Alert archive / Louisiana / Mesoscale Discussions in 2003

Mesoscale Discussion 274

March 18, 200319 parishes in Louisiana

The Storm Prediction Center issued this mesoscale discussion at Mar 18, 2003, 1:12 PM CST for 19 parishes in Louisiana. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Mar 18, 2003, 1:12 PM CST (19:12 UTC)
Expired: Mar 18, 2003, 3:15 PM CST
In force: 2 hr
Issued by: the Storm Prediction Center

Counties Bienville Parish, LA, Caldwell Parish, LA, Catahoula Parish, LA, De Soto Parish, LA, Franklin Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Red River Parish, LA, Richland Parish, LA, Sabine Parish, LA, Union Parish, LA, Vernon Parish, LA, West Carroll Parish, LA, Winn Parish, LA

The watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Tornado Watch 52Mar 18, 2:15 PM CST

The nearest sounding before it

Shreveport, LA (KSHV), launched 12:00Z, 7.2 hours before the alert went out and 104 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: 29 J/kg
Mixed-layer CIN: -184 J/kg
Mixed-layer LCL: 707 m above ground
0-6 km bulk shear: 52 kt
0-1 km storm-relative helicity: 99 m²/s²
0-3 km storm-relative helicity: 132 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
Mar 18, 9:36 AM CST	Mesoscale Discussion	SPC	Bossier, Caddo, De Soto, Red River, Sabine, Webster	3 hr
Mar 18, 11:40 AM CST	Tornado Watch	SPC	Allen, Beauregard, Calcasieu, Cameron, Grant, Natchitoches and 2 more	5 hr
Mar 18, 2:15 PM CST	Tornado Watch	SPC	Acadia, Allen, Avoyelles, Beauregard, Bienville, Calcasieu and 28 more	7 hr
Mar 18, 3:33 PM CST	Mesoscale Discussion	SPC	Bienville, Caldwell, Catahoula, De Soto, Franklin, Grant and 13 more	57 min
Mar 18, 4:30 PM CST	Mesoscale Discussion	SPC	Ascension, East Baton Rouge, East Carroll, East Feliciana, Livingston, Madison and 8 more	2 hr
Mar 18, 5:05 PM CST	Tornado Watch	SPC	Ascension, East Baton Rouge, East Feliciana, Iberville, Livingston, Saint Helena and 4 more	6 hr

Nearby

Mesoscale Discussions in Louisiana, 2003 Every mesoscale discussion in 2003

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.