Alert archive / Texas / Mesoscale Discussions in 2015

Mesoscale Discussion 418

April 22, 201521 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 22, 2015, 1:43 PM CDT for 21 counties in Texas. It was in force for 92 min.

The area

The outline as issued.

The facts

Issued: Apr 22, 2015, 1:43 PM CDT (18:43 UTC)
Expired: Apr 22, 2015, 3:15 PM CDT
In force: 92 min
Issued by: the Storm Prediction Center
Chance of a watch: 40%

All 21 counties

Atascosa County, TX, Austin County, TX, Bandera County, TX, Bastrop County, TX, Bexar County, TX, Caldwell County, TX, Colorado County, TX, Comal County, TX, DeWitt County, TX, Fayette County, TX, Frio County, TX, Gonzales County, TX, Guadalupe County, TX, Hays County, TX, Kendall County, TX, Lavaca County, TX, Lee County, TX, Medina County, TX, Travis County, TX, Washington County, TX, Wilson County, TX

The radar

The Austin/San Antonio radar (KEWX), 44 km from the middle of the area, began a volume at 18:46 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

Corpus Christi, TX (KCRP), launched 12:00Z, 6.7 hours before the alert went out and 198 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: 856 J/kg
Mixed-layer CIN: -173 J/kg
Mixed-layer LCL: 763 m above ground
0-6 km bulk shear: 55 kt
0-1 km storm-relative helicity: 159 m²/s²
0-3 km storm-relative helicity: 202 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.9

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 22, 2:55 AM CDT	Mesoscale Discussion	SPC	Hemphill, Wheeler	3 hr
Apr 22, 10:43 AM CDT	Mesoscale Discussion	SPC	Aransas, Atascosa, Austin, Bandera, Bastrop, Bee and 36 more	2 hr
Apr 22, 11:13 AM CDT	Tornado Watch	SPC	Aransas, Bee, Calhoun, Duval, Goliad, Jim Wells and 7 more	7 hr
Apr 22, 12:07 PM CDT	Mesoscale Discussion	SPC	Jim Wells, Nueces	83 min
Apr 22, 2:07 PM CDT	Mesoscale Discussion	SPC	Archer, Armstrong, Baylor, Briscoe, Castro, Childress and 25 more	2 hr
Apr 22, 2:29 PM CDT	Mesoscale Discussion	SPC	Aransas, Bee, Calhoun, Duval, Goliad, Jim Wells and 5 more	61 min
Apr 22, 2:56 PM CDT	Tornado Watch	SPC	Archer, Armstrong, Bailey, Baylor, Briscoe, Callahan and 36 more	9 hr
Apr 22, 5:48 PM CDT	Mesoscale Discussion	SPC	Bosque, Comanche, Coryell, Ellis, Erath, Hamilton and 8 more	117 min
Apr 22, 6:45 PM CDT	Mesoscale Discussion	SPC	Archer, Armstrong, Baylor, Briscoe, Carson, Castro and 29 more	2 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.