Alert archive / Mississippi / Mesoscale Discussions in 2013

Mesoscale Discussion 201

February 21, 2013Choctaw County, Washington County, Alabama; 6 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Feb 21, 2013, 11:57 PM CST for Choctaw County, Washington County, Alabama; 6 counties in Mississippi. It was in force for 63 min.

The area

The outline as issued.

The facts

Issued: Feb 21, 2013, 11:57 PM CST (05:57 UTC)
Expired: Feb 22, 2013, 1:00 AM CST
In force: 63 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

Counties Choctaw County, AL, Washington County, AL, Forrest County, MS, George County, MS, Greene County, MS, Perry County, MS, Stone County, MS, Wayne County, MS

The radar

The Mobile radar (KMOB), 86 km from the middle of the area, began a volume at 06:00 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

Slidell Radar S, LA (KSIL), launched 00:00Z, 6.0 hours before the alert went out and 171 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: 421 J/kg
Mixed-layer CIN: -16 J/kg
Mixed-layer LCL: 524 m above ground
0-6 km bulk shear: 62 kt
0-1 km storm-relative helicity: 640 m²/s²
0-3 km storm-relative helicity: 752 m²/s²
Significant tornado parameter: 1.8
Supercell composite: 11.8

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
Feb 22, 1:28 PM CST	Mesoscale Discussion	SPC	Choctaw, Clarke, Marengo, Monroe, Washington, Wilcox	62 min
Feb 21, 8:53 PM CST	Mesoscale Discussion	SPC	Amite, Copiah, Covington, Forrest, Franklin, Jefferson Davis and 10 more	67 min
Feb 21, 10:53 PM CST	Mesoscale Discussion	SPC	Amite, Covington, Forrest, Jefferson Davis, Jones, Lamar and 6 more	67 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.