Alert archive / Louisiana / Mesoscale Discussions in 2025

Mesoscale Discussion 47

January 21, 202514 parishes in Louisiana; Orange County, Texas

The Storm Prediction Center issued this mesoscale discussion at Jan 21, 2025, 4:47 AM CST for 14 parishes in Louisiana; Orange County, Texas. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued: Jan 21, 2025, 4:47 AM CST (10:47 UTC)
Expired: Jan 21, 2025, 9:15 AM CST
In force: 4 hr
Issued by: the Storm Prediction Center
Concerning: Heavy snow

Counties Acadia Parish, LA, Allen Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, Evangeline Parish, LA, Iberville Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, Pointe Coupee Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, Vermilion Parish, LA, West Baton Rouge Parish, LA, Orange County, TX

The radar

The Lake Charles radar (KLCH), 55 km from the middle of the area, began a volume at 10:49 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, 10.8 hours before the alert went out and 54 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1858 m above ground
0-6 km bulk shear: 80 kt
0-1 km storm-relative helicity: -30 m²/s²
0-3 km storm-relative helicity: 245 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
Jan 21, 8:46 AM CST	Mesoscale Discussion	SPC	Ascension, Assumption, East Baton Rouge, East Feliciana, Iberia, Iberville and 19 more	4 hr
Jan 21, 4:52 PM CST	Mesoscale Discussion	SPC	Saint Bernard	6 hr
Jan 20, 10:00 PM CST	Mesoscale Discussion	SPC	Austin, Bastrop, Bee, Brazos, Burleson, Caldwell and 29 more	4 hr
Jan 21, 2:56 AM CST	Mesoscale Discussion	SPC	Aransas, Bee, Brazoria, Calhoun, Colorado, DeWitt and 12 more	5 hr

Nearby

Mesoscale Discussions in Louisiana, 2025 Mesoscale Discussions in Texas, 2025 Every mesoscale discussion in 2025

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.