Alert archive / Texas / Mesoscale Discussions in 2015

Mesoscale Discussion 799

May 27, 201510 parishes in Louisiana; 19 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 27, 2015, 4:48 AM CDT for 10 parishes in Louisiana; 19 counties in Texas. It was in force for 117 min.

The area

The outline as issued.

The facts

Issued: May 27, 2015, 4:48 AM CDT (09:48 UTC)
Expired: May 27, 2015, 6:45 AM CDT
In force: 117 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

All 29 counties

Allen Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Grant Parish, LA, Natchitoches Parish, LA, Rapides Parish, LA, Red River Parish, LA, Sabine Parish, LA, Vernon Parish, LA, Winn Parish, LA, Austin County, TX, Chambers County, TX, Fort Bend County, TX, Hardin County, TX, Harris County, TX, Jasper County, TX, Jefferson County, TX, Liberty County, TX, Montgomery County, TX, Newton County, TX, Orange County, TX, Polk County, TX, Sabine County, TX, San Augustine County, TX, San Jacinto County, TX, Tyler County, TX, Waller County, TX, Washington County, TX, Wharton County, TX

The radar

The Houston radar (KHGX), 129 km from the middle of the area, began a volume at 09:51 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

Lake Charles Mun, LA (KLCH), launched 00:00Z, 9.8 hours before the alert went out and 151 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: 1199 J/kg
Mixed-layer CIN: -63 J/kg
Mixed-layer LCL: 1356 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 67 m²/s²
0-3 km storm-relative helicity: 126 m²/s²
Significant tornado parameter: 0.4
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 26, 8:25 PM CDT	Mesoscale Discussion	SPC	Coke, Coleman, Concho, Irion, Kimble, McCulloch and 6 more	95 min
May 26, 8:51 PM CDT	Mesoscale Discussion	SPC	Callahan, Comanche, Eastland, Erath, Hood, Jack and 8 more	84 min
May 26, 9:27 PM CDT	Severe Thunderstorm Watch	SPC	Bosque, Brown, Callahan, Coleman, Collin, Comanche and 37 more	6 hr
May 26, 11:47 PM CDT	Mesoscale Discussion	SPC	Anderson, Bell, Bosque, Comanche, Coryell, Erath and 16 more	88 min
May 27, 11:39 AM CDT	Mesoscale Discussion	SPC	Atascosa, Bandera, Bexar, Blanco, Caldwell, Comal and 16 more	66 min
May 27, 2:13 PM CDT	Mesoscale Discussion	SPC	Childress, Collingsworth, Donley, Gray, Hemphill, Lipscomb and 3 more	92 min
May 27, 2:46 PM CDT	Tornado Watch	SPC	Armstrong, Carson, Collingsworth, Donley, Gray, Hansford and 7 more	10 hr
May 27, 3:09 PM CDT	Mesoscale Discussion	SPC	Archer, Baylor, Brown, Callahan, Clay, Coleman and 18 more	2 hr
May 27, 5:05 PM CDT	Mesoscale Discussion	SPC	Andrews, Bailey, Borden, Briscoe, Castro, Cochran and 23 more	115 min
May 27, 6:16 PM CDT	Mesoscale Discussion	SPC	Collingsworth, Donley, Gray, Hansford, Hemphill, Lipscomb and 3 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.