Alert archive / Texas / Mesoscale Discussions in 2014

Mesoscale Discussion 539

May 9, 20149 counties in Arkansas; 9 parishes in Louisiana; 20 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 9, 2014, 3:18 PM CDT for 9 counties in Arkansas; 9 parishes in Louisiana; 20 counties in Texas. It was in force for 117 min.

The area

The outline as issued.

The facts

Issued: May 9, 2014, 3:18 PM CDT (20:18 UTC)
Expired: May 9, 2014, 5:15 PM CDT
In force: 117 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

All 38 counties

Columbia County, AR, Hempstead County, AR, Howard County, AR, Lafayette County, AR, Little River County, AR, Miller County, AR, Nevada County, AR, Ouachita County, AR, Sevier County, AR, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Claiborne Parish, LA, De Soto Parish, LA, Natchitoches Parish, LA, Red River Parish, LA, Sabine Parish, LA, Webster Parish, LA, Angelina County, TX, Bowie County, TX, Camp County, TX, Cass County, TX, Cherokee County, TX, Franklin County, TX, Gregg County, TX, Harrison County, TX, Marion County, TX, Morris County, TX, Nacogdoches County, TX, Panola County, TX, Red River County, TX, Rusk County, TX, Sabine County, TX, San Augustine County, TX, Shelby County, TX, Smith County, TX, Titus County, TX, Upshur County, TX

The radar

The Shreveport radar (KSHV), 54 km from the middle of the area, began a volume at 20:19 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 (KBAD), launched 12:00Z, 8.3 hours before the alert went out and 61 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: 601 J/kg
Mixed-layer CIN: -82 J/kg
Mixed-layer LCL: 511 m above ground
0-6 km bulk shear: 38 kt
0-1 km storm-relative helicity: 316 m²/s²
0-3 km storm-relative helicity: 378 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 7.1

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 9, 2:35 PM CDT	Mesoscale Discussion	SPC	Clay	115 min
May 9, 6:14 PM CDT	Mesoscale Discussion	SPC	Columbia, Hempstead, Lafayette, Miller	61 min
May 9, 6:25 PM CDT	Mesoscale Discussion	SPC	Clay, Craighead, Greene	65 min
May 8, 8:20 PM CDT	Mesoscale Discussion	SPC	Bell, Blanco, Burnet, Comal, Falls, Gillespie and 8 more	55 min
May 8, 9:41 PM CDT	Mesoscale Discussion	SPC	Bell, Blanco, Burnet, Falls, Gillespie, Hays and 5 more	64 min
May 9, 9:46 AM CDT	Mesoscale Discussion	SPC	Bandera, Kerr, Kinney, Maverick, Medina, Real and 2 more	2 hr
May 9, 10:39 AM CDT	Severe Thunderstorm Watch	SPC	Atascosa, Bandera, Bastrop, Bexar, Blanco, Burnet and 26 more	6 hr
May 9, 2:00 PM CDT	Mesoscale Discussion	SPC	Anderson, Atascosa, Austin, Bandera, Bastrop, Bell and 45 more	90 min
May 9, 4:34 PM CDT	Mesoscale Discussion	SPC	Bee, Brooks, Duval, Jim Hogg, Jim Wells, Kleberg and 6 more	116 min
May 9, 4:55 PM CDT	Severe Thunderstorm Watch	SPC	Brooks, Cameron, Duval, Hidalgo, Jim Hogg, Jim Wells and 7 more	6 hr

Nearby

Mesoscale Discussions in Texas, 2014 Mesoscale Discussions in Arkansas, 2014 Mesoscale Discussions in Louisiana, 2014 Every mesoscale discussion in 2014

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.