Alert archive / Mississippi / Mesoscale Discussions in 2011

Mesoscale Discussion 2126

September 4, 20115 states

The Storm Prediction Center issued this mesoscale discussion at Sep 4, 2011, 6:29 PM CDT for 5 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Sep 4, 2011, 6:29 PM CDT (23:29 UTC)
Expired
Sep 4, 2011, 8:30 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
All 98 counties

Autauga County, AL, Baldwin County, AL, Barbour County, AL, Bullock County, AL, Butler County, AL, Choctaw County, AL, Clarke County, AL, Coffee County, AL, Conecuh County, AL, Covington County, AL, Crenshaw County, AL, Dale County, AL, Dallas County, AL, Escambia County, AL, Geneva County, AL, Hale County, AL, Henry County, AL, Houston County, AL, Lowndes County, AL, Marengo County, AL, Mobile County, AL, Monroe County, AL, Montgomery County, AL, Perry County, AL, Pike County, AL, Sumter County, AL, Washington County, AL, Wilcox County, AL, Bay County, FL, Calhoun County, FL, Dixie County, FL, Escambia County, FL, Franklin County, FL, Gadsden County, FL, Gulf County, FL, Holmes County, FL, Jackson County, FL, Jefferson County, FL, Lafayette County, FL, Leon County, FL, Liberty County, FL, Madison County, FL, Okaloosa County, FL, Santa Rosa County, FL, Taylor County, FL, Wakulla County, FL, Walton County, FL, Washington County, FL, Baker County, GA, Calhoun County, GA, Clay County, GA, Decatur County, GA, Early County, GA, Grady County, GA, Miller County, GA, Mitchell County, GA, Seminole County, GA, Thomas County, GA, Jefferson Parish, LA, Lafourche Parish, LA, Orleans Parish, LA, Plaquemines Parish, LA, Saint Bernard Parish, LA, Saint Charles Parish, LA, Saint John the Baptist Parish, LA, Saint Tammany Parish, LA, Terrebonne Parish, LA, Washington Parish, LA, Clarke County, MS, Copiah County, MS, Covington County, MS, Forrest County, MS, George County, MS, Greene County, MS, Hancock County, MS, Harrison County, MS, Jackson 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, Marion County, MS, Neshoba County, MS, Newton County, MS, Pearl River County, MS, Perry County, MS, Pike County, MS, Rankin County, MS, Scott County, MS, Simpson County, MS, Smith County, MS, Stone County, MS, Walthall County, MS, Wayne County, MS

The radar

The Mobile radar (KMOB), 87 km from the middle of the area, began a volume at 23:31 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.

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 11.5 hours before the alert went out and 184 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-pSkew-T log-p diagram, Slidell Radar S, LA at 12:00Z on 2011-09-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2528 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Slidell Radar S, LA at 12:00Z on 2011-09-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 249 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
2528 J/kg
Mixed-layer CIN
-8 J/kg
Mixed-layer LCL
473 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
249 m²/s²
0-3 km storm-relative helicity
287 m²/s²
Significant tornado parameter
3.0
Supercell composite
18.9

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 3, 9:43 PM CDTTornado WatchSPCBaldwin, Butler, Choctaw, Clarke, Conecuh, Covington and 6 more9 hr
Sep 3, 11:35 PM CDTMesoscale DiscussionSPCBaldwin, Escambia, Mobile, Washington115 min
Sep 4, 4:30 AM CDTMesoscale DiscussionSPCBaldwin, Clarke, Conecuh, Escambia, Mobile, Monroe and 1 more60 min
Sep 4, 5:05 AM CDTTornado WatchSPCBaldwin, Butler, Choctaw, Clarke, Coffee, Conecuh and 8 more11 hr
Sep 4, 9:50 AM CDTMesoscale DiscussionSPCBaldwin, Butler, Choctaw, Clarke, Coffee, Conecuh and 12 more85 min
Sep 4, 11:41 AM CDTTornado WatchSPCCoffee, Dale, Geneva, Henry, Houston10 hr
Sep 4, 2:47 PM CDTMesoscale DiscussionSPCAutauga, Baldwin, Bibb, Butler, Chilton, Choctaw and 26 more88 min
Sep 4, 3:47 PM CDTTornado WatchSPCAutauga, Baldwin, Butler, Choctaw, Clarke, Conecuh and 13 more6 hr
Sep 4, 11:27 AM CDTMesoscale DiscussionSPCCalhoun, Gadsden, Jackson, Jefferson, Leon, Liberty and 2 more33 min

Nearby

Mesoscale Discussions in Mississippi, 2011Mesoscale Discussions in Alabama, 2011Mesoscale Discussions in Florida, 2011Every mesoscale discussion in 2011

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.