Alert archive / Louisiana / Mesoscale Discussions in 2009

Mesoscale Discussion 94

February 11, 20099 counties in Arkansas; 19 parishes in Louisiana; Washington County, Mississippi

The Storm Prediction Center issued this mesoscale discussion at Feb 11, 2009, 12:37 AM CST for 9 counties in Arkansas; 19 parishes in Louisiana; Washington County, Mississippi. It was in force for 53 min.

The area

The outline as issued.

The facts

Issued: Feb 11, 2009, 12:37 AM CST (06:37 UTC)
Expired: Feb 11, 2009, 1:30 AM CST
In force: 53 min
Issued by: the Storm Prediction Center

All 29 counties

Ashley County, AR, Bradley County, AR, Calhoun County, AR, Chicot County, AR, Cleveland County, AR, Desha County, AR, Drew County, AR, Lincoln County, AR, Union County, AR, Bienville Parish, LA, Caldwell Parish, LA, Catahoula Parish, LA, Claiborne Parish, LA, East Carroll Parish, LA, Franklin Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Rapides Parish, LA, Richland Parish, LA, Union Parish, LA, Vernon Parish, LA, West Carroll Parish, LA, Winn Parish, LA, Washington County, MS

The radar

The Shreveport radar (KSHV), 139 km from the middle of the area, began a volume at 06:40 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 15Feb 11, 1:05 AM CST

The nearest sounding before it

Shreveport, LA (KSHV), launched 00:00Z, 6.6 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: 367 J/kg
Mixed-layer CIN: -98 J/kg
Mixed-layer LCL: 785 m above ground
0-6 km bulk shear: 64 kt
0-1 km storm-relative helicity: 410 m²/s²
0-3 km storm-relative helicity: 547 m²/s²
Significant tornado parameter: 0.7
Supercell composite: 10.5

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
Feb 10, 6:13 PM CST	Mesoscale Discussion	SPC	Crawford, Washington	92 min
Feb 10, 8:34 PM CST	Mesoscale Discussion	SPC	Conway, Crawford, Faulkner, Franklin, Garland, Hempstead and 19 more	86 min
Feb 10, 9:30 PM CST	Tornado Watch	SPC	Baxter, Benton, Boone, Carroll, Clark, Cleburne and 42 more	7 hr
Feb 10, 11:13 PM CST	Mesoscale Discussion	SPC	Baxter, Boone, Cleburne, Conway, Faulkner, Fulton and 18 more	92 min
Feb 10, 11:45 PM CST	Tornado Watch	SPC	Arkansas, Clay, Craighead, Crittenden, Cross, Greene and 12 more	6 hr
Feb 11, 1:04 AM CST	Tornado Watch	SPC	Ashley, Bradley, Calhoun, Chicot, Cleveland, Desha and 3 more	5 hr
Feb 11, 2:30 AM CST	Mesoscale Discussion	SPC	Arkansas, Clay, Craighead, Crittenden, Cross, Fulton and 18 more	90 min
Feb 11, 4:01 AM CST	Mesoscale Discussion	SPC	Ashley, Bradley, Calhoun, Chicot, Cleveland, Columbia and 6 more	89 min
Feb 11, 5:26 AM CST	Mesoscale Discussion	SPC	Mississippi	64 min
Feb 11, 9:36 AM CST	Mesoscale Discussion	SPC	George, Greene, Harrison, Jackson	84 min

Nearby

Mesoscale Discussions in Louisiana, 2009 Mesoscale Discussions in Arkansas, 2009 Mesoscale Discussions in Mississippi, 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.