Alert archive / Louisiana / Mesoscale Discussions in 2017

Mesoscale Discussion 703

May 12, 201710 parishes in Louisiana

The Storm Prediction Center issued this mesoscale discussion at May 12, 2017, 4:24 AM CDT for 10 parishes in Louisiana. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued: May 12, 2017, 4:24 AM CDT (09:24 UTC)
Expired: May 12, 2017, 7:00 AM CDT
In force: 3 hr
Issued by: the Storm Prediction Center
Chance of a watch: 5%

Counties Acadia Parish, LA, Allen Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, Evangeline Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, Saint Landry Parish, LA, Vermilion Parish, LA

The radar

The Lake Charles radar (KLCH), 46 km from the middle of the area, began a volume at 09:27 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, 9.4 hours before the alert went out and 45 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: 9 J/kg
Mixed-layer CIN: -418 J/kg
Mixed-layer LCL: 1324 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: -12 m²/s²
0-3 km storm-relative helicity: 54 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
May 12, 9:56 AM CDT	Mesoscale Discussion	SPC	Ascension, Assumption, Jefferson, Lafourche, Livingston, Orleans and 8 more	3 hr
May 12, 10:35 AM CDT	Severe Thunderstorm Watch	SPC	Assumption, Jefferson, Lafourche, Orleans, Plaquemines, Saint Bernard and 5 more	5 hr
May 12, 10:59 AM CDT	Mesoscale Discussion	SPC	Morehouse, West Carroll	3 hr
May 12, 1:42 PM CDT	Mesoscale Discussion	SPC	Saint Bernard	108 min
May 12, 1:43 PM CDT	Mesoscale Discussion	SPC	Ascension, Assumption, East Baton Rouge, East Feliciana, Iberville, Livingston and 12 more	3 hr

Nearby

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.