Alert archive / Texas / Mesoscale Discussions in 2015

Mesoscale Discussion 604

May 11, 2015Sabine Parish, Louisiana; 13 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 11, 2015, 2:55 AM CDT for Sabine Parish, Louisiana; 13 counties in Texas. It was in force for 95 min.

The area

The outline as issued.

The facts

Issued: May 11, 2015, 2:55 AM CDT (07:55 UTC)
Expired: May 11, 2015, 4:30 AM CDT
In force: 95 min
Issued by: the Storm Prediction Center
Chance of a watch: 40%

Counties Sabine Parish, LA, Angelina County, TX, Brazos County, TX, Burleson County, TX, Houston County, TX, Leon County, TX, Madison County, TX, Nacogdoches County, TX, Robertson County, TX, Sabine County, TX, San Augustine County, TX, Shelby County, TX, Trinity County, TX, Walker County, TX

The radar

The Shreveport radar (KSHV), 156 km from the middle of the area, began a volume at 07:57 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 00:00Z, 7.9 hours before the alert went out and 164 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: 482 J/kg
Mixed-layer CIN: -35 J/kg
Mixed-layer LCL: 1448 m above ground
0-6 km bulk shear: 44 kt
0-1 km storm-relative helicity: 79 m²/s²
0-3 km storm-relative helicity: 72 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 5.7

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 10, 7:08 PM CDT	Mesoscale Discussion	SPC	Bossier, Caddo	97 min
May 10, 9:57 PM CDT	Mesoscale Discussion	SPC	Bossier, Caddo	93 min
May 10, 11:31 PM CDT	Tornado Watch	SPC	Bienville, Bossier, Caddo, Claiborne, De Soto, Lincoln and 3 more	5 hr
May 11, 12:30 PM CDT	Mesoscale Discussion	SPC	Ascension, Assumption, East Baton Rouge, East Feliciana, Iberia, Iberville and 18 more	2 hr
May 11, 1:44 PM CDT	Mesoscale Discussion	SPC	Ascension, East Baton Rouge, East Feliciana, Iberville, Livingston, Saint Helena and 3 more	2 hr
May 10, 7:34 PM CDT	Tornado Watch	SPC	Bowie, Camp, Cass, Cherokee, Franklin, Gregg and 9 more	4 hr
May 10, 8:06 PM CDT	Mesoscale Discussion	SPC	Anderson, Fannin, Freestone, Henderson, Hunt, Kaufman and 5 more	54 min
May 11, 2:31 AM CDT	Mesoscale Discussion	SPC	Edwards, Kerr, Kimble, Real, Sutton, Val Verde	89 min
May 11, 4:19 AM CDT	Severe Thunderstorm Watch	SPC	Bandera, Bastrop, Bexar, Blanco, Burnet, Caldwell and 18 more	7 hr
May 11, 7:04 AM CDT	Mesoscale Discussion	SPC	Austin, Bandera, Bastrop, Bexar, Blanco, Burleson and 34 more	56 min
May 11, 2:16 PM CDT	Mesoscale Discussion	SPC	Atascosa, Bee, Bexar, Colorado, DeWitt, Dimmit and 18 more	119 min

Nearby

Mesoscale Discussions in Texas, 2015 Mesoscale Discussions in Louisiana, 2015 Every mesoscale discussion in 2015

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.