Alert archive / Missouri / Mesoscale Discussions in 2013

Mesoscale Discussion 737

May 20, 2013Calhoun County, Pike County, Illinois; 21 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at May 20, 2013, 8:07 PM CDT for Calhoun County, Pike County, Illinois; 21 counties in Missouri. It was in force for 23 min.

The area

The outline as issued.

The facts

Issued: May 20, 2013, 8:07 PM CDT (01:07 UTC)
Expired: May 20, 2013, 8:30 PM CDT
In force: 23 min
Issued by: the Storm Prediction Center

All 23 counties

Calhoun County, IL, Pike County, IL, Audrain County, MO, Callaway County, MO, Christian County, MO, Cole County, MO, Douglas County, MO, Gasconade County, MO, Laclede County, MO, Lincoln County, MO, Maries County, MO, Miller County, MO, Montgomery County, MO, Osage County, MO, Phelps County, MO, Pike County, MO, Pulaski County, MO, Ralls County, MO, Stone County, MO, Taney County, MO, Warren County, MO, Webster County, MO, Wright County, MO

The radar

The Springfield radar (KSGF), 136 km from the middle of the area, began a volume at 01:09 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 nearest sounding before it

Springfield, MO (KSGF), launched 00:00Z, 1.1 hours before the alert went out and 187 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: 2135 J/kg
Mixed-layer CIN: -10 J/kg
Mixed-layer LCL: 780 m above ground
0-6 km bulk shear: 49 kt
0-1 km storm-relative helicity: 236 m²/s²
0-3 km storm-relative helicity: 265 m²/s²
Significant tornado parameter: 3.2
Supercell composite: 13.9

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 20, 7:17 PM CDT	Mesoscale Discussion	SPC	Boone, Bureau, Carroll, DeKalb, DeWitt, DuPage and 25 more	58 min
May 20, 7:39 PM CDT	Tornado Watch	SPC	Randolph	6 hr
May 20, 7:48 PM CDT	Severe Thunderstorm Watch	SPC	Boone, Bureau, Carroll, Cook, DeKalb, DuPage and 20 more	6 hr
May 20, 8:53 PM CDT	Mesoscale Discussion	SPC	Adams, Bond, Brown, Calhoun, Cass, Christian and 27 more	67 min
May 20, 10:25 PM CDT	Mesoscale Discussion	SPC	Alexander, Champaign, Clark, Clay, Coles, Crawford and 33 more	65 min
May 20, 10:56 PM CDT	Tornado Watch	SPC	Alexander, Champaign, Clark, Clay, Coles, Crawford and 29 more	6 hr
May 21, 2:59 AM CDT	Mesoscale Discussion	SPC	Alexander, Franklin, Gallatin, Hamilton, Hardin, Johnson and 7 more	91 min
May 21, 12:50 AM CDT	Severe Thunderstorm Watch	SPC	Dunklin, Pemiscot	3 hr
May 21, 7:47 AM CDT	Mesoscale Discussion	SPC	Dunklin, Pemiscot	58 min
May 21, 2:42 PM CDT	Mesoscale Discussion	SPC	Dunklin, Pemiscot	63 min
May 21, 3:00 PM CDT	Tornado Watch	SPC	Dunklin, Pemiscot	7 hr

Nearby

Mesoscale Discussions in Missouri, 2013 Mesoscale Discussions in Illinois, 2013 Every mesoscale discussion in 2013

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.