Alert archive / Mississippi / Mesoscale Discussions in 2004

Mesoscale Discussion 499

April 29, 2004Chicot County, Arkansas; 10 parishes in Louisiana; 16 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 29, 2004, 5:36 PM CDT for Chicot County, Arkansas; 10 parishes in Louisiana; 16 counties in Mississippi. It was in force for 84 min.

The area

The outline as issued.

The facts

Issued: Apr 29, 2004, 5:36 PM CDT (22:36 UTC)
Expired: Apr 29, 2004, 7:00 PM CDT
In force: 84 min
Issued by: the Storm Prediction Center

All 27 counties

Chicot County, AR, Caldwell Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, East Carroll Parish, LA, Franklin Parish, LA, LaSalle Parish, LA, Madison Parish, LA, Richland Parish, LA, Tensas Parish, LA, West Carroll Parish, LA, Adams County, MS, Carroll County, MS, Claiborne County, MS, Grenada County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Jefferson County, MS, Leflore County, MS, Montgomery County, MS, Sharkey County, MS, Sunflower County, MS, Warren County, MS, Washington County, MS, Webster County, MS, Yazoo County, MS

The radar

The Jackson/Brandon,MS radar (KDGX), 118 km from the middle of the area, began a volume at 22:38 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.

The nearest sounding before it

Jackson, MS (KJAN), launched 12:00Z, 10.6 hours before the alert went out and 108 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: 1051 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 68 m²/s²
0-3 km storm-relative helicity: 169 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 29, 11:22 AM CDT	Mesoscale Discussion	SPC	Ashley, Bradley, Union	113 min
Apr 29, 1:10 PM CDT	Tornado Watch	SPC	Ashley, Bradley, Calhoun, Chicot, Drew, Union	6 hr
Apr 29, 2:44 PM CDT	Mesoscale Discussion	SPC	Ashley, Chicot, Drew	2 hr
Apr 29, 1:56 PM CDT	Mesoscale Discussion	SPC	Ascension, Assumption, Avoyelles, Concordia, East Baton Rouge, East Feliciana and 23 more	2 hr
Apr 29, 3:15 PM CDT	Tornado Watch	SPC	Plaquemines, Saint Bernard	6 hr
Apr 29, 6:15 PM CDT	Mesoscale Discussion	SPC	Orleans, Saint Bernard, Saint Tammany	90 min
Apr 29, 6:55 PM CDT	Tornado Watch	SPC	Attala, Carroll, Choctaw, Hinds, Holmes, Leake and 5 more	3 hr

Nearby

Mesoscale Discussions in Mississippi, 2004 Mesoscale Discussions in Louisiana, 2004 Mesoscale Discussions in Arkansas, 2004 Every mesoscale discussion in 2004

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.