Alert archive / Illinois / Severe Thunderstorm Warnings in 1987
Severe Thunderstorm Warning 35, NWS St. Louis, MO
NWS St. Louis, MO issued this severe thunderstorm warning at Jul 6, 1987, 11:20 AM CDT for Saint Clair County, Illinois. It was in force for 55 min. 5 reports 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
- Jul 6, 1987, 11:20 AM CDT (16:20 UTC)
- Expired
- Jul 6, 1987, 12:15 PM CDT
- In force
- 55 min
- Issued by
- NWS St. Louis, MO
- Area
- Whole counties
County Saint Clair County, IL
The radar
The WSR-88D network and its archive begin in 1991, so there is no radar volume for this alert.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Jul 6, 11:35 AM CDT | Hail 0.75 | St. Clair, IL | |
| Jul 6, 11:40 AM CDT | Hail 1.75 | St. Clair, IL | |
| Jul 6, 11:50 AM CDT | Hail 3.5 | St. Clair, IL | |
| Jul 6, 11:56 AM CDT | Hail 1 | St. Clair, IL | |
| Jul 6, 12:05 PM CDT | Hail 3.5 | St. Clair, IL |
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
Salem-Leckrone, IL (KSLO), launched 12:00Z, 4.3 hours before the alert went out and 92 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
- 2811 J/kg
- Mixed-layer CIN
- -34 J/kg
- Mixed-layer LCL
- 724 m above ground
- 0-6 km bulk shear
- 38 kt
- 0-1 km storm-relative helicity
- 151 m²/s²
- 0-3 km storm-relative helicity
- 143 m²/s²
- Significant tornado parameter
- 1.7
- Supercell composite
- 8.8
The text
As transmitted, in the capitals the NWS used until 2016.
000 TTAA00 KSTL 061620 SVRSTL ILC163-061715- BULLETIN - IMMEDIATE BROADCAST REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE ST LOUIS MO 1120 AM CDT MON JUL 6 1987 THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL 1215 PM CDT FOR THE FOLLOWING COUNTY OF SOUTHWEST ILLINOIS... ST. CLAIR AT 1117 AM A SEVERE THUNDERSTORM WAS OVER SOUTH ST LOUIS COUNTY MOVING EAST AT 25 MPH. THE STORM PRODUCED LARGE HAIL IN PARTS OF SOUTH ST. LOUIS COUNTY AND NEAR THE SOUTHERN LIMITS OF ST LOUIS CITY BETWEEN 11 AND 1115 AM. PROTECT YOURSELF FROM DAMAGING WINDS...LARGE HAIL AND LIGHTNING BY STAYING IN A BUILDING...AWAY FROM WINDOWS. DO NOT USE THE TELEPHONE OR ELECTRICAL APPLIANCES...EXCEPT IN EMERGENCIES. MCCARTHY
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, Jul 6, 10:12 AM CDT, 1 hour 8 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE ST LOUIS MO 1010 AM CDT MON JUL 6 1987 ...ONE VERY STRONG THUNDERSTORM WEST OF ST. LOUIS... AT 1010 AM ONE LARGE...VERY STRONG THUNDERSTORM WAS 40 MILES WEST OF ST LOUIS...BETWEEN WASHINGTON AND WENTZVILLE MISSOURI...MOVING EAST AT 25 MPH. THIS STORM WILL PRODUCE EXTREMELY HEAVY RAIN...STRONG WINDS...FREQUENT LIGHTNING AND POSSIBLY HAIL AS IT MOVES THROUGH ST. CHARLES COUNTY...THE NORTHEASKT TIP OF FRANKLIN COUNTY AND INTO WEST ST. LOUIS COUNTY BY 11 AM. MCCARTHY
Special weather statement, Jul 6, 10:30 AM CDT, 50 minutes before
SPECIAL WEATHER STATEMENT AND RADAR SUMMARY NATIONAL WEATHER SERVICE ST LOUIS MO 1030 AM CDT MON JUL 6 1987 ...ONE VERY STRONG THUNDERSTORM WEST OF ST. LOUIS... AT 1025 AM...ONE VERY STRONG THUNDERSTORM WAS 35 MILES WEST OF ST LOUIS...JUST SOUTH OF WENTZVILLE MISSOURI...MOVING EAST AT 25 MILES AN HOUR. THIS STORM WILL PRODUCE EXTREMELY HEAVY RAIN...STRONG WINDS...FREQUENT LIGHTNING AND POSSIBLY HAIL AS IT MOVES THROUGH ST. CHARLES COUNT_Y...THE NORTHEAST TIP OF FRANKLIN COUNTY AND INTO WEST ST. LOUIS COUNTY BY 11 AM. HUTSELL
The office that day
Everything else NWS St. Louis, MO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 5, 8:09 PM CDT | Severe Thunderstorm Warning | LSX | Calhoun, Jersey | 36 min |
| Jul 6, 12:00 PM CDT | Severe Thunderstorm Warning | LSX | Clinton, Saint Clair, Washington | 60 min |
| Jul 6, 1:05 PM CDT | Severe Thunderstorm Warning | LSX | Jefferson, Marion, Washington | 40 min |
| Jul 6, 3:10 PM CDT | Severe Thunderstorm Warning | LSX | Calhoun, Pike | 50 min |
| Jul 6, 3:24 PM CDT | Severe Thunderstorm Warning | LSX | Greene | 39 min |
| Jul 6, 4:24 PM CDT | Severe Thunderstorm Warning | LSX | Calhoun, Jersey, Madison | 51 min |
| Jul 6, 4:55 PM CDT | Severe Thunderstorm Warning | LSX | Saint Clair | 35 min |
| Jul 6, 5:26 PM CDT | Severe Thunderstorm Warning | LSX | Fayette | 64 min |
| Jul 6, 5:52 PM CDT | Severe Thunderstorm Warning | LSX | Effingham | 53 min |
Nearby
Severe Thunderstorm Warnings in Illinois, 1987Every severe thunderstorm warning 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive.