Alert archive / Texas / Mesoscale Discussions in 2017

Mesoscale Discussion 800

May 20, 201719 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 20, 2017, 12:56 PM CDT for 19 counties in Texas. It was in force for 94 min.

The area

The outline as issued.

The facts

Issued: May 20, 2017, 12:56 PM CDT (17:56 UTC)
Expired: May 20, 2017, 2:30 PM CDT
In force: 94 min
Issued by: the Storm Prediction Center

Counties Atascosa County, TX, Bee County, TX, Bexar County, TX, DeWitt County, TX, Dimmit County, TX, Frio County, TX, Goliad County, TX, Gonzales County, TX, Guadalupe County, TX, Karnes County, TX, Kinney County, TX, La Salle County, TX, Live Oak County, TX, Maverick County, TX, McMullen County, TX, Medina County, TX, Uvalde County, TX, Wilson County, TX, Zavala County, TX

The radar

The Laughlin AFB radar (KDFX), 145 km from the middle of the area, began a volume at 17:58 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, 5.9 hours before the alert went out and 190 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: 2452 J/kg
Mixed-layer CIN: -31 J/kg
Mixed-layer LCL: 634 m above ground
0-6 km bulk shear: 44 kt
0-1 km storm-relative helicity: 88 m²/s²
0-3 km storm-relative helicity: 153 m²/s²
Significant tornado parameter: 1.7
Supercell composite: 8.8

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 19, 7:15 PM CDT	Mesoscale Discussion	SPC	Brown, Callahan, Coke, Coleman, Concho, Fisher and 11 more	60 min
May 19, 7:44 PM CDT	Tornado Watch	SPC	Brown, Callahan, Coke, Coleman, Concho, Fisher and 15 more	7 hr
May 19, 11:05 PM CDT	Mesoscale Discussion	SPC	Brown, Callahan, Coke, Coleman, Comanche, Concho and 14 more	115 min
May 20, 7:41 AM CDT	Mesoscale Discussion	SPC	Aransas, Atascosa, Bandera, Bee, Bexar, Caldwell and 21 more	94 min
May 20, 10:15 AM CDT	Severe Thunderstorm Watch	SPC	Atascosa, Bee, Bexar, DeWitt, Dimmit, Duval and 18 more	11 hr
May 20, 3:46 PM CDT	Mesoscale Discussion	SPC	Atascosa, Bee, Bexar, DeWitt, Dimmit, Duval and 19 more	59 min

Nearby

Mesoscale Discussions in Texas, 2017 Every mesoscale discussion in 2017

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.