Alert archive / Louisiana / Mesoscale Discussions in 2013

Mesoscale Discussion 173

February 18, 20135 states

The Storm Prediction Center issued this mesoscale discussion at Feb 18, 2013, 8:26 PM CST for 5 states. It was in force for 64 min.

The area

The outline as issued.

The facts

Issued: Feb 18, 2013, 8:26 PM CST (02:26 UTC)
Expired: Feb 18, 2013, 9:30 PM CST
In force: 64 min
Issued by: the Storm Prediction Center

All 31 counties

Chicot County, AR, Caldwell Parish, LA, East Carroll Parish, LA, Franklin Parish, LA, Grant Parish, LA, Jackson Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Richland Parish, LA, Sabine Parish, LA, West Carroll Parish, LA, Winn Parish, LA, Benton County, MS, Humphreys County, MS, Issaquena County, MS, Lafayette County, MS, Leflore County, MS, Marshall County, MS, Panola County, MS, Sharkey County, MS, Sunflower County, MS, Tallahatchie County, MS, Washington County, MS, Yalobusha County, MS, Carroll County, TN, Chester County, TN, Hardeman County, TN, Madison County, TN, Sabine County, TX, Tyler County, TX

The radar

The Jackson/Brandon,MS radar (KDGX), 175 km from the middle of the area, began a volume at 02:25 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

Shreveport, LA (KSHV), launched 00:00Z, 2.4 hours before the alert went out and 217 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: 800 J/kg
Mixed-layer CIN: -11 J/kg
Mixed-layer LCL: 593 m above ground
0-6 km bulk shear: 67 kt
0-1 km storm-relative helicity: 361 m²/s²
0-3 km storm-relative helicity: 392 m²/s²
Significant tornado parameter: 2.0
Supercell composite: 6.8

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 18, 6:47 PM CST	Mesoscale Discussion	SPC	Crittenden, Mississippi	88 min

Nearby

Mesoscale Discussions in Louisiana, 2013 Mesoscale Discussions in Mississippi, 2013 Mesoscale Discussions in Tennessee, 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.