Alert archive / Illinois / Severe Thunderstorm Watches in 2016

Severe Thunderstorm Watch 145

May 7, 201632 counties in Illinois; 5 counties in Missouri

The Storm Prediction Center issued this severe thunderstorm watch at May 7, 2016, 3:42 PM CDT for 32 counties in Illinois; 5 counties in Missouri. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: May 7, 2016, 3:42 PM CDT (20:42 UTC)
Expired: May 7, 2016, 8:14 PM CDT
In force: 5 hr
Issued by: the Storm Prediction Center
Largest hail expected: 1.5 in
Strongest gust expected: 60 kt

All 37 counties

Bond County, IL, Calhoun County, IL, Christian County, IL, Clark County, IL, Clay County, IL, Clinton County, IL, Crawford County, IL, Cumberland County, IL, Edwards County, IL, Effingham County, IL, Fayette County, IL, Greene County, IL, Hamilton County, IL, Jasper County, IL, Jefferson County, IL, Jersey County, IL, Lawrence County, IL, Macoupin County, IL, Madison County, IL, Marion County, IL, Monroe County, IL, Montgomery County, IL, Morgan County, IL, Richland County, IL, Saint Clair County, IL, Sangamon County, IL, Scott County, IL, Shelby County, IL, Wabash County, IL, Washington County, IL, Wayne County, IL, White County, IL, City of Saint Louis, MO, Jefferson County, MO, Lincoln County, MO, Saint Charles County, MO, Saint Louis County, MO

The radar

The St Louis radar (KLSX), 112 km from the middle of the area, began a volume at 20:45 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.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes: 10%
One or more EF2 to EF5 tornadoes: 2%
Ten or more severe wind reports: 50%
One or more gusts of 65 knots or more: 10%
Ten or more severe hail reports: 30%
One or more hailstones of 2 inches or more: 10%
Six or more combined severe hail and wind reports: 70%

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
May 7, 3:55 PM CDT	Severe Thunderstorm Warning	LSX	Calhoun, Greene, Jersey, Macoupin, Madison	50 min
May 7, 4:24 PM CDT	Severe Thunderstorm Warning	LSX	Madison	36 min
May 7, 4:36 PM CDT	Severe Thunderstorm Warning	LSX	Bond, Macoupin, Madison, Montgomery	24 min
May 7, 4:58 PM CDT	Severe Thunderstorm Warning	LSX	Bond, Clinton, Fayette, Madison, Montgomery, Saint Clair	47 min
May 7, 5:26 PM CDT	Severe Thunderstorm Warning	LSX	Washington	34 min
May 7, 5:27 PM CDT	Severe Thunderstorm Warning	LSX	Marion	37 min
May 7, 5:33 PM CDT	Severe Thunderstorm Warning	PAH	Jefferson	42 min
May 7, 5:41 PM CDT	Severe Thunderstorm Warning	ILX	Clay, Effingham, Jasper	34 min
May 7, 5:51 PM CDT	Severe Thunderstorm Warning	PAH	Hamilton, Wayne	39 min
May 7, 5:59 PM CDT	Severe Thunderstorm Warning	ILX	Clark, Crawford	46 min
May 7, 6:07 PM CDT	Severe Thunderstorm Warning	ILX	Clay, Crawford, Jasper, Lawrence, Richland	53 min
May 7, 6:13 PM CDT	Severe Thunderstorm Warning	PAH	Edwards, Wabash, White	47 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 12:00Z, 8.7 hours before the alert went out and 148 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: 1 J/kg
Mixed-layer CIN: -438 J/kg
Mixed-layer LCL: 2063 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 228 m²/s²
0-3 km storm-relative helicity: 255 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 7, 1:45 PM CDT	Mesoscale Discussion	SPC	Bond, Christian, Clark, Clay, Coles, Crawford and 17 more	3 hr
May 7, 5:32 PM CDT	Mesoscale Discussion	SPC	Bond, Calhoun, Christian, Clark, Clay, Clinton and 40 more	118 min
May 7, 6:08 PM CDT	Severe Thunderstorm Watch	SPC	Franklin, Gallatin, Saline	6 hr

Nearby

Severe Thunderstorm Watches in Illinois, 2016 Severe Thunderstorm Watches in Missouri, 2016 Every severe thunderstorm watch in 2016

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.