Alert archive / Mississippi / Mesoscale Discussions in 2020

Mesoscale Discussion 461

April 23, 20209 counties in Alabama; 9 parishes in Louisiana; 27 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 23, 2020, 1:37 PM CDT for 9 counties in Alabama; 9 parishes in Louisiana; 27 counties in Mississippi. It was in force for 113 min.

The area

The outline as issued.

The facts

Issued: Apr 23, 2020, 1:37 PM CDT (18:37 UTC)
Expired: Apr 23, 2020, 3:30 PM CDT
In force: 113 min
Issued by: the Storm Prediction Center
Chance of a watch: 40%

All 45 counties

Choctaw County, AL, Clarke County, AL, Greene County, AL, Hale County, AL, Marengo County, AL, Perry County, AL, Pickens County, AL, Sumter County, AL, Washington County, AL, Ascension Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Iberville Parish, LA, Livingston Parish, LA, Saint Helena Parish, LA, Tangipahoa Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, Amite County, MS, Clarke County, MS, Covington County, MS, Forrest County, MS, Greene County, MS, Jasper County, MS, Jefferson Davis County, MS, Jones County, MS, Kemper County, MS, Lamar County, MS, Lauderdale County, MS, Lawrence County, MS, Lincoln County, MS, Lowndes County, MS, Marion County, MS, Neshoba County, MS, Newton County, MS, Noxubee County, MS, Pearl River County, MS, Perry County, MS, Pike County, MS, Scott County, MS, Simpson County, MS, Smith County, MS, Stone County, MS, Walthall County, MS, Wayne County, MS

The radar

The Jackson/Brandon,MS radar (KDGX), 89 km from the middle of the area, began a volume at 18:40 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.

Severe Thunderstorm Watch 142Apr 23, 4:05 PM CDT

The nearest sounding before it

Jackson, MS (KJAN), launched 12:00Z, 6.6 hours before the alert went out and 98 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: 1085 J/kg
Mixed-layer CIN: -31 J/kg
Mixed-layer LCL: 625 m above ground
0-6 km bulk shear: 89 kt
0-1 km storm-relative helicity: 259 m²/s²
0-3 km storm-relative helicity: 258 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 4.4

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 23, 2:28 AM CDT	Mesoscale Discussion	SPC	Baldwin, Choctaw, Clarke, Conecuh, Escambia, Mobile and 2 more	92 min
Apr 23, 4:05 AM CDT	Tornado Watch	SPC	Baldwin, Barbour, Bullock, Butler, Choctaw, Clarke and 14 more	11 hr
Apr 23, 7:43 AM CDT	Mesoscale Discussion	SPC	Baldwin, Barbour, Butler, Coffee, Conecuh, Covington and 9 more	92 min
Apr 23, 9:29 AM CDT	Mesoscale Discussion	SPC	Houston	61 min
Apr 23, 4:06 PM CDT	Severe Thunderstorm Watch	SPC	Autauga, Bibb, Chambers, Chilton, Choctaw, Clarke and 17 more	113 min
Apr 22, 7:01 PM CDT	Mesoscale Discussion	SPC	Beauregard, Vernon	89 min
Apr 22, 7:41 PM CDT	Mesoscale Discussion	SPC	Vernon	34 min
Apr 22, 8:26 PM CDT	Mesoscale Discussion	SPC	De Soto, Natchitoches, Sabine	94 min
Apr 22, 9:31 PM CDT	Mesoscale Discussion	SPC	Avoyelles, Concordia, East Feliciana, Pointe Coupee, Saint Helena, Washington and 1 more	89 min
Apr 22, 9:47 PM CDT	Tornado Watch	SPC	Ascension, Catahoula, Concordia, East Baton Rouge, East Feliciana, Franklin and 12 more	9 hr
Apr 22, 10:17 PM CDT	Mesoscale Discussion	SPC	Caldwell, Grant, LaSalle, Natchitoches, Sabine, Winn	88 min
Apr 22, 11:16 PM CDT	Mesoscale Discussion	SPC	Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Caldwell and 15 more	89 min
Apr 23, 12:02 AM CDT	Tornado Watch	SPC	Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Evangeline and 5 more	4 hr

Nearby

Mesoscale Discussions in Mississippi, 2020 Mesoscale Discussions in Alabama, 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.