Alert archive / Mississippi / Mesoscale Discussions in 2006

Mesoscale Discussion 604

April 21, 200613 counties in Alabama; 11 parishes in Louisiana; 32 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 21, 2006, 12:52 PM CDT for 13 counties in Alabama; 11 parishes in Louisiana; 32 counties in Mississippi. It was in force for 83 min.

The area

The outline as issued.

The facts

Issued
Apr 21, 2006, 12:52 PM CDT (17:52 UTC)
Expired
Apr 21, 2006, 2:15 PM CDT
In force
83 min
Issued by
the Storm Prediction Center
All 56 counties

Baldwin County, AL, Choctaw County, AL, Clarke County, AL, Dallas County, AL, Greene County, AL, Hale County, AL, Marengo County, AL, Mobile County, AL, Monroe County, AL, Perry County, AL, Sumter County, AL, Washington County, AL, Wilcox County, AL, Jefferson Parish, LA, Lafourche Parish, LA, Orleans Parish, LA, Plaquemines Parish, LA, Saint Bernard Parish, LA, Saint Charles Parish, LA, Saint Helena Parish, LA, Saint John the Baptist Parish, LA, Saint Tammany Parish, LA, Tangipahoa Parish, LA, Washington Parish, LA, Amite County, MS, 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, Leake 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 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, 5.9 hours before the alert went out and 135 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 2006-04-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1172 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 2006-04-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 57 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
1172 J/kg
Mixed-layer CIN
-12 J/kg
Mixed-layer LCL
699 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
57 m²/s²
0-3 km storm-relative helicity
55 m²/s²
Significant tornado parameter
0.3
Supercell composite
1.7

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
Apr 20, 7:55 PM CDTMesoscale DiscussionSPCCherokee, Clay, Cleburne, Randolph2 hr
Apr 20, 10:53 PM CDTMesoscale DiscussionSPCAutauga, Bibb, Blount, Chilton, Colbert, Cullman and 14 more97 min
Apr 21, 2:15 AM CDTMesoscale DiscussionSPCBlount, Cherokee, Colbert, Cullman, DeKalb, Etowah and 13 more2 hr
Apr 21, 5:00 AM CDTMesoscale DiscussionSPCColbert, Franklin, Lauderdale, Lawrence, Limestone, Marion and 2 more60 min
Apr 21, 12:17 PM CDTMesoscale DiscussionSPCBibb, Blount, Calhoun, Cherokee, Chilton, Clay and 17 more88 min
Apr 21, 1:24 PM CDTSevere Thunderstorm WatchSPCAutauga, Baldwin, Bibb, Blount, Butler, Calhoun and 45 more8 hr
Apr 21, 3:39 PM CDTMesoscale DiscussionSPCAutauga, Barbour, Bibb, Bullock, Butler, Calhoun and 37 more66 min
Apr 20, 10:00 PM CDTSevere Thunderstorm WatchSPCBossier, Caddo, Claiborne, De Soto, Union, Webster7 hr
Apr 20, 11:26 PM CDTMesoscale DiscussionSPCBeauregard, Bienville, Caldwell, De Soto, Franklin, Grant and 10 more94 min
Apr 21, 9:51 AM CDTMesoscale DiscussionSPCAcadia, Ascension, Assumption, Avoyelles, Concordia, East Baton Rouge and 23 more84 min
Apr 21, 10:16 AM CDTSevere Thunderstorm WatchSPCAcadia, Ascension, Assumption, Avoyelles, Catahoula, Concordia and 30 more6 hr
Apr 20, 7:35 PM CDTMesoscale DiscussionSPCAttala, Bolivar, Calhoun, Carroll, Chickasaw, Choctaw and 26 more85 min
Apr 20, 9:31 PM CDTMesoscale DiscussionSPCAlcorn, Benton, Coahoma, DeSoto, Lafayette, Marshall and 5 more89 min
Apr 21, 12:04 AM CDTMesoscale DiscussionSPCAlcorn, Benton, Itawamba, Lafayette, Lee, Marshall and 8 more116 min

Nearby

Mesoscale Discussions in Mississippi, 2006Mesoscale Discussions in Alabama, 2006Mesoscale Discussions in Louisiana, 2006Every mesoscale discussion in 2006

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.