Alert archive / Texas / Mesoscale Discussions in 2015

Mesoscale Discussion 450

April 25, 201517 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 25, 2015, 6:52 AM CDT for 17 counties in Texas. It was in force for 83 min.

The area

The outline as issued.

The facts

Issued: Apr 25, 2015, 6:52 AM CDT (11:52 UTC)
Expired: Apr 25, 2015, 8:15 AM CDT
In force: 83 min
Issued by: the Storm Prediction Center

Counties Atascosa County, TX, Brazoria County, TX, Chambers County, TX, DeWitt County, TX, Fort Bend County, TX, Frio County, TX, Goliad County, TX, Harris County, TX, Jackson County, TX, Jefferson County, TX, Karnes County, TX, Lavaca County, TX, Liberty County, TX, Matagorda County, TX, Victoria County, TX, Wharton County, TX, Wilson County, TX

The radar

The Austin/San Antonio radar (KEWX), 115 km from the middle of the area, began a volume at 11:53 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 109Apr 25, 7:15 AM CDT

The nearest sounding before it

Corpus Christi, TX (KCRP), launched 00:00Z, 11.9 hours before the alert went out and 195 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: 2964 J/kg
Mixed-layer CIN: -221 J/kg
Mixed-layer LCL: 666 m above ground
0-6 km bulk shear: 48 kt
0-1 km storm-relative helicity: 96 m²/s²
0-3 km storm-relative helicity: 88 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 3.1

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
Apr 24, 7:46 PM CDT	Mesoscale Discussion	SPC	Anderson, Bosque, Bowie, Camp, Cass, Cherokee and 38 more	89 min
Apr 24, 9:20 PM CDT	Mesoscale Discussion	SPC	Harrison, Panola	55 min
Apr 24, 9:59 PM CDT	Tornado Watch	SPC	Cherokee, Gregg, Harrison, Marion, Nacogdoches, Panola and 3 more	4 hr
Apr 24, 10:55 PM CDT	Mesoscale Discussion	SPC	Cameron	65 min
Apr 25, 2:48 AM CDT	Mesoscale Discussion	SPC	Atascosa, Bandera, Bexar, Caldwell, Comal, DeWitt and 17 more	87 min
Apr 25, 3:09 AM CDT	Severe Thunderstorm Watch	SPC	Atascosa, Austin, Bandera, Bastrop, Bexar, Blanco and 31 more	7 hr
Apr 25, 4:31 AM CDT	Mesoscale Discussion	SPC	Atascosa, Austin, Bandera, Bastrop, Bexar, Caldwell and 23 more	89 min
Apr 25, 7:12 AM CDT	Severe Thunderstorm Watch	SPC	Brazoria, Chambers, Fort Bend, Galveston, Hardin, Harris and 8 more	6 hr

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.