Alert archive / Missouri / Tornado Watches in 2006

Tornado Watch 203

April 18, 20069 counties in Illinois; 18 counties in Missouri

The Storm Prediction Center issued this tornado watch at Apr 18, 2006, 9:27 PM CDT for 9 counties in Illinois; 18 counties in Missouri. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Apr 18, 2006, 9:27 PM CDT (02:27 UTC)
Expired
Apr 19, 2006, 3:00 AM CDT
In force
6 hr
Issued by
the Storm Prediction Center
All 27 counties

Alexander County, IL, Jackson County, IL, Madison County, IL, Monroe County, IL, Perry County, IL, Pulaski County, IL, Randolph County, IL, Saint Clair County, IL, Union County, IL, Bollinger County, MO, Cape Girardeau County, MO, City of Saint Louis, MO, Franklin County, MO, Iron County, MO, Jefferson County, MO, Madison County, MO, Montgomery County, MO, Perry County, MO, Reynolds County, MO, Saint Charles County, MO, Saint Francois County, MO, Saint Louis County, MO, Sainte Genevieve County, MO, Scott County, MO, Warren County, MO, Washington County, MO, Wayne County, MO

The radar

The St Louis radar (KLSX), 62 km from the middle of the area, began a volume at 02:29 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.

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Apr 18, 9:43 PM CDTSevere Thunderstorm WarningLSXFranklin, Gasconade47 min
Apr 18, 9:44 PM CDTSevere Thunderstorm WarningLSXWarren29 min
Apr 18, 10:12 PM CDTTornado WarningLSXFranklin, Gasconade48 min
Apr 18, 10:53 PM CDTSevere Thunderstorm WarningLSXSaint Charles28 min
Apr 18, 10:58 PM CDTTornado WarningLSXFranklin, Jefferson47 min
Apr 18, 11:35 PM CDTTornado WarningLSXJefferson25 min
Apr 18, 11:46 PM CDTSevere Thunderstorm WarningLSXMonroe44 min
Apr 18, 11:56 PM CDTSevere Thunderstorm WarningLSXCity of Saint Louis12 min
Apr 19, 12:00 AM CDTSevere Thunderstorm WarningLSXRandolph60 min
Apr 19, 12:04 AM CDTSevere Thunderstorm WarningLSXSaint Clair56 min
Apr 19, 12:35 AM CDTSevere Thunderstorm WarningPAHPerry40 min
Apr 19, 1:00 AM CDTSevere Thunderstorm WarningLSXRandolph15 min
Apr 19, 1:05 AM CDTSevere Thunderstorm WarningPAHJackson40 min
Apr 19, 1:17 AM CDTSevere Thunderstorm WarningPAHCape Girardeau28 min
Apr 19, 1:19 AM CDTSevere Thunderstorm WarningPAHScott, Stoddard26 min
Apr 19, 1:29 AM CDTSevere Thunderstorm WarningPAHUnion46 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 2.5 hours before the alert went out and 282 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, Lincoln, IL at 00:00Z on 2006-04-19Temperature 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, Lincoln, IL at 00:00Z on 2006-04-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 64 square meters per square second.193958Sfc1 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
1825 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
64 m²/s²
0-3 km storm-relative helicity
276 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.7

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 18, 8:59 PM CDTMesoscale DiscussionSPCAdams, Brown, Calhoun, Cass, Greene, Hancock and 11 more91 min
Apr 18, 9:15 PM CDTSevere Thunderstorm WatchSPCAdams, Brown, Calhoun, Cass, Greene, Hancock and 7 more4 hr
Apr 18, 10:36 PM CDTMesoscale DiscussionSPCAdams, Brown, Calhoun, Cass, Fulton, Greene and 18 more114 min
Apr 19, 12:00 AM CDTMesoscale DiscussionSPCAlexander, Bond, Clark, Clay, Clinton, Crawford and 23 more60 min
Apr 19, 12:50 AM CDTSevere Thunderstorm WatchSPCChampaign, Clark, Clay, Coles, Crawford, Cumberland and 13 more6 hr
Apr 19, 1:29 AM CDTTornado WatchSPCEdwards, Franklin, Gallatin, Hamilton, Hardin, Jefferson and 8 more4 hr

Nearby

Tornado Watches in Missouri, 2006Tornado Watches in Illinois, 2006Every tornado watch in 2006

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.