Alert archive / Mississippi / Mesoscale Discussions in 2014

Mesoscale Discussion 475

April 29, 201413 parishes in Louisiana; 47 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 29, 2014, 12:02 PM CDT for 13 parishes in Louisiana; 47 counties in Mississippi. It was in force for 88 min.

The area

The outline as issued.

The facts

Issued: Apr 29, 2014, 12:02 PM CDT (17:02 UTC)
Expired: Apr 29, 2014, 1:30 PM CDT
In force: 88 min
Issued by: the Storm Prediction Center
Chance of a watch: 95%

All 60 counties

Catahoula Parish, LA, Concordia Parish, LA, East Baton Rouge Parish, LA, East Carroll Parish, LA, East Feliciana Parish, LA, Franklin Parish, LA, Madison Parish, LA, Pointe Coupee Parish, LA, Saint Helena Parish, LA, Tangipahoa Parish, LA, Tensas Parish, LA, Washington Parish, LA, West Feliciana Parish, LA, Adams County, MS, Amite County, MS, Attala County, MS, Carroll County, MS, Choctaw County, MS, Claiborne County, MS, Clay County, MS, Copiah County, MS, Covington County, MS, Forrest County, MS, Franklin County, MS, Grenada County, MS, Hinds County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Jasper County, MS, Jefferson County, MS, Jefferson Davis County, MS, Jones County, MS, Kemper County, MS, Lamar County, MS, Lauderdale County, MS, Lawrence County, MS, Leake County, MS, Leflore County, MS, Lincoln County, MS, Madison County, MS, Marion County, MS, Montgomery County, MS, Neshoba County, MS, Newton County, MS, Noxubee County, MS, Oktibbeha County, MS, Pearl River County, MS, Pike County, MS, Rankin County, MS, Scott County, MS, Sharkey County, MS, Simpson County, MS, Smith County, MS, Walthall County, MS, Warren County, MS, Webster County, MS, Wilkinson County, MS, Winston County, MS, Yazoo County, MS

The radar

The Jackson/Brandon,MS radar (KDGX), 19 km from the middle of the area, began a volume at 17:03 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 116Apr 29, 12:45 PM CDT

The nearest sounding before it

Jackson, MS (KJAN), launched 12:00Z, 5.0 hours before the alert went out and 18 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 2070 m above ground
0-6 km bulk shear: 70 kt
0-1 km storm-relative helicity: 42 m²/s²
0-3 km storm-relative helicity: 34 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
Apr 28, 7:59 PM CDT	Tornado Watch	SPC	Concordia, East Feliciana, Saint Helena, Tangipahoa, Washington, West Feliciana	11 hr
Apr 29, 12:46 PM CDT	Tornado Watch	SPC	Ascension, Catahoula, Concordia, East Baton Rouge, East Carroll, East Feliciana and 14 more	10 hr
Apr 29, 6:01 PM CDT	Mesoscale Discussion	SPC	Tangipahoa, Washington	89 min
Apr 28, 7:12 PM CDT	Mesoscale Discussion	SPC	Attala, Choctaw, Clay, Copiah, Hinds, Itawamba and 14 more	93 min
Apr 28, 9:34 PM CDT	Mesoscale Discussion	SPC	Amite, Clarke, Covington, Forrest, Greene, Jasper and 14 more	86 min
Apr 28, 11:20 PM CDT	Mesoscale Discussion	SPC	Clarke, Forrest, Greene, Jones, Lamar, Perry and 2 more	85 min
Apr 29, 3:27 PM CDT	Mesoscale Discussion	SPC	Itawamba, Monroe	33 min

Nearby

Mesoscale Discussions in Mississippi, 2014 Mesoscale Discussions in Louisiana, 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.