Alert archive / Texas / Mesoscale Discussions in 2017

Mesoscale Discussion 1566

August 25, 2017Cameron Parish, Vermilion Parish, Louisiana; 18 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Aug 25, 2017, 3:46 PM CDT for Cameron Parish, Vermilion Parish, Louisiana; 18 counties in Texas. It was in force for 59 min.

The area

The outline as issued.

The facts

Issued: Aug 25, 2017, 3:46 PM CDT (20:46 UTC)
Expired: Aug 25, 2017, 4:45 PM CDT
In force: 59 min
Issued by: the Storm Prediction Center
Chance of a watch: 5%

Counties Cameron Parish, LA, Vermilion Parish, LA, Aransas County, TX, Brazoria County, TX, Calhoun County, TX, Chambers County, TX, Colorado County, TX, Fort Bend County, TX, Galveston County, TX, Goliad County, TX, Harris County, TX, Jackson County, TX, Jefferson County, TX, Liberty County, TX, Matagorda County, TX, Orange County, TX, Refugio County, TX, Victoria County, TX, Waller County, TX, Wharton County, TX

The radar

The Houston radar (KHGX), 66 km from the middle of the area, began a volume at 20:45 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, 8.8 hours before the alert went out and 176 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: 1337 J/kg
Mixed-layer CIN: -25 J/kg
Mixed-layer LCL: 748 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: 102 m²/s²
0-3 km storm-relative helicity: 124 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
Aug 25, 10:19 AM CDT	Mesoscale Discussion	SPC	Calcasieu, Cameron	3 hr
Aug 25, 2:02 PM CDT	Tornado Watch	SPC	Cameron, Vermilion	12 hr

Nearby

Mesoscale Discussions in Texas, 2017 Mesoscale Discussions in Louisiana, 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.