Alert archive / Mississippi / Mesoscale Discussions in 2012

Mesoscale Discussion 1757

August 13, 2012East Carroll Parish, West Carroll Parish, Louisiana; 25 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Aug 13, 2012, 9:17 PM CDT for East Carroll Parish, West Carroll Parish, Louisiana; 25 counties in Mississippi. It was in force for 88 min.

The area

The outline as issued.

The facts

Issued: Aug 13, 2012, 9:17 PM CDT (02:17 UTC)
Expired: Aug 13, 2012, 10:45 PM CDT
In force: 88 min
Issued by: the Storm Prediction Center

All 27 counties

East Carroll Parish, LA, West Carroll Parish, LA, Attala County, MS, Calhoun County, MS, Carroll County, MS, Chickasaw County, MS, Choctaw County, MS, Clay County, MS, Grenada County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Leake County, MS, Leflore County, MS, Lowndes County, MS, Madison County, MS, Montgomery County, MS, Neshoba County, MS, Noxubee County, MS, Oktibbeha County, MS, Sharkey County, MS, Sunflower County, MS, Washington County, MS, Webster County, MS, Winston County, MS, Yalobusha County, MS, Yazoo County, MS

The radar

The Jackson/Brandon,MS radar (KDGX), 107 km from the middle of the area, began a volume at 02:20 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

Jackson, MS (KJAN), launched 00:00Z, 2.3 hours before the alert went out and 106 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: 1249 J/kg
Mixed-layer CIN: -31 J/kg
Mixed-layer LCL: 1706 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 32 m²/s²
0-3 km storm-relative helicity: 90 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.9

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
Aug 13, 7:59 PM CDT	Severe Thunderstorm Watch	SPC	East Carroll, Franklin, Madison, Morehouse, Richland, Tensas and 1 more	7 hr
Aug 13, 11:46 PM CDT	Mesoscale Discussion	SPC	Hinds, Holmes, Humphreys, Kemper, Lauderdale, Leake and 7 more	89 min

Nearby

Mesoscale Discussions in Mississippi, 2012 Mesoscale Discussions in Louisiana, 2012 Every mesoscale discussion in 2012

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.