Alert archive / Texas / Mesoscale Discussions in 2020

Mesoscale Discussion 501

April 29, 2020Calcasieu Parish, Cameron Parish, Louisiana; 31 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 29, 2020, 5:05 AM CDT for Calcasieu Parish, Cameron Parish, Louisiana; 31 counties in Texas. It was in force for 115 min.

The area

The outline as issued.

The facts

Issued: Apr 29, 2020, 5:05 AM CDT (10:05 UTC)
Expired: Apr 29, 2020, 7:00 AM CDT
In force: 115 min
Issued by: the Storm Prediction Center

All 33 counties

Calcasieu Parish, LA, Cameron Parish, LA, Austin County, TX, Bastrop County, TX, Blanco County, TX, Brazoria County, TX, Caldwell County, TX, Calhoun County, TX, Chambers County, TX, Colorado County, TX, Comal County, TX, DeWitt County, TX, Fayette County, TX, Fort Bend County, TX, Galveston County, TX, Goliad County, TX, Gonzales County, TX, Guadalupe County, TX, Harris County, TX, Hays County, TX, Jackson County, TX, Jefferson County, TX, Lavaca County, TX, Lee County, TX, Liberty County, TX, Matagorda County, TX, Orange County, TX, Travis County, TX, Victoria County, TX, Waller County, TX, Washington County, TX, Wharton County, TX, Williamson County, TX

The radar

The Houston radar (KHGX), 78 km from the middle of the area, began a volume at 10:07 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 00:00Z, 10.1 hours before the alert went out and 256 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: 24 J/kg
Mixed-layer CIN: -315 J/kg
Mixed-layer LCL: 1489 m above ground
0-6 km bulk shear: 38 kt
0-1 km storm-relative helicity: 19 m²/s²
0-3 km storm-relative helicity: 227 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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 28, 8:06 PM CDT	Mesoscale Discussion	SPC	Bossier, Caddo	54 min
Apr 28, 8:25 PM CDT	Severe Thunderstorm Watch	SPC	Bienville, Bossier, Caddo, Claiborne, De Soto, Red River and 2 more	9 hr
Apr 28, 11:57 PM CDT	Mesoscale Discussion	SPC	Caldwell, East Carroll, Franklin, Jackson, Madison, Morehouse and 5 more	63 min
Apr 29, 12:48 AM CDT	Severe Thunderstorm Watch	SPC	Caldwell, Catahoula, Concordia, East Carroll, Franklin, Grant and 12 more	4 hr
Apr 29, 1:56 AM CDT	Mesoscale Discussion	SPC	Allen, Avoyelles, Beauregard, Bienville, Caldwell, Catahoula and 19 more	2 hr
Apr 29, 2:40 AM CDT	Severe Thunderstorm Watch	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 23 more	6 hr
Apr 28, 9:04 PM CDT	Mesoscale Discussion	SPC	Jim Hogg, Starr, Zapata	116 min
Apr 28, 10:08 PM CDT	Mesoscale Discussion	SPC	Collin, Cooke, Dallas, Delta, Denton, Fannin and 11 more	97 min

Nearby

Mesoscale Discussions in Texas, 2020 Mesoscale Discussions in Louisiana, 2020 Every mesoscale discussion in 2020

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.