Alert archive / Louisiana / Mesoscale Discussions in 2009

Mesoscale Discussion 826

May 14, 20094 counties in Arkansas; 10 parishes in Louisiana; 8 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 14, 2009, 5:26 AM CDT for 4 counties in Arkansas; 10 parishes in Louisiana; 8 counties in Texas. It was in force for 64 min.

The area

The outline as issued.

The facts

Issued: May 14, 2009, 5:26 AM CDT (10:26 UTC)
Expired: May 14, 2009, 6:30 AM CDT
In force: 64 min
Issued by: the Storm Prediction Center

All 22 counties

Columbia County, AR, Lafayette County, AR, Miller County, AR, Union County, AR, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Claiborne Parish, LA, De Soto Parish, LA, Jackson Parish, LA, Lincoln Parish, LA, Red River Parish, LA, Union Parish, LA, Webster Parish, LA, Cass County, TX, Gregg County, TX, Harrison County, TX, Marion County, TX, Panola County, TX, Rusk County, TX, Smith County, TX, Upshur County, TX

The radar

The Shreveport radar (KSHV), 22 km from the middle of the area, began a volume at 10:26 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, 10.4 hours before the alert went out and 24 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: 1900 J/kg
Mixed-layer CIN: -7 J/kg
Mixed-layer LCL: 1477 m above ground
0-6 km bulk shear: 28 kt
0-1 km storm-relative helicity: 50 m²/s²
0-3 km storm-relative helicity: 146 m²/s²
Significant tornado parameter: 0.5
Supercell composite: 6.4

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
May 13, 8:22 PM CDT	Mesoscale Discussion	SPC	Benton, Boone, Carroll, Crawford, Franklin, Madison and 2 more	53 min
May 13, 9:36 PM CDT	Severe Thunderstorm Watch	SPC	Baxter, Benton, Boone, Carroll, Crawford, Franklin and 11 more	6 hr
May 13, 11:27 PM CDT	Mesoscale Discussion	SPC	Baxter, Benton, Boone, Carroll, Clark, Clay and 44 more	93 min
May 14, 1:01 AM CDT	Severe Thunderstorm Watch	SPC	Arkansas, Clark, Clay, Craighead, Crittenden, Cross and 23 more	5 hr
May 14, 1:11 AM CDT	Severe Thunderstorm Watch	SPC	Columbia, Hempstead, Howard, Lafayette, Little River, Miller and 2 more	6 hr
May 14, 3:56 AM CDT	Mesoscale Discussion	SPC	Crittenden, Cross, Lee, Mississippi, St. Francis, Woodruff	64 min

Nearby

Mesoscale Discussions in Louisiana, 2009 Mesoscale Discussions in Texas, 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.