Alert archive / Mississippi / Mesoscale Discussions in 2020

Mesoscale Discussion 447

April 22, 20204 parishes in Louisiana; 16 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 22, 2020, 6:47 PM CDT for 4 parishes in Louisiana; 16 counties in Mississippi. It was in force for 88 min.

The area

The outline as issued.

The facts

Issued: Apr 22, 2020, 6:47 PM CDT (23:47 UTC)
Expired: Apr 22, 2020, 8:15 PM CDT
In force: 88 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

Counties Concordia Parish, LA, Saint Helena Parish, LA, Tensas Parish, LA, Washington Parish, LA, Adams County, MS, Amite County, MS, Claiborne County, MS, Copiah County, MS, Forrest County, MS, Franklin County, MS, Jefferson County, MS, Jefferson Davis County, MS, Lamar County, MS, Lawrence County, MS, Lincoln County, MS, Marion County, MS, Pearl River County, MS, Pike County, MS, Walthall County, MS, Wilkinson County, MS

The radar

The Jackson/Brandon,MS radar (KDGX), 101 km from the middle of the area, began a volume at 23:47 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 137Apr 22, 9:45 PM CDT

The nearest sounding before it

Jackson, MS (KJAN), launched 12:00Z, 11.8 hours before the alert went out and 99 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: 2461 m above ground
0-6 km bulk shear: 59 kt
0-1 km storm-relative helicity: 92 m²/s²
0-3 km storm-relative helicity: 215 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
Apr 22, 10:38 AM CDT	Mesoscale Discussion	SPC	Caddo, De Soto, Natchitoches, Red River, Sabine, Vernon	2 hr
Apr 22, 10:55 AM CDT	Tornado Watch	SPC	Allen, Beauregard, De Soto, Evangeline, Grant, Natchitoches and 4 more	6 hr
Apr 22, 1:10 PM CDT	Mesoscale Discussion	SPC	Allen, Beauregard, Calcasieu, De Soto, Evangeline, Grant and 6 more	65 min
Apr 22, 2:53 PM CDT	Mesoscale Discussion	SPC	Bienville, De Soto, Grant, LaSalle, Natchitoches, Rapides and 4 more	67 min
Apr 22, 4:24 PM CDT	Mesoscale Discussion	SPC	Allen, Avoyelles, Beauregard, Bienville, Caldwell, Catahoula and 16 more	96 min
Apr 22, 5:01 PM CDT	Tornado Watch	SPC	Allen, Avoyelles, Beauregard, Bienville, Bossier, Caddo and 17 more	9 hr

Nearby

Mesoscale Discussions in Mississippi, 2020 Mesoscale Discussions in Louisiana, 2020 Every mesoscale discussion in 2020

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.