Alert archive / Arkansas / Mesoscale Discussions in 2009

Mesoscale Discussion 306

March 27, 200931 counties in Arkansas; 19 parishes in Louisiana

The Storm Prediction Center issued this mesoscale discussion at Mar 27, 2009, 10:24 PM CDT for 31 counties in Arkansas; 19 parishes in Louisiana. It was in force for 96 min.

The area

The outline as issued.

The facts

Issued: Mar 27, 2009, 10:24 PM CDT (03:24 UTC)
Expired: Mar 28, 2009, 12:00 AM CDT
In force: 96 min
Issued by: the Storm Prediction Center

All 50 counties

Arkansas County, AR, Ashley County, AR, Bradley County, AR, Calhoun County, AR, Chicot County, AR, Clark County, AR, Cleveland County, AR, Columbia County, AR, Dallas County, AR, Desha County, AR, Drew County, AR, Garland County, AR, Grant County, AR, Hempstead County, AR, Hot Spring County, AR, Howard County, AR, Jefferson County, AR, Lafayette County, AR, Lincoln County, AR, Lonoke County, AR, Miller County, AR, Monroe County, AR, Montgomery County, AR, Nevada County, AR, Ouachita County, AR, Pike County, AR, Polk County, AR, Prairie County, AR, Pulaski County, AR, Saline County, AR, Union County, AR, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Claiborne Parish, LA, De Soto Parish, LA, East Carroll Parish, LA, Jackson Parish, LA, Lincoln Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Red River Parish, LA, Richland Parish, LA, Sabine Parish, LA, Union Parish, LA, Webster Parish, LA, West Carroll Parish, LA, Winn Parish, LA

The radar

The Shreveport radar (KSHV), 172 km from the middle of the area, began a volume at 03:27 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

Shreveport, LA (KSHV), launched 00:00Z, 3.4 hours before the alert went out and 162 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: 920 J/kg
Mixed-layer CIN: -27 J/kg
Mixed-layer LCL: 522 m above ground
0-6 km bulk shear: 66 kt
0-1 km storm-relative helicity: 77 m²/s²
0-3 km storm-relative helicity: 322 m²/s²
Significant tornado parameter: 0.9
Supercell composite: 3.2

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
Mar 28, 5:22 AM CDT	Mesoscale Discussion	SPC	Arkansas, Baxter, Benton, Boone, Carroll, Cleburne and 20 more	53 min
Mar 27, 7:51 PM CDT	Tornado Watch	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Calcasieu and 36 more	9 hr
Mar 27, 8:21 PM CDT	Mesoscale Discussion	SPC	Orleans, Saint Bernard, Saint Tammany, Washington	84 min
Mar 27, 11:06 PM CDT	Mesoscale Discussion	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Caldwell and 32 more	84 min
Mar 27, 11:51 PM CDT	Mesoscale Discussion	SPC	Saint Bernard	84 min
Mar 28, 1:33 AM CDT	Mesoscale Discussion	SPC	Ascension, Assumption, East Baton Rouge, East Feliciana, Iberia, Iberville and 14 more	27 min
Mar 28, 4:25 AM CDT	Mesoscale Discussion	SPC	Saint Bernard, Saint Tammany	35 min

Nearby

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