Alert archive / Mississippi / Mesoscale Discussions in 2018

Mesoscale Discussion 281

April 22, 20184 states

The Storm Prediction Center issued this mesoscale discussion at Apr 22, 2018, 10:37 AM CDT for 4 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Apr 22, 2018, 10:37 AM CDT (15:37 UTC)
Expired: Apr 22, 2018, 1:00 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 20%

All 28 counties

Baldwin County, AL, Choctaw County, AL, Clarke County, AL, Mobile County, AL, Washington County, AL, Escambia County, FL, Orleans Parish, LA, Plaquemines Parish, LA, Saint Bernard Parish, LA, Saint Tammany Parish, LA, Washington Parish, LA, Clarke County, MS, Covington County, MS, Forrest County, MS, George County, MS, Greene County, MS, Hancock County, MS, Harrison County, MS, Jackson County, MS, Jefferson Davis County, MS, Jones County, MS, Lamar County, MS, Marion County, MS, Pearl River County, MS, Perry County, MS, Stone County, MS, Walthall County, MS, Wayne County, MS

The radar

The Mobile radar (KMOB), 94 km from the middle of the area, began a volume at 15:39 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

Slidell Radar S, LA (KSIL), launched 12:00Z, 3.6 hours before the alert went out and 89 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: 55 J/kg
Mixed-layer CIN: -18 J/kg
Mixed-layer LCL: 739 m above ground
0-6 km bulk shear: 48 kt
0-1 km storm-relative helicity: 283 m²/s²
0-3 km storm-relative helicity: 351 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 2.4

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 22, 1:58 PM CDT	Mesoscale Discussion	SPC	Baldwin, Barbour, Butler, Coffee, Conecuh, Covington and 8 more	3 hr
Apr 22, 2:55 PM CDT	Tornado Watch	SPC	Barbour, Bullock, Coffee, Covington, Crenshaw, Dale and 8 more	8 hr
Apr 22, 3:58 PM CDT	Mesoscale Discussion	SPC	Autauga, Bibb, Chilton, Dallas, Fayette, Greene and 11 more	3 hr

Nearby

Mesoscale Discussions in Mississippi, 2018 Mesoscale Discussions in Alabama, 2018 Mesoscale Discussions in Louisiana, 2018 Every mesoscale discussion in 2018

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.