BETWEEN 1030 AND 1100 PM CDT. THESE THUNDERSTORMS WILL PRODUCE BRIEF HEAVY RAIN...POSSIBLE SMALL HAIL AND STRONG GUST WINDS AS THEY MOVE NORTHEAST AROUND 25 MILES AN HOUR. IN ADDITION TO THESE VERY STRONG STORMS SHOWERS AND THUNDERSHOWERS WAS OCCURING OVER MUCH OF NORTHEAST AND NORTH CENTRAL IOWA. FRANCISCO FRANCISCO
Special weather statement, Jul 11, 10:08 PM CDT, 1 hour 49 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE WATERLOO IA 1000 PM CDT SAT JUL 11 1987 ...SEVERE THUNDERSTORM WATCH UNTIL 1AM FOR PARTS OF NORTHERN IOWA... AT 1000PM CDT NATIONAL WEATHER SERVICE RADAR AT WATERLOO WAS SHOWING A NARROW BAND OF VERY STRONG THUNDERSTORMS IN NORTHEAST IOWA FROM 40 MILES NORTH OF WATERLOO NEAR FLOYD TO 20 MILES WEST OF WATERLOO NEAR PARKERSBURG. THESE STORMS WILL BE IN THE NEW HAMPTON AND WAVERLY AREA BETWEEN 1030 AND 1100 PM CDT. THESE THUNDERSTORMS WILL PRODUCE BRIEF HEAVY RAIN...POSSIBLE SMALL HAIL AND STRONG GUST WINDS AS THEY MOVE EAST AROUND 25 MILES AN HOUR. IN ADDITION TO THESE VERY STRONG STORMS SHOWERS AND THUNDERSHOWERS WAS OCCURING OVER MUCH OF NORTHEAST AND NORTH CENTRAL IOWA. FRANCISCO
Special weather statement, Jul 11, 10:50 PM CDT, 1 hour 7 minutes before
SPECIAL WEATHER STATEMENT AND RADAR SUMMARY NATIONAL WEATHER SERVICE DES MOINES IA 1040PM CDT SAT JUL 11 1987 ...SEVERE THUNDERSTORM WATCH FOR MUCH OF NORTHERN AND CENTRAL IOWA TIL 1 AM... ...FLASH FLOOD WATCH FOR WEST CENTRAL...SOUTHWEST...AND SOUTH CENTRAL IOWA TONIGHT... ...NO SEVERE WEATHER REPORTED IN IOWA BETWEEN 940 PM AND 1040 PM... AT 1035 PM...SHOWERS AND INTENSE THUNDERSTORMS CONTINUED OVER ABOUT THE NORTHERN HALF OF IOWA...GENERALLY ALONG AND NORTH OF A LINE FROM DUBUQUE TO 40 MILES NORTH OF OMAHA. THE MOST INTENSE STORMS WERE IN WESTERN IOWA...IN A 20 MILE WIDE BAND THAT STRETCHED FROM JUST 30 MILES SOUTH OF SIOUX CITY TO SAC CITY... ABOUT 60 MILES EAST OF SIOUX CITY. BRIEF VERY HEAVY RAINS...SMALL PEA TO MARBLE SIZED HAIL...AND WINDS OF 30 TO 40 MILES AN HOUR CAN BE EXPECTED WITH THESE STORMS. A SECOND CLUSTER OF STORMS WAS OVER NORTH CENTRAL IOWA NEAR FORT DODGE AND AN INTENSE THUNDERSTORM WAS ALSO LOCAATED JUST NORTH OF WATERLOO. THESE STORMS MAY ALSO PRODUCE BRIEF HEAVY RAINS AND SMALL HAIL. THE SHOWERS AND STORMS WERE MOVING EAST AT 30 MILES AN HOUR...WHILE THE ENTIRE AREA SAGGED SOUTH AT 5 TO 10 MILES AN HOUR. SCOTT/MILLER
The office that day
Everything else NWS Des Moines, IA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 11, 7:56 PM CDT | Severe Thunderstorm Warning | DMX | Chickasaw | 64 min |
| Jul 11, 8:54 PM CDT | Severe Thunderstorm Warning | DMX | Buena Vista, Pocahontas | 36 min |
| Jul 11, 11:30 PM CDT | Severe Thunderstorm Warning | DMX | Marshall, Story | 40 min |
| Jul 11, 11:50 PM CDT | Severe Thunderstorm Warning | DMX | Black Hawk, Grundy | 55 min |
| Jul 12, 3:05 AM CDT | Flash Flood Warning | DMX | Ringgold, Taylor, Union | 4 hr |
| Jul 12, 3:05 AM CDT | Flash Flood Warning | DMX | Adair, Adams | 65 min |
| Jul 12, 3:06 AM CDT | Flash Flood Warning | DMX | Dallas, Polk | 4 hr |
| Jul 12, 4:10 AM CDT | Flash Flood Warning | DMX | Adams | 3 hr |
Nearby
Tornado Warnings in Iowa, 1987Every tornado warning in 1987Tornadoes in 1987
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.