Alert archive / Texas / Mesoscale Discussions in 2016

Mesoscale Discussion 431

April 21, 20165 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 21, 2016, 9:40 AM CDT for 5 counties in Texas. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Apr 21, 2016, 9:40 AM CDT (14:40 UTC)
Expired: Apr 21, 2016, 11:45 AM CDT
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 5%

Counties Brazoria County, TX, Chambers County, TX, Hardin County, TX, Liberty County, TX, Tyler County, TX

The radar

The Houston radar (KHGX), 20 km from the middle of the area, began a volume at 14:43 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 12:00Z, 2.7 hours before the alert went out and 191 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: 574 J/kg
Mixed-layer CIN: -35 J/kg
Mixed-layer LCL: 655 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 86 m²/s²
0-3 km storm-relative helicity: 32 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.7

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
Apr 20, 8:17 PM CDT	Severe Thunderstorm Watch	SPC	Armstrong, Baylor, Briscoe, Carson, Childress, Collingsworth and 23 more	6 hr
Apr 20, 8:22 PM CDT	Mesoscale Discussion	SPC	Duval, Jim Hogg, Starr, Webb, Zapata	83 min
Apr 20, 9:40 PM CDT	Mesoscale Discussion	SPC	Cottle, Crosby, Dickens, Fisher, Foard, Garza and 7 more	65 min
Apr 20, 11:35 PM CDT	Mesoscale Discussion	SPC	Crosby, Fisher, Garza, Haskell, Jones, Kent and 5 more	55 min
Apr 21, 1:16 AM CDT	Mesoscale Discussion	SPC	Borden, Callahan, Coke, Coleman, Dawson, Fisher and 19 more	89 min
Apr 21, 1:44 AM CDT	Severe Thunderstorm Watch	SPC	Borden, Coke, Dawson, Gaines, Glasscock, Howard and 7 more	4 hr
Apr 21, 4:57 AM CDT	Mesoscale Discussion	SPC	Coke, Coleman, Concho, Runnels, Taylor, Tom Green	93 min
Apr 21, 2:14 PM CDT	Mesoscale Discussion	SPC	Cameron, Hidalgo, Kenedy, Willacy	2 hr
Apr 21, 2:36 PM CDT	Mesoscale Discussion	SPC	Brewster, Crockett, Edwards, Pecos, Terrell, Val Verde	2 hr

Nearby

Mesoscale Discussions in Texas, 2016 Every mesoscale discussion in 2016

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.