Alert archive / Mississippi / Mesoscale Discussions in 2003

Mesoscale Discussion 817

May 7, 200320 parishes in Louisiana; 31 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at May 7, 2003, 9:47 AM CDT for 20 parishes in Louisiana; 31 counties in Mississippi. It was in force for 118 min.

The area

The outline as issued.

The facts

Issued
May 7, 2003, 9:47 AM CDT (14:47 UTC)
Expired
May 7, 2003, 11:45 AM CDT
In force
118 min
Issued by
the Storm Prediction Center
All 51 counties

Bienville Parish, LA, Caldwell Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, East Carroll Parish, LA, Franklin Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Red River Parish, LA, Richland Parish, LA, Tensas Parish, LA, Union Parish, LA, West Carroll Parish, LA, Winn Parish, LA, Adams County, MS, Attala County, MS, Calhoun County, MS, Carroll County, MS, Chickasaw County, MS, Choctaw County, MS, Claiborne County, MS, Clay County, MS, Copiah County, MS, Franklin County, MS, Grenada County, MS, Hinds County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Jefferson County, MS, Leake County, MS, Lincoln County, MS, Madison County, MS, Monroe County, MS, Montgomery County, MS, Neshoba County, MS, Oktibbeha County, MS, Rankin County, MS, Scott County, MS, Sharkey County, MS, Simpson County, MS, Warren County, MS, Webster County, MS, Winston County, MS, Yazoo 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

Jackson, MS (KJAN), launched 12:00Z, 2.8 hours before the alert went out and 101 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, Jackson, MS at 12:00Z on 2003-05-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1680 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, Jackson, MS at 12:00Z on 2003-05-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 120 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
1680 J/kg
Mixed-layer CIN
-38 J/kg
Mixed-layer LCL
548 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
120 m²/s²
0-3 km storm-relative helicity
180 m²/s²
Significant tornado parameter
0.7
Supercell composite
4.0

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
May 6, 7:15 PM CDTSevere Thunderstorm WatchSPCCatahoula, Concordia, East Carroll, Franklin, Madison, Morehouse and 3 more5 hr
May 6, 9:53 PM CDTMesoscale DiscussionSPCMadison97 min
May 6, 11:30 PM CDTTornado WatchSPCBienville, Bossier, Caddo, Claiborne, Jackson, Lincoln and 5 more6 hr
May 7, 2:27 AM CDTMesoscale DiscussionSPCBienville, Bossier, Caddo, Caldwell, Claiborne, De Soto and 12 more3 hr
May 7, 4:55 AM CDTTornado WatchSPCBienville, East Carroll, Jackson, Lincoln, Madison, Morehouse and 4 more6 hr
May 7, 7:06 AM CDTMesoscale DiscussionSPCBienville, East Carroll, Jackson, Lincoln, Madison, Morehouse and 4 more114 min
May 7, 10:50 AM CDTTornado WatchSPCEast Carroll, Franklin, Madison, Morehouse, Richland, Tensas and 1 more5 hr
May 7, 1:54 PM CDTMesoscale DiscussionSPCEast Carroll, Franklin, Madison, Richland, Tensas, West Carroll2 hr
May 6, 11:50 PM CDTTornado WatchSPCAlcorn, Benton, DeSoto, Marshall, Prentiss, Tate and 4 more6 hr
May 7, 1:41 AM CDTMesoscale DiscussionSPCAlcorn, Benton, DeSoto, Marshall, Prentiss, Tate and 4 more3 hr
May 7, 7:35 AM CDTTornado WatchSPCKemper, Lauderdale, Lowndes, Monroe, Neshoba, Newton and 4 more5 hr
May 7, 1:42 PM CDTMesoscale DiscussionSPCClarke, Covington, Forrest, George, Greene, Harrison and 8 more2 hr
May 7, 3:00 PM CDTTornado WatchSPCLowndes6 hr
May 7, 6:29 PM CDTMesoscale DiscussionSPCClarke, Jasper, Lauderdale, Lowndes, Newton, Wayne91 min

Nearby

Mesoscale Discussions in Mississippi, 2003Mesoscale Discussions in Louisiana, 2003Every mesoscale discussion in 2003

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.