Alert archive / Louisiana / Mesoscale Discussions in 2007

Mesoscale Discussion 591

April 25, 2007Mobile County, Washington County, Alabama; 15 parishes in Louisiana; 15 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 25, 2007, 11:50 PM CDT for Mobile County, Washington County, Alabama; 15 parishes in Louisiana; 15 counties in Mississippi. It was in force for 85 min.

The area

The outline as issued.

The facts

Issued
Apr 25, 2007, 11:50 PM CDT (04:50 UTC)
Expired
Apr 26, 2007, 1:15 AM CDT
In force
85 min
Issued by
the Storm Prediction Center
All 32 counties

Mobile County, AL, Washington County, AL, Ascension Parish, LA, Assumption Parish, LA, Jefferson Parish, LA, Lafourche Parish, LA, Livingston Parish, LA, Orleans Parish, LA, Plaquemines Parish, LA, Saint Bernard Parish, LA, Saint Charles Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Tammany Parish, LA, Tangipahoa Parish, LA, Terrebonne Parish, LA, Washington Parish, LA, Clarke County, MS, Covington County, MS, Forrest County, MS, George County, MS, Greene County, MS, Hancock County, MS, Harrison County, MS, Jackson County, MS, Jones County, MS, Lamar County, MS, Marion County, MS, Pearl River County, MS, Perry County, MS, Stone 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 00:00Z, 4.8 hours before the alert went out and 10 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 00:00Z on 2007-04-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 583 joules per kilogram.LCLEL10008507005003002001001 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 00:00Z on 2007-04-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 36 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
583 J/kg
Mixed-layer CIN
-2 J/kg
Mixed-layer LCL
1060 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
36 m²/s²
0-3 km storm-relative helicity
77 m²/s²
Significant tornado parameter
0.1
Supercell composite
0.5

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 26, 12:41 AM CDTTornado WatchSPCBaldwin, Choctaw, Clarke, Mobile, Washington7 hr
Apr 26, 4:46 AM CDTMesoscale DiscussionSPCBaldwin, Choctaw, Clarke, Marengo, Mobile, Monroe and 1 more89 min
Apr 26, 7:12 AM CDTMesoscale DiscussionSPCBaldwin, Clarke, Mobile, Monroe, Washington93 min
Apr 26, 2:12 PM CDTMesoscale DiscussionSPCBarbour, Bullock, Chambers, Coffee, Covington, Crenshaw and 12 more63 min
Apr 26, 2:42 PM CDTTornado WatchSPCBarbour, Bullock, Coffee, Dale, Geneva, Henry and 3 more3 hr
Apr 26, 4:33 PM CDTMesoscale DiscussionSPCCherokee, DeKalb, Etowah, Jackson, Marshall57 min
Apr 26, 4:53 PM CDTTornado WatchSPCDeKalb, Jackson, Marshall5 hr
Apr 26, 5:26 PM CDTMesoscale DiscussionSPCHenry, Houston64 min

Nearby

Mesoscale Discussions in Louisiana, 2007Mesoscale Discussions in Mississippi, 2007Mesoscale Discussions in Alabama, 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.