Alert archive / Louisiana / Mesoscale Discussions in 2019

Mesoscale Discussion 25

January 19, 201917 parishes in Louisiana; 6 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Jan 19, 2019, 1:24 AM CST for 17 parishes in Louisiana; 6 counties in Mississippi. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Jan 19, 2019, 1:24 AM CST (07:24 UTC)
Expired: Jan 19, 2019, 3:30 AM CST
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 40%

All 23 counties

Allen Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Caldwell Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, East Carroll Parish, LA, Evangeline Parish, LA, Franklin Parish, LA, Grant Parish, LA, LaSalle Parish, LA, Madison Parish, LA, Rapides Parish, LA, Richland Parish, LA, Tensas Parish, LA, Vernon Parish, LA, Winn Parish, LA, Adams County, MS, Claiborne County, MS, Issaquena County, MS, Jefferson County, MS, Sharkey County, MS, Warren County, MS

The radar

The Ft Polk radar (KPOE), 91 km from the middle of the area, began a volume at 07:26 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 1Jan 19, 5:20 AM CST

The nearest sounding before it

Shreveport, LA (KBAD), launched 00:00Z, 7.4 hours before the alert went out and 181 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: 307 J/kg
Mixed-layer CIN: -107 J/kg
Mixed-layer LCL: 443 m above ground
0-6 km bulk shear: 53 kt
0-1 km storm-relative helicity: 395 m²/s²
0-3 km storm-relative helicity: 531 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 10.7

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 19, 5:04 AM CST	Mesoscale Discussion	SPC	Avoyelles, Concordia, East Feliciana, Evangeline, Pointe Coupee, Saint Helena and 3 more	116 min
Jan 19, 5:23 AM CST	Tornado Watch	SPC	Ascension, East Baton Rouge, East Feliciana, Iberville, Livingston, Pointe Coupee and 6 more	8 hr
Jan 19, 9:08 AM CST	Mesoscale Discussion	SPC	George, Greene, Perry, Wayne	2 hr
Jan 19, 9:43 AM CST	Tornado Watch	SPC	George, Greene, Perry, Stone, Wayne	7 hr
Jan 19, 11:37 AM CST	Mesoscale Discussion	SPC	George, Greene, Harrison, Jackson, Perry, Stone and 1 more	83 min

Nearby

Mesoscale Discussions in Louisiana, 2019 Mesoscale Discussions in Mississippi, 2019 Every mesoscale discussion in 2019

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.