Alert archive / Mississippi / Mesoscale Discussions in 2005

Mesoscale Discussion 474

April 1, 2005Saint Helena Parish, Tangipahoa Parish, Washington Parish, Louisiana; 22 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 1, 2005, 4:14 AM CST for Saint Helena Parish, Tangipahoa Parish, Washington Parish, Louisiana; 22 counties in Mississippi. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Apr 1, 2005, 4:14 AM CST (10:14 UTC)
Expired: Apr 1, 2005, 6:15 AM CST
In force: 2 hr
Issued by: the Storm Prediction Center

All 25 counties

Saint Helena Parish, LA, Tangipahoa Parish, LA, Washington Parish, LA, Clarke County, MS, Covington County, MS, Forrest County, MS, George County, MS, Greene County, MS, Jasper County, MS, Jefferson Davis County, MS, Jones County, MS, Kemper County, MS, Lamar County, MS, Lauderdale County, MS, Lawrence County, MS, Marion County, MS, Newton County, MS, Pearl River County, MS, Perry County, MS, Pike County, MS, Simpson County, MS, Smith County, MS, Stone County, MS, Walthall County, MS, Wayne County, MS

The radar

The Jackson/Brandon,MS radar (KDGX), 92 km from the middle of the area, began a volume at 10:17 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, 10.2 hours before the alert went out and 99 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: 98 J/kg
Mixed-layer CIN: -220 J/kg
Mixed-layer LCL: 1744 m above ground
0-6 km bulk shear: 60 kt
0-1 km storm-relative helicity: 4 m²/s²
0-3 km storm-relative helicity: 239 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.6

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 31, 6:49 PM CST	Mesoscale Discussion	SPC	Acadia, Allen, Beauregard, Bienville, Bossier, Caddo and 16 more	56 min
Mar 31, 7:05 PM CST	Severe Thunderstorm Watch	SPC	Bienville, Bossier, Caddo, Caldwell, Claiborne, De Soto and 17 more	5 hr
Mar 31, 8:25 PM CST	Mesoscale Discussion	SPC	Acadia, Calcasieu, Cameron, Jefferson Davis, Vermilion	65 min
Mar 31, 8:45 PM CST	Severe Thunderstorm Watch	SPC	Acadia, Allen, Beauregard, Calcasieu, Cameron, Evangeline and 4 more	7 hr
Mar 31, 8:59 PM CST	Mesoscale Discussion	SPC	Ascension, Catahoula, Concordia, East Baton Rouge, East Feliciana, Iberville and 8 more	61 min
Mar 31, 9:27 PM CST	Mesoscale Discussion	SPC	Bienville, Bossier, Caddo, Caldwell, Claiborne, De Soto and 15 more	63 min
Mar 31, 10:53 PM CST	Mesoscale Discussion	SPC	Avoyelles, Bienville, Bossier, Caddo, Caldwell, Catahoula and 29 more	67 min
Mar 31, 11:15 PM CST	Tornado Watch	SPC	Avoyelles, Bienville, Caldwell, Catahoula, Claiborne, Concordia and 27 more	8 hr
Apr 1, 12:25 AM CST	Mesoscale Discussion	SPC	Acadia, Allen, Beauregard, Calcasieu, Cameron, Jefferson Davis and 3 more	95 min
Apr 1, 1:29 AM CST	Mesoscale Discussion	SPC	Jefferson, Lafourche, Orleans, Plaquemines, Saint Bernard, Saint Tammany	2 hr
Apr 1, 2:05 AM CST	Tornado Watch	SPC	Orleans, Saint Bernard, Saint Tammany, Washington	5 hr
Apr 1, 11:16 AM CST	Mesoscale Discussion	SPC	Alcorn, Benton, Itawamba, Lee, Pontotoc, Prentiss and 3 more	2 hr
Apr 1, 11:20 AM CST	Mesoscale Discussion	SPC	Clarke, Jasper, Jones, Kemper, Lauderdale, Lowndes and 9 more	115 min
Apr 1, 11:45 AM CST	Severe Thunderstorm Watch	SPC	Alcorn, Chickasaw, Clay, Itawamba, Kemper, Lauderdale and 10 more	6 hr
Apr 1, 3:19 PM CST	Mesoscale Discussion	SPC	George, Greene, Perry, Stone, Wayne	116 min

Nearby

Mesoscale Discussions in Mississippi, 2005 Mesoscale Discussions in Louisiana, 2005 Every mesoscale discussion in 2005

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.