Alert archive / Louisiana / Mesoscale Discussions in 2017

Mesoscale Discussion 1592

August 28, 201719 parishes in Louisiana; 4 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Aug 28, 2017, 11:37 AM CDT for 19 parishes in Louisiana; 4 counties in Texas. It was in force for 83 min.

The area

The outline as issued.

The facts

Issued: Aug 28, 2017, 11:37 AM CDT (16:37 UTC)
Expired: Aug 28, 2017, 1:00 PM CDT
In force: 83 min
Issued by: the Storm Prediction Center

All 23 counties

Acadia Parish, LA, Ascension Parish, LA, Assumption Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jefferson Davis Parish, LA, Jefferson Parish, LA, Lafayette Parish, LA, Lafourche Parish, LA, Orleans Parish, LA, Saint Charles Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Martin Parish, LA, St. Mary Parish, LA, Terrebonne Parish, LA, Vermilion Parish, LA, Chambers County, TX, Galveston County, TX, Jefferson County, TX, Orange County, TX

The radar

The Lake Charles radar (KLCH), 80 km from the middle of the area, began a volume at 16:37 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Tornado Watch 474Aug 28, 12:15 PM CDT

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 12:00Z, 4.6 hours before the alert went out and 78 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: 169 J/kg
Mixed-layer CIN: -37 J/kg
Mixed-layer LCL: 610 m above ground
0-6 km bulk shear: 50 kt
0-1 km storm-relative helicity: 377 m²/s²
0-3 km storm-relative helicity: 499 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.8

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
Aug 27, 9:50 PM CDT	Mesoscale Discussion	SPC	Acadia, Calcasieu, Cameron, Jefferson Davis, Vermilion	115 min
Aug 28, 1:51 AM CDT	Tornado Watch	SPC	Acadia, Calcasieu, Cameron, Iberia, Jefferson Davis, Vermilion	10 hr
Aug 28, 12:16 PM CDT	Tornado Watch	SPC	Acadia, Ascension, Assumption, Calcasieu, Cameron, East Baton Rouge and 20 more	12 hr
Aug 28, 3:58 PM CDT	Mesoscale Discussion	SPC	Acadia, Calcasieu, Cameron, Iberia, Jefferson Davis, Lafayette and 3 more	92 min
Aug 28, 6:49 PM CDT	Mesoscale Discussion	SPC	Acadia, Ascension, Assumption, Calcasieu, Cameron, Iberia and 16 more	116 min
Aug 27, 7:45 PM CDT	Mesoscale Discussion	SPC	Carson, Dallam, Hansford, Hartley, Hutchinson, Moore and 3 more	2 hr
Aug 28, 3:00 AM CDT	Mesoscale Discussion	SPC	Jefferson	60 min

Nearby

Mesoscale Discussions in Louisiana, 2017 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.