Alert archive / Illinois / Tornado Warnings in 1997

Tornado Warning 7, NWS Chicago, IL

May 18, 1997Lee County, Illinois

NWS Chicago, IL issued this tornado warning at May 18, 1997, 6:45 PM CDT for Lee County, Illinois. It was in force for 60 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 18, 1997, 6:45 PM CDT (23:45 UTC)
Expired: May 18, 1997, 7:45 PM CDT
In force: 60 min
Issued by: NWS Chicago, IL
Area: Whole counties

County Lee County, IL

The radar

The Chicago radar (KLOT), 102 km from the middle of the area, began a volume at 23:46 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.

What was reported inside it

Time	Report	Where	Remark
May 18, 7:15 PM CDT	Hail 1.75	Amboy, IL	Three quarter inch diameter hail fell at Amboy and golf ball size hail fell at Paw Paw.

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.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
May 18, 5:30 PM CDT	Tornado Watch	SPC	6 hr

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 11.8 hours before the alert went out and 101 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.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1986 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: 266 m²/s²
0-3 km storm-relative helicity: 293 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

662 
WFUS1 KCHI 182343 RRA
TORCHI
ILC103-190045-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE CHICAGO IL
645 PM CDT SUN MAY 18 1997

THE NATIONAL WEATHER SERVICE IN CHICAGO HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  745 PM CDT
FOR PEOPLE IN THE FOLLOWING LOCATION...

IN NORTH CENTRAL ILLINOIS

   ...NORTHERN LEE COUNTY

AT 635 PM CDT RADAR INDICATED A SEVERE THUNDERSTORM IN NORTHWEST LEE
COUNTY NEAR PALMYRA.  3 FUNNEL CLOUDS WERE OBSERVED AT THE DIXON TOLL
PLAZA.
THE STORM WAS MOVING TO THE EAST AT 35 MPH.

SOME TOWNS IN THE PATH OF THIS STORM INCLUDE...DIXON...ASHTON...AND
STEWARD.

GO INSIDE A STURDY BUILDING AND STAY AWAY FROM WINDOWS  A TORNADO
WATCH IS IN EFFECT.

&

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, May 18, 1:48 PM CDT, 4 hours 57 minutes before

ILZ003>006-008-010>014-019>023-032>033-039-INZ001>005-010>016-019>020-
191000-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHICAGO IL
1 45 PM CDT SUN MAY 18 1997

SEVERE THUNDERSTORM WATCH NUMBER 294 IS NO LONGER IN EFFECT
FOR LAKE...PORTER...JASPER...NEWTON AND BENTON COUNTIES
IN EXTREME NORTHWEST INDIANA.

ALTHOUGH SCATTERED THUNDERSTORMS ARE STILL OCCURRING IN THIS AREA
THEY ARE NO LONGER EXPECTED TO BE SEVERE.

HOWEVER THERE IS STILL A CHANCE OF SEVERE THUNDERSTORMS THIS EVENING
OR EARLY TONIGHT AS A COOL FRONT APPROACHES THE AREA FROM THE
NORTHWEST.

MORRISON

The office that day

Everything else NWS Chicago, IL issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 18, 5:51 PM CDT	Severe Thunderstorm Warning	LOT	Ogle	69 min
May 18, 6:30 PM CDT	Severe Thunderstorm Warning	LOT	Boone	45 min
May 18, 6:41 PM CDT	Severe Thunderstorm Warning	LOT	Lee	64 min
May 18, 6:56 PM CDT	Severe Thunderstorm Warning	LOT	Lake, McHenry	64 min

Nearby

Tornado Warnings in Illinois, 1997 Every tornado warning in 1997 Tornadoes 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.