Alert archive / Illinois / Tornado Watches in 1998

Tornado Watch 215

April 15, 199838 counties in Illinois; Lake County, Porter County, Indiana; Allegan County, Berrien County, Van Buren County, Michigan

The Storm Prediction Center issued this tornado watch at Apr 15, 1998, 3:15 PM CDT for 38 counties in Illinois; Lake County, Porter County, Indiana; Allegan County, Berrien County, Van Buren County, Michigan. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Apr 15, 1998, 3:15 PM CDT (20:15 UTC)
Expired
Apr 15, 1998, 9:00 PM CDT
In force
6 hr
Issued by
the Storm Prediction Center
All 43 counties

Boone County, IL, Bureau County, IL, Carroll County, IL, Cook County, IL, DeKalb County, IL, DuPage County, IL, Ford County, IL, Fulton County, IL, Grundy County, IL, Hancock County, IL, Henderson County, IL, Henry County, IL, Iroquois County, IL, Kane County, IL, Kankakee County, IL, Kendall County, IL, Knox County, IL, Lake County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, Marshall County, IL, McDonough County, IL, McHenry County, IL, McLean County, IL, Mercer County, IL, Ogle County, IL, Peoria County, IL, Putnam County, IL, Rock Island County, IL, Stark County, IL, Stephenson County, IL, Tazewell County, IL, Warren County, IL, Whiteside County, IL, Will County, IL, Winnebago County, IL, Woodford County, IL, Lake County, IN, Porter County, IN, Allegan County, MI, Berrien County, MI, Van Buren County, MI

The radar

The Quad Cities radar (KDVN), 105 km from the middle of the area, began a volume at 20:17 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.

Warnings issued inside it

11 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Apr 15, 3:36 PM CDTSevere Thunderstorm WarningDVNHenry, Whiteside49 min
Apr 15, 3:53 PM CDTTornado WarningDVNBureau, Henry, Whiteside32 min
Apr 15, 4:20 PM CDTTornado WarningDVNHenderson, Warren50 min
Apr 15, 4:25 PM CDTTornado WarningDVNBureau50 min
Apr 15, 4:36 PM CDTSevere Thunderstorm WarningLOTLee49 min
Apr 15, 4:38 PM CDTTornado WarningILXKnox37 min
Apr 15, 5:02 PM CDTTornado WarningDVNMercer48 min
Apr 15, 5:19 PM CDTTornado WarningLOTLaSalle, Lee31 min
Apr 15, 8:15 PM CDTSevere Thunderstorm WarningDVNHancock, McDonough50 min
Apr 15, 8:32 PM CDTSevere Thunderstorm WarningILXMcLean43 min
Apr 15, 8:53 PM CDTSevere Thunderstorm WarningILXFulton, Knox52 min

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 8.3 hours before the alert went out and 99 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-pSkew-T log-p diagram, Davenport, at 12:00Z on 1998-04-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Davenport, at 12:00Z on 1998-04-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 344 square meters per square second.1939587897117Sfc1 km3 km6 km9 kmRMLM
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
667 m above ground
0-6 km bulk shear
68 kt
0-1 km storm-relative helicity
344 m²/s²
0-3 km storm-relative helicity
446 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 15, 4:30 PM CDTTornado WatchSPCAlexander, Clay, Clinton, Edwards, Franklin, Gallatin and 22 more7 hr

Nearby

Tornado Watches in Illinois, 1998Tornado Watches in Michigan, 1998Tornado Watches in Indiana, 1998Every tornado watch in 1998

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.