Alert archive / Louisiana / Mesoscale Discussions in 2007

Mesoscale Discussion 487

April 14, 200720 parishes in Louisiana; 17 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 14, 2007, 1:34 AM CDT for 20 parishes in Louisiana; 17 counties in Mississippi. It was in force for 56 min.

The area

The outline as issued.

The facts

Issued
Apr 14, 2007, 1:34 AM CDT (06:34 UTC)
Expired
Apr 14, 2007, 2:30 AM CDT
In force
56 min
Issued by
the Storm Prediction Center
All 37 counties

Allen Parish, LA, Avoyelles Parish, LA, Caldwell Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, East Carroll Parish, LA, Evangeline Parish, LA, Franklin Parish, LA, Grant Parish, LA, LaSalle Parish, LA, Madison Parish, LA, Pointe Coupee Parish, LA, Rapides Parish, LA, Richland Parish, LA, Saint Landry Parish, LA, Tensas Parish, LA, Vernon Parish, LA, West Carroll Parish, LA, West Feliciana Parish, LA, Winn Parish, LA, Adams County, MS, Carroll County, MS, Claiborne County, MS, Copiah County, MS, Franklin County, MS, Hinds County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Jefferson County, MS, Madison County, MS, Rankin County, MS, Sharkey County, MS, Warren County, MS, Washington County, MS, Wilkinson 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 00:00Z, 6.6 hours before the alert went out and 170 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 00:00Z on 2007-04-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 00:00Z on 2007-04-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 151 square meters per square second.19395878Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2703 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
151 m²/s²
0-3 km storm-relative helicity
468 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

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 13, 8:42 PM CDTMesoscale DiscussionSPCAllen, Avoyelles, Beauregard, Bienville, Bossier, Caddo and 22 more2 hr
Apr 14, 1:41 AM CDTTornado WatchSPCAllen, Avoyelles, Beauregard, Caldwell, Catahoula, Concordia and 19 more6 hr
Apr 14, 6:17 AM CDTMesoscale DiscussionSPCAscension, Assumption, East Baton Rouge, East Feliciana, Iberville, Lafayette and 13 more88 min
Apr 14, 7:11 AM CDTSevere Thunderstorm WatchSPCEast Baton Rouge, East Feliciana, Livingston, Pointe Coupee, Saint Helena, Saint Tammany and 4 more6 hr
Apr 14, 5:04 PM CDTMesoscale DiscussionSPCPlaquemines, Saint Bernard56 min
Apr 13, 10:55 PM CDTMesoscale DiscussionSPCBolivar, Coahoma, Humphreys, Leflore, Quitman, Sunflower and 2 more95 min
Apr 14, 10:07 AM CDTMesoscale DiscussionSPCGeorge, Greene, Harrison, Jackson53 min
Apr 14, 10:26 AM CDTTornado WatchSPCClarke, Forrest, George, Greene, Hancock, Harrison and 5 more7 hr
Apr 14, 2:12 PM CDTMesoscale DiscussionSPCClarke, Forrest, George, Greene, Hancock, Harrison and 5 more63 min
Apr 14, 5:26 PM CDTTornado WatchSPCGeorge, Greene, Jackson, Perry, Stone, Wayne6 hr

Nearby

Mesoscale Discussions in Louisiana, 2007Mesoscale Discussions in Mississippi, 2007Every mesoscale discussion in 2007

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.