Alert archive / Illinois / Tornado Warnings in 2003

Tornado Warning 2, NWS Chicago, IL

April 30, 2003LaSalle County, Illinois

NWS Chicago, IL issued this tornado warning at Apr 30, 2003, 10:27 PM CDT for LaSalle County, Illinois. It was in force for 33 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Apr 30, 2003, 10:27 PM CDT (03:27 UTC)
Expired: Apr 30, 2003, 11:00 PM CDT
In force: 33 min
Issued by: NWS Chicago, IL
Area: Counties, with a storm outline in the text

County LaSalle County, IL

The radar

The Chicago radar (KLOT), 89 km from the middle of the area, began a volume at 03:29 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, 5:50 PM CDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 3.5 hours before the alert went out and 127 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: 1022 J/kg
Mixed-layer CIN: -104 J/kg
Mixed-layer LCL: 839 m above ground
0-6 km bulk shear: 63 kt
0-1 km storm-relative helicity: 457 m²/s²
0-3 km storm-relative helicity: 611 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 12.6

Open this sounding in Storm Lab

The text

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

833 
WFUS53 KLOT 010327
TORLOT
ILC099-010400-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE CHICAGO IL
1030 PM CDT WED APR 30 2003

THE NATIONAL WEATHER SERVICE IN CHICAGO HAS ISSUED A

* TORNADO WARNING FOR...
  LA SALLE COUNTY IN NORTH CENTRAL ILLINOIS

* UNTIL 1100 PM CDT

* AT 1025 PM CDT...DOPPLER RADAR INDICATED STRONG ROTATION IN A
  SEVERE THUNDERSTORM NEAR 3 MILES SOUTHWEST OF CEDAR POINT...OR
  ABOUT 7 MILES SOUTHWEST OF OGLESBY...MOVING EAST AT 35 MPH. WALL 
  CLOUDS HAVE ALSO BEEN SPOTTED SOUTHWEST OF THE TOWN OF LASALLE.

* THE STORM WILL BE NEAR...
  TONICA AROUND 1030 PM CDT.
  OGLESBY AROUND 1035 PM CDT.
  NORTH UTICA AROUND 1040 PM CDT.
  STREATOR AROUND 1045 PM CDT.
  NAPLATE AROUND 1050 PM CDT.
  EARLVILLE AROUND 1055 PM CDT.

GO TO THE BASEMENT AND SEEK SHELTER UNDER THE STAIRS OR UNDER A HEAVY
PIECE OF FURNITURE. IF NO BASEMENT IS AVAILABLE...SEEK SHELTER IN AN
INTERIOR CLOSET...BATHROOM...OR HALLWAY ON THE LOWEST FLOOR. STAY
AWAY FROM WINDOWS. REPORT SEVERE WEATHER TO THE NEAREST LAW
ENFORCEMENT AGENCY. THEY WILL RELAY YOUR REPORT TO THE NATIONAL
WEATHER SERVICE.

LAT...LON 4127 8941 4110 8936 4105 8894 4111 8889
          4113 8862 4164 8863 4163 8916
$$

ROGOWSKI/RATZER

NNNN

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 30, 9:39 PM CDT	Severe Thunderstorm Warning	LOT	Cook, Will	51 min
Apr 30, 9:46 PM CDT	Tornado Warning	LOT	LaSalle	44 min
Apr 30, 10:48 PM CDT	Severe Thunderstorm Warning	LOT	Livingston	57 min
Apr 30, 10:58 PM CDT	Severe Thunderstorm Warning	LOT	Grundy, Kendall, LaSalle	47 min
Apr 30, 11:28 PM CDT	Severe Thunderstorm Warning	LOT	DuPage, Kankakee, Will	62 min
Apr 30, 11:35 PM CDT	Special Marine Warning	LOT		85 min
Apr 30, 11:35 PM CDT	Special Marine Warning	LOT		85 min
Apr 30, 11:35 PM CDT	Special Marine Warning	LOT		85 min
May 1, 1:56 AM CDT	Severe Thunderstorm Warning	LOT	Livingston	34 min

Nearby

Tornado Warnings in Illinois, 2003 Every tornado warning in 2003 Tornadoes in 2003

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.