Alert archive / Mississippi / Mesoscale Discussions in 2013

Mesoscale Discussion 1992

October 31, 20136 parishes in Louisiana; 25 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Oct 31, 2013, 12:12 PM CDT for 6 parishes in Louisiana; 25 counties in Mississippi. It was in force for 93 min.

The area

The outline as issued.

The facts

Issued: Oct 31, 2013, 12:12 PM CDT (17:12 UTC)
Expired: Oct 31, 2013, 1:45 PM CDT
In force: 93 min
Issued by: the Storm Prediction Center
Chance of a watch: 80%

All 31 counties

Ascension Parish, LA, Livingston Parish, LA, Saint Helena Parish, LA, Saint Tammany Parish, LA, Tangipahoa Parish, LA, Washington Parish, LA, Amite County, MS, Attala County, MS, Clarke County, MS, Copiah County, MS, Covington County, MS, Forrest County, MS, Hinds County, MS, Jasper County, MS, Jefferson Davis County, MS, Jones County, MS, Lamar County, MS, Lawrence County, MS, Leake County, MS, Lincoln County, MS, Madison County, MS, Marion County, MS, Neshoba County, MS, Newton County, MS, Pearl River County, MS, Pike County, MS, Rankin County, MS, Scott County, MS, Simpson County, MS, Smith County, MS, Walthall County, MS

The radar

The Jackson/Brandon,MS radar (KDGX), 72 km from the middle of the area, began a volume at 17:13 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 watches that followed

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

Tornado Watch 552Oct 31, 12:30 PM CDT

The nearest sounding before it

Jackson, MS (KJAN), launched 12:00Z, 5.2 hours before the alert went out and 77 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: 26 J/kg
Mixed-layer CIN: -4 J/kg
Mixed-layer LCL: 535 m above ground
0-6 km bulk shear: 54 kt
0-1 km storm-relative helicity: 364 m²/s²
0-3 km storm-relative helicity: 399 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
Oct 31, 6:56 AM CDT	Mesoscale Discussion	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 30 more	2 hr
Oct 31, 7:32 AM CDT	Tornado Watch	SPC	Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 19 more	6 hr
Oct 31, 10:37 AM CDT	Mesoscale Discussion	SPC	Acadia, Allen, Avoyelles, Calcasieu, Caldwell, Cameron and 20 more	83 min
Oct 31, 12:27 PM CDT	Tornado Watch	SPC	Ascension, Assumption, East Baton Rouge, East Feliciana, Iberville, Jefferson and 12 more	7 hr
Oct 31, 3:11 PM CDT	Mesoscale Discussion	SPC	Orleans, Saint Charles, Saint James, Saint John the Baptist, Saint Tammany, Tangipahoa and 1 more	94 min

Nearby

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