Alert archive / Louisiana / Mesoscale Discussions in 2017

Mesoscale Discussion 1112

June 21, 20174 states

The Storm Prediction Center issued this mesoscale discussion at Jun 21, 2017, 6:29 PM CDT for 4 states. It was in force for 61 min.

The area

The outline as issued.

The facts

Issued: Jun 21, 2017, 6:29 PM CDT (23:29 UTC)
Expired: Jun 21, 2017, 7:30 PM CDT
In force: 61 min
Issued by: the Storm Prediction Center

All 56 counties

Baldwin County, AL, Conecuh County, AL, Covington County, AL, Escambia County, AL, Mobile County, AL, Washington County, AL, Escambia County, FL, Okaloosa County, FL, Santa Rosa County, FL, Acadia Parish, LA, Ascension Parish, LA, Assumption Parish, LA, Avoyelles Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Evangeline Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jefferson Davis Parish, LA, Jefferson Parish, LA, Lafayette Parish, LA, Lafourche Parish, LA, Livingston Parish, LA, Orleans Parish, LA, Plaquemines Parish, LA, Pointe Coupee Parish, LA, Saint Bernard Parish, LA, Saint Charles Parish, LA, Saint Helena Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, Saint Tammany Parish, LA, St. Mary Parish, LA, Tangipahoa Parish, LA, Terrebonne Parish, LA, Vermilion Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Amite County, MS, Forrest County, MS, George County, MS, Greene County, MS, Hancock County, MS, Harrison County, MS, Jackson County, MS, Lamar County, MS, Marion County, MS, Pearl River County, MS, Perry County, MS, Pike County, MS, Stone County, MS, Walthall County, MS, Wilkinson County, MS

The watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Tornado Watch 362Jun 21, 6:45 PM CDT

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 11.5 hours before the alert went out and 3 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: 262 J/kg
Mixed-layer CIN: -75 J/kg
Mixed-layer LCL: 465 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 485 m²/s²
0-3 km storm-relative helicity: 506 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 5.3

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
Jun 20, 8:15 PM CDT	Mesoscale Discussion	SPC	Baldwin, Mobile	3 hr
Jun 20, 9:48 PM CDT	Mesoscale Discussion	SPC	Baldwin, Mobile	57 min
Jun 20, 10:24 PM CDT	Tornado Watch	SPC	Baldwin, Mobile	12 hr
Jun 21, 2:08 AM CDT	Mesoscale Discussion	SPC	Baldwin, Mobile	2 hr
Jun 21, 7:47 AM CDT	Mesoscale Discussion	SPC	Baldwin, Mobile	118 min
Jun 21, 10:01 AM CDT	Tornado Watch	SPC	Baldwin, Covington, Escambia, Mobile	9 hr
Jun 21, 3:42 PM CDT	Mesoscale Discussion	SPC	Baldwin, Mobile	93 min
Jun 21, 6:45 PM CDT	Tornado Watch	SPC	Baldwin, Butler, Clarke, Conecuh, Covington, Crenshaw and 5 more	8 hr

Nearby

Mesoscale Discussions in Louisiana, 2017 Mesoscale Discussions in Mississippi, 2017 Mesoscale Discussions in Alabama, 2017 Every mesoscale discussion in 2017

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.