Alert archive / Louisiana / Mesoscale Discussions in 2014

Mesoscale Discussion 129

February 20, 20144 states

The Storm Prediction Center issued this mesoscale discussion at Feb 20, 2014, 6:55 PM CST for 4 states. It was in force for 95 min.

The area

The outline as issued.

The facts

Issued: Feb 20, 2014, 6:55 PM CST (00:55 UTC)
Expired: Feb 20, 2014, 8:30 PM CST
In force: 95 min
Issued by: the Storm Prediction Center

All 35 counties

Chicot County, AR, Allen Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Caldwell Parish, LA, Catahoula Parish, LA, East Carroll Parish, LA, Franklin Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Rapides Parish, LA, Richland Parish, LA, Sabine Parish, LA, Vernon Parish, LA, West Carroll Parish, LA, Winn Parish, LA, Bolivar County, MS, Carroll County, MS, Humphreys County, MS, Issaquena County, MS, Leflore County, MS, Sharkey County, MS, Sunflower County, MS, Washington County, MS, Hardin County, TX, Jasper County, TX, Newton County, TX, Orange County, TX, Sabine County, TX, Tyler County, TX

The radar

The Ft Polk radar (KPOE), 97 km from the middle of the area, began a volume at 00:58 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

Lake Charles Mun, LA (KLCH), launched 00:00Z, 0.9 hours before the alert went out and 210 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: 2092 J/kg
Mixed-layer CIN: -14 J/kg
Mixed-layer LCL: 438 m above ground
0-6 km bulk shear: 47 kt
0-1 km storm-relative helicity: 141 m²/s²
0-3 km storm-relative helicity: 134 m²/s²
Significant tornado parameter: 1.7
Supercell composite: 7.1

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 20, 6:05 PM CST	Tornado Watch	SPC	East Feliciana, Pointe Coupee, Saint Helena, Saint Landry, Tangipahoa, Washington and 1 more	7 hr
Feb 20, 7:22 PM CST	Tornado Watch	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 32 more	8 hr
Feb 20, 9:56 PM CST	Mesoscale Discussion	SPC	Acadia, Ascension, Assumption, Avoyelles, Cameron, Concordia and 26 more	2 hr
Feb 20, 11:43 PM CST	Mesoscale Discussion	SPC	Saint Helena, Washington	62 min
Feb 20, 8:01 PM CST	Mesoscale Discussion	SPC	Itawamba, Tishomingo	89 min
Feb 21, 12:58 AM CST	Severe Thunderstorm Watch	SPC	George, Greene	7 hr

Nearby

Mesoscale Discussions in Louisiana, 2014 Mesoscale Discussions in Mississippi, 2014 Mesoscale Discussions in Texas, 2014 Every mesoscale discussion in 2014

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.