Alert archive / Missouri / Mesoscale Discussions in 2009

Mesoscale Discussion 751

May 7, 200919 counties in Illinois; 40 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at May 7, 2009, 9:38 PM CDT for 19 counties in Illinois; 40 counties in Missouri. It was in force for 97 min.

The area

The outline as issued.

The facts

Issued: May 7, 2009, 9:38 PM CDT (02:38 UTC)
Expired: May 7, 2009, 11:15 PM CDT
In force: 97 min
Issued by: the Storm Prediction Center

All 59 counties

Clinton County, IL, Franklin County, IL, Gallatin County, IL, Hamilton County, IL, Jackson County, IL, Jefferson County, IL, Johnson County, IL, Madison County, IL, Marion County, IL, Monroe County, IL, Perry County, IL, Randolph County, IL, Saint Clair County, IL, Saline County, IL, Union County, IL, Washington County, IL, Wayne County, IL, White County, IL, Williamson County, IL, Audrain County, MO, Benton County, MO, Bollinger County, MO, Boone County, MO, Callaway County, MO, Camden County, MO, Cape Girardeau County, MO, City of Saint Louis, MO, Cole County, MO, Cooper County, MO, Crawford County, MO, Dallas County, MO, Dent County, MO, Franklin County, MO, Gasconade County, MO, Hickory County, MO, Howard County, MO, Iron County, MO, Jefferson County, MO, Laclede County, MO, Lincoln County, MO, Madison County, MO, Maries County, MO, Miller County, MO, Moniteau County, MO, Montgomery County, MO, Morgan County, MO, Osage County, MO, Perry County, MO, Pettis County, MO, Phelps County, MO, Pulaski County, MO, Reynolds County, MO, Saint Charles County, MO, Saint Francois County, MO, Saint Louis County, MO, Sainte Genevieve County, MO, Saline County, MO, Warren County, MO, Washington County, MO

The radar

The St Louis radar (KLSX), 73 km from the middle of the area, began a volume at 02:39 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 262May 7, 10:15 PM CDT

The nearest sounding before it

Springfield, MO (KSGF), launched 00:00Z, 2.6 hours before the alert went out and 268 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: 684 J/kg
Mixed-layer CIN: -40 J/kg
Mixed-layer LCL: 1765 m above ground
0-6 km bulk shear: 56 kt
0-1 km storm-relative helicity: 94 m²/s²
0-3 km storm-relative helicity: 219 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 7.3

Open this sounding in Storm Lab

The text

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

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 7, 10:17 PM CDT	Severe Thunderstorm Watch	SPC	Alexander, Franklin, Gallatin, Hardin, Jackson, Johnson and 9 more	8 hr
May 7, 11:46 PM CDT	Mesoscale Discussion	SPC	Alexander, Bond, Clark, Clay, Clinton, Coles and 33 more	89 min
May 8, 3:34 AM CDT	Mesoscale Discussion	SPC	Alexander, Massac, Pulaski	56 min
May 8, 8:37 AM CDT	Mesoscale Discussion	SPC	Alexander, Massac, Pulaski	53 min
May 8, 9:21 AM CDT	Tornado Watch	SPC	Alexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 14 more	7 hr
May 8, 2:16 PM CDT	Mesoscale Discussion	SPC	Edwards, Franklin, Gallatin, Hamilton, Jefferson, Saline and 3 more	89 min
May 8, 5:47 PM CDT	Mesoscale Discussion	SPC	Boone, Bureau, Carroll, Henderson, Henry, Jo Daviess and 9 more	58 min
May 8, 6:10 PM CDT	Severe Thunderstorm Watch	SPC	Bureau, Carroll, Henderson, Henry, Jo Daviess, Knox and 13 more	4 hr
May 7, 7:37 PM CDT	Severe Thunderstorm Watch	SPC	Adair, Andrew, Atchison, Buchanan, Caldwell, Carroll and 25 more	6 hr
May 8, 4:31 AM CDT	Mesoscale Discussion	SPC	Barry, Barton, Cedar, Christian, Dade, Dallas and 11 more	59 min
May 8, 4:55 AM CDT	Severe Thunderstorm Watch PDS	SPC	Barry, Barton, Benton, Camden, Cedar, Christian and 28 more	7 hr
May 8, 7:17 AM CDT	Mesoscale Discussion	SPC	Barry, Barton, Christian, Dade, Douglas, Greene and 10 more	58 min
May 8, 11:08 AM CDT	Mesoscale Discussion	SPC	Christian, Douglas, Howell, Ozark, Taney, Texas and 1 more	67 min
May 8, 3:42 PM CDT	Tornado Watch	SPC	Dunklin, Pemiscot	7 hr

Nearby

Mesoscale Discussions in Missouri, 2009 Mesoscale Discussions in Illinois, 2009 Every mesoscale discussion in 2009

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.