Alert archive / Texas / Mesoscale Discussions in 2015

Mesoscale Discussion 358

April 18, 201517 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 18, 2015, 4:32 PM CDT for 17 counties in Texas. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Apr 18, 2015, 4:32 PM CDT (21:32 UTC)
Expired: Apr 18, 2015, 7:00 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 40%

Counties Atascosa County, TX, Bastrop County, TX, Bexar County, TX, Caldwell County, TX, Comal County, TX, Dimmit County, TX, Frio County, TX, Guadalupe County, TX, Hays County, TX, Karnes County, TX, La Salle County, TX, Maverick County, TX, McMullen County, TX, Travis County, TX, Williamson County, TX, Wilson County, TX, Zavala County, TX

The radar

The Austin/San Antonio radar (KEWX), 102 km from the middle of the area, began a volume at 21:33 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

Del Rio, TX (KDLF), launched 12:00Z, 9.5 hours before the alert went out and 188 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: 668 J/kg
Mixed-layer CIN: -134 J/kg
Mixed-layer LCL: 705 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: -48 m²/s²
0-3 km storm-relative helicity: 81 m²/s²
Significant tornado parameter: -0.0
Supercell composite: -0.4

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
Apr 17, 7:26 PM CDT	Mesoscale Discussion	SPC	Carson, Hansford, Hutchinson, Ochiltree, Roberts	2 hr
Apr 17, 7:39 PM CDT	Mesoscale Discussion	SPC	Chambers, Galveston, Jefferson	96 min
Apr 17, 9:10 PM CDT	Mesoscale Discussion	SPC	Aransas, Brooks, Calhoun, Duval, Hidalgo, Jim Hogg and 7 more	95 min
Apr 17, 9:13 PM CDT	Severe Thunderstorm Watch	SPC	Brazoria, Chambers, Fort Bend, Galveston, Hardin, Harris and 4 more	5 hr
Apr 17, 10:59 PM CDT	Mesoscale Discussion	SPC	Aransas, Brooks, Hidalgo, Kenedy, Kleberg, Nueces	91 min
Apr 17, 11:31 PM CDT	Mesoscale Discussion	SPC	Chambers, Galveston, Jefferson, Orange	59 min
Apr 18, 1:52 PM CDT	Mesoscale Discussion	SPC	Archer, Baylor, Brown, Callahan, Clay, Coleman and 23 more	113 min
Apr 18, 2:13 PM CDT	Severe Thunderstorm Watch	SPC	Bandera, Bastrop, Bexar, Blanco, Bosque, Brown and 58 more	8 hr
Apr 18, 2:27 PM CDT	Tornado Watch	SPC	Archer, Baylor, Childress, Clay, Collingsworth, Cottle and 9 more	6 hr
Apr 18, 4:48 PM CDT	Mesoscale Discussion	SPC	Hidalgo, Kenedy, Kleberg, Willacy	2 hr
Apr 18, 5:23 PM CDT	Mesoscale Discussion	SPC	Collin, Dallas, Ellis, Falls, Hill, Kaufman and 6 more	3 hr
Apr 18, 5:46 PM CDT	Severe Thunderstorm Watch	SPC	Anderson, Bell, Collin, Cooke, Dallas, Denton and 20 more	5 hr
Apr 18, 6:03 PM CDT	Mesoscale Discussion	SPC	Baylor, Childress, Collingsworth, Cottle, Foard, Hardeman and 3 more	87 min
Apr 18, 6:40 PM CDT	Mesoscale Discussion	SPC	Bandera, Bell, Blanco, Bosque, Brown, Burnet and 48 more	95 min

Nearby

Mesoscale Discussions in Texas, 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.