Alert archive / Louisiana / Mesoscale Discussions in 2009

Mesoscale Discussion 11

January 4, 2009Ashley County, Chicot County, Arkansas; 14 parishes in Louisiana; 12 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Jan 4, 2009, 2:07 PM CST for Ashley County, Chicot County, Arkansas; 14 parishes in Louisiana; 12 counties in Mississippi. It was in force for 113 min.

The area

The outline as issued.

The facts

Issued: Jan 4, 2009, 2:07 PM CST (20:07 UTC)
Expired: Jan 4, 2009, 4:00 PM CST
In force: 113 min
Issued by: the Storm Prediction Center

All 28 counties

Ashley County, AR, Chicot County, AR, Caldwell Parish, LA, East Carroll Parish, LA, Franklin Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Richland Parish, LA, Tensas Parish, LA, Union Parish, LA, West Carroll Parish, LA, Winn Parish, LA, Carroll County, MS, Claiborne County, MS, Hinds County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Leflore County, MS, Sharkey County, MS, Sunflower County, MS, Warren County, MS, Washington County, MS, Yazoo County, MS

The radar

The Jackson/Brandon,MS radar (KDGX), 141 km from the middle of the area, began a volume at 20:10 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 12:00Z, 8.1 hours before the alert went out and 131 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: 333 J/kg
Mixed-layer CIN: -34 J/kg
Mixed-layer LCL: 467 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 181 m²/s²
0-3 km storm-relative helicity: 159 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
Jan 3, 6:29 PM CST	Mesoscale Discussion	SPC	Ascension, Assumption, Avoyelles, Caldwell, Catahoula, Concordia and 23 more	61 min

Nearby

Mesoscale Discussions in Louisiana, 2009 Mesoscale Discussions in Mississippi, 2009 Mesoscale Discussions in Arkansas, 2009 Every mesoscale discussion in 2009

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.