Alert archive / Illinois / Severe Thunderstorm Watches in 2000

Severe Thunderstorm Watch 183

April 20, 200034 counties in Illinois; Scott County, Iowa

The Storm Prediction Center issued this severe thunderstorm watch at Apr 20, 2000, 12:45 AM CDT for 34 counties in Illinois; Scott County, Iowa. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Apr 20, 2000, 12:45 AM CDT (05:45 UTC)
Expired
Apr 20, 2000, 6:00 AM CDT
In force
5 hr
Issued by
the Storm Prediction Center
All 35 counties

Scott County, IA, Boone County, IL, Bureau County, IL, Carroll County, IL, Cook County, IL, DeKalb County, IL, DuPage County, IL, Fulton County, IL, Grundy County, IL, Henderson County, IL, Henry County, IL, Jo Daviess County, IL, Kane County, IL, Kendall County, IL, Knox County, IL, Lake County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, Marshall 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

The radar

The Quad Cities radar (KDVN), 81 km from the middle of the area, began a volume at 05:45 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

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

IssuedProductOfficeCountiesLasted
Apr 20, 12:50 AM CDTSevere Thunderstorm WarningDVNHenderson40 min
Apr 20, 1:22 AM CDTSevere Thunderstorm WarningLOTFord, Livingston38 min
Apr 20, 1:30 AM CDTSevere Thunderstorm WarningDVNWarren45 min
Apr 20, 1:34 AM CDTSevere Thunderstorm WarningILXKnox41 min
Apr 20, 1:46 AM CDTSevere Thunderstorm WarningDVNHenry34 min
Apr 20, 2:03 AM CDTSevere Thunderstorm WarningILXStark42 min
Apr 20, 4:46 AM CDTSevere Thunderstorm WarningDVNHenderson, Mercer, Warren44 min
Apr 20, 4:56 AM CDTSevere Thunderstorm WarningILXKnox49 min
Apr 20, 5:09 AM CDTSevere Thunderstorm WarningDVNHenry, Rock Island51 min
Apr 20, 5:21 AM CDTSevere Thunderstorm WarningILXFulton, Mason54 min
Apr 20, 5:33 AM CDTSevere Thunderstorm WarningILXStark27 min
Apr 20, 5:45 AM CDTSevere Thunderstorm WarningLOTGrundy, Kendall, Will30 min
Apr 20, 5:47 AM CDTSevere Thunderstorm WarningILXLogan, Peoria, Tazewell43 min

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 5.8 hours before the alert went out and 75 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 00:00Z on 2000-04-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 4 joules per kilogram.LCLLFCEL10008507005003002001001 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 00:00Z on 2000-04-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 471 square meters per square second.1939587897Sfc1 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
4 J/kg
Mixed-layer CIN
-616 J/kg
Mixed-layer LCL
865 m above ground
0-6 km bulk shear
66 kt
0-1 km storm-relative helicity
471 m²/s²
0-3 km storm-relative helicity
491 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

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 19, 8:45 PM CDTSevere Thunderstorm WatchSPCJo Daviess4 hr
Apr 19, 10:00 PM CDTTornado WatchSPCAdams, Brown, Cass, Fulton, Hancock, McDonough and 3 more6 hr
Apr 20, 3:15 AM CDTSevere Thunderstorm WatchSPCAlexander, Jackson, Perry, Randolph, Union5 hr
Apr 20, 4:15 AM CDTSevere Thunderstorm WatchSPCAdams, Bond, Boone, Brown, Bureau, Calhoun and 61 more6 hr
Apr 20, 10:00 AM CDTTornado WatchSPCBond, Champaign, Clark, Clay, Clinton, Coles and 30 more6 hr

Nearby

Severe Thunderstorm Watches in Illinois, 2000Severe Thunderstorm Watches in Iowa, 2000Every severe thunderstorm watch in 2000

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.