Alert archive / Illinois / Severe Thunderstorm Warnings in 1997
Severe Thunderstorm Warning 30, NWS Chicago, IL
NWS Chicago, IL issued this severe thunderstorm warning at Apr 30, 1997, 3:12 PM CDT for DeKalb County, Illinois. It was in force for 48 min. No storm report in the archive falls inside the area while it was in force.
The area
The counties it named.
The facts
- Issued
- Apr 30, 1997, 3:12 PM CDT (20:12 UTC)
- Expired
- Apr 30, 1997, 4:00 PM CDT
- In force
- 48 min
- Issued by
- NWS Chicago, IL
- Area
- Whole counties
County DeKalb County, IL
The radar
The Chicago radar (KLOT), 65 km from the middle of the area, began a volume at 20:12 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
The watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Apr 30, 12:30 PM CDT | Tornado Watch | SPC | 7 hr |
The nearest sounding before it
Davenport, (KDVN), launched 12:00Z, 8.2 hours before the alert went out and 147 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
- 1366 m above ground
- 0-6 km bulk shear
- 54 kt
- 0-1 km storm-relative helicity
- 75 m²/s²
- 0-3 km storm-relative helicity
- 180 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, Apr 30, 11:00 AM CDT, 4 hours 12 minutes before
ILZ003>006-008-010>014-019>023-032>033-039-INZ001>005-010>016-019>020- 011100- HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE CHICAGO IL 1100 AM CDT WED APR 30 1997 FOR NORTH CENTRAL AND NORTHEAST ILLINOIS AND NORTHWEST AND NORTH CENTRAL INDIANA ...SEVERE THUNDERSTORMS POSSIBLE THIS AFTERNOON AND EVENING... THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS NORTH CENTRAL AND NORTHEAST ILLINOIS AS WELL AS NORTHERN INDIANA. AT 11 AM CDT THE CENTER OF A STRONG LOW PRESSURE AREA WAS LOCATED OVER NORTH CENTRAL MISSOURI. THE LOW IS EXPECTED TO MOVE NORTHEAST TO NEAR ROCKFORD BY EARLY THIS EVENING...THEN TO NEAR MUSKEGON MICHIGAN BY AROUND MIDNIGHT. THIS MEANS THAT MILD AND MORE MOIST AIR OVER THE MID MISSISSIPPI VALLEY WILL BE DRAWN INTO THE MODERATE RISK AREA PROVIDING THE INGREDIENTS FOR THUNDERSTORM DEVELOPMENT. IN ADDITION...WIND VELOCITIES FROM THE GROUND TO MID LEVELS OF THE ATMOSPHERE WILL BE FAVORABLE FOR SOME OF THESE STORMS TO BECOME TORNADIC. PERSONS ACROSS NORTHERN ILLINOIS AND NORTHERN INDIANA SHOULD STAY ALERT FOR RAPID THUNDERSTORM DEVELOPMENT LATER THIS AFTERNOON AND LISTEN FOR LATER STATEMENTS REGARDING THIS POTENTIALLY SEVERE WEATHER SITUATION. SPOTTER ACTIVATION MAY BE REQUIRED LATER THIS AFTERNOON. MERZLOCK
Special weather statement, Apr 30, 11:05 AM CDT, 4 hours 7 minutes before
ILZ003>006-008-010>014-019>023-032>033-039-INZ001>005-010>016-019>020- 011100- HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE CHICAGO IL 1100 AM CDT WED APR 30 1997 FOR NORTH CENTRAL AND NORTHEAST ILLINOIS AND NORTHWEST AND NORTH CENTRAL INDIANA ...SEVERE THUNDERSTORMS POSSIBLE THIS AFTERNOON AND EVENING... THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS NORTH CENTRAL AND NORTHEAST ILLINOIS AS WELL AS NORTHERN INDIANA. AT 11 AM CDT THE CENTER OF A STRONG LOW PRESSURE AREA WAS LOCATED OVER NORTH CENTRAL MISSOURI. THE LOW IS EXPECTED TO MOVE NORTHEAST TO NEAR ROCKFORD BY EARLY THIS EVENING...THEN TO NEAR MUSKEGON MICHIGAN BY AROUND MIDNIGHT. THIS MEANS THAT MILD AND MORE MOIST AIR OVER THE MID MISSISSIPPI VALLEY WILL BE DRAWN INTO THE MODERATE RISK AREA PROVIDING THE INGREDIENTS FOR THUNDERSTORM DEVELOPMENT. IN ADDITION...WIND VELOCITIES FROM THE GROUND TO MID LEVELS OF THE ATMOSPHERE WILL BE FAVORABLE FOR SOME OF THESE STORMS TO BECOME TORNADIC. PERSONS ACROSS NORTHERN ILLINOIS AND NORTHERN INDIANA SHOULD STAY ALERT FOR RAPID THUNDERSTORM DEVELOPMENT LATER THIS AFTERNOON AND LISTEN FOR LATER STATEMENTS REGARDING THIS POTENTIALLY SEVERE WEATHER SITUATION. SPOTTER ACTIVATION MAY BE REQUIRED LATER THIS AFTERNOON. MERZLOCK
Special weather statement, Apr 30, 12:59 PM CDT, 2 hours 13 minutes before
ILZ008-010-011-019-301900- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHICAGO IL 100 PM CDT WED APR 30 1997 ...A TORNADO WATCH IS IN EFFECT UNTIL 7 PM CDT... AT 1 PM CDT RADAR INDICATED SCATTERED SHOWERS ACROSS NORTHWEST AND WEST CENTRAL ILLINOIS. THIS AREA OF SHOWERS WAS PRECEDING A LINE OF THUNDERSTORMS THAT CONTINUES TO INTENSIFY ACROSS SOUTHEAST IOWA AND NORTHEAST MISSOURI. THE LINE OF THUNDERSTORMS IS EXPECTED TO BECOME SEVERE AS IT APPROACHES THE MISSISSIPPI RIVER BY 2 PM. THIS LINE SHOULD REACH NORTH CENTRAL ILLINOIS BETWEEN 4 AND 5 PM CDT. PERSONS SHOULD LISTEN FOR LATER STATEMENTS AND POSSIBLE WARNINGS CONCERING THIS SEVERE WEATHER SITUATION AND BE PREPARED TO MOVE QUICKLY TO A PLACE OF SAFETY. MERZLOCK
Special weather statement, Apr 30, 1:00 PM CDT, 2 hours 12 minutes before
ILZ008-010-011-019-301900- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHICAGO IL 100 PM CDT WED APR 30 1997 ...A TORNADO WATCH IS IN EFFECT UNTIL 7 PM CDT... AT 1 PM CDT RADAR INDICATED SCATTERED SHOWERS ACROSS NORTHWEST AND WEST CENTRAL ILLINOIS. THIS AREA OF SHOWERS WAS PRECEDING A LINE OF THUNDERSTORMS THAT CONTINUES TO INTENSIFY ACROSS SOUTHEAST IOWA AND NORTHEAST MISSOURI. THE LINE OF THUNDERSTORMS IS EXPECTED TO BECOME SEVERE AS IT APPROACHES THE MISSISSIPPI RIVER BY 2 PM. THIS LINE SHOULD REACH NORTH CENTRAL ILLINOIS BETWEEN 4 AND 5 PM CDT. PERSONS SHOULD LISTEN FOR LATER STATEMENTS AND POSSIBLE WARNINGS CONCERING THIS SEVERE WEATHER SITUATION AND BE PREPARED TO MOVE QUICKLY TO A PLACE OF SAFETY. MERZLOCK
The office that day
Everything else NWS Chicago, IL issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 30, 2:25 PM CDT | Severe Thunderstorm Warning | LOT | Lee | 35 min |
| Apr 30, 2:41 PM CDT | Tornado Warning | LOT | Lee | 34 min |
| Apr 30, 3:05 PM CDT | Severe Thunderstorm Warning | LOT | LaSalle | 40 min |
| Apr 30, 4:29 PM CDT | Severe Thunderstorm Warning | LOT | Ford, Livingston | 31 min |
| Apr 30, 5:13 PM CDT | Tornado Warning | LOT | Lake | 32 min |
| Apr 30, 5:37 PM CDT | Severe Thunderstorm Warning | LOT | Benton, Jasper, Newton | 53 min |
| Apr 30, 5:44 PM CDT | Tornado Warning | LOT | Pulaski, Starke | 46 min |
| Apr 30, 5:59 PM CDT | Tornado Warning | LOT | Pulaski, White | 31 min |
| Apr 30, 6:10 PM CDT | Tornado Warning | LOT | Marshall, Saint Joseph | 35 min |
| Apr 30, 6:27 PM CDT | Tornado Warning | LOT | Elkhart, Saint Joseph | 33 min |
| Apr 30, 6:44 PM CDT | Severe Thunderstorm Warning | LOT | Elkhart, Kosciusko | 46 min |
Nearby
Severe Thunderstorm Warnings in Illinois, 1997Every severe thunderstorm warning in 1997
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; radar from the NEXRAD Level II archive.