Alert archive / Mississippi / Mesoscale Discussions in 2013

Mesoscale Discussion 765

May 21, 2013Colbert County, Franklin County, Marion County, Alabama; 11 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at May 21, 2013, 9:22 PM CDT for Colbert County, Franklin County, Marion County, Alabama; 11 counties in Mississippi. It was in force for 23 min.

The area

The outline as issued.

The facts

Issued: May 21, 2013, 9:22 PM CDT (02:22 UTC)
Expired: May 21, 2013, 9:45 PM CDT
In force: 23 min
Issued by: the Storm Prediction Center

Counties Colbert County, AL, Franklin County, AL, Marion County, AL, Calhoun County, MS, Chickasaw County, MS, Grenada County, MS, Itawamba County, MS, Lee County, MS, Monroe County, MS, Pontotoc County, MS, Prentiss County, MS, Tishomingo County, MS, Union County, MS, Yalobusha County, MS

The radar

The Columbus AFB radar (KGWX), 51 km from the middle of the area, began a volume at 02:22 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

Little Rock, AR (KLZK), launched 00:00Z, 2.4 hours before the alert went out and 142 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: 57 J/kg
Mixed-layer CIN: -554 J/kg
Mixed-layer LCL: 1175 m above ground
0-6 km bulk shear: 52 kt
0-1 km storm-relative helicity: -47 m²/s²
0-3 km storm-relative helicity: 20 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.0

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 21, 7:39 PM CDT	Mesoscale Discussion	SPC	Adams, Attala, Choctaw, Claiborne, Copiah, Franklin and 17 more	2 hr
May 21, 9:01 PM CDT	Severe Thunderstorm Watch	SPC	Adams, Attala, Bolivar, Carroll, Choctaw, Claiborne and 34 more	5 hr
May 21, 11:41 PM CDT	Mesoscale Discussion	SPC	Adams, Attala, Choctaw, Claiborne, Clay, Copiah and 20 more	64 min

Nearby

Mesoscale Discussions in Mississippi, 2013 Mesoscale Discussions in Alabama, 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.