Alert archive / Louisiana / Severe Thunderstorm Watches in 2007

Severe Thunderstorm Watch 217

May 3, 200720 parishes in Louisiana; 17 counties in Mississippi

The Storm Prediction Center issued this severe thunderstorm watch at May 3, 2007, 11:27 AM CDT for 20 parishes in Louisiana; 17 counties in Mississippi. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
May 3, 2007, 11:27 AM CDT (16:27 UTC)
Expired
May 3, 2007, 3:49 PM CDT
In force
4 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt
All 37 counties

Ascension Parish, LA, Assumption Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Iberville 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 Helena 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, West Baton Rouge Parish, LA, Amite County, MS, Covington County, MS, Forrest County, MS, Franklin County, MS, Hancock County, MS, Harrison County, MS, Jefferson Davis County, MS, Jones County, MS, Lamar County, MS, Lawrence County, MS, Lincoln County, MS, Marion County, MS, Pearl River County, MS, Perry County, MS, Pike County, MS, Stone County, MS, Walthall County, MS

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes
5%
One or more EF2 to EF5 tornadoes
5%
Ten or more severe wind reports
40%
One or more gusts of 65 knots or more
30%
Ten or more severe hail reports
40%
One or more hailstones of 2 inches or more
20%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

5 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
May 3, 11:31 AM CDTSevere Thunderstorm WarningLIXAscension, East Baton Rouge, Livingston31 min
May 3, 12:51 PM CDTSevere Thunderstorm WarningJANFranklin, Lincoln54 min
May 3, 1:43 PM CDTSevere Thunderstorm WarningJANLincoln30 min
May 3, 1:45 PM CDTSevere Thunderstorm WarningJANLawrence60 min
May 3, 2:09 PM CDTSevere Thunderstorm WarningJANJefferson Davis, Marion51 min

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 4.5 hours before the alert went out and 46 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 2007-05-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1300 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 2007-05-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 35 square meters per square second.1939Sfc1 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
1300 J/kg
Mixed-layer CIN
-7 J/kg
Mixed-layer LCL
589 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
35 m²/s²
0-3 km storm-relative helicity
43 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.8

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 2, 7:24 PM CDTMesoscale DiscussionSPCBienville, Bossier, Caddo, Claiborne, De Soto, Lincoln and 3 more96 min
May 2, 7:59 PM CDTTornado WatchSPCBienville, Bossier, Caddo, Claiborne, De Soto, Grant and 7 more7 hr
May 2, 11:09 PM CDTMesoscale DiscussionSPCBienville, Bossier, Caddo, Claiborne, De Soto, Natchitoches and 4 more96 min
May 3, 1:21 AM CDTMesoscale DiscussionSPCBienville, Bossier, Caddo, Claiborne, De Soto, Grant and 8 more84 min
May 3, 3:08 PM CDTTornado WatchSPCAllen, Beauregard, Calcasieu, Cameron, De Soto, Grant and 6 more7 hr
May 3, 4:46 PM CDTMesoscale DiscussionSPCEast Carroll, Madison, Morehouse, Richland, West Carroll59 min
May 3, 5:38 PM CDTTornado WatchSPCEast Carroll3 hr
May 3, 6:27 PM CDTTornado WatchSPCAvoyelles, Caldwell, Catahoula, Concordia, Franklin, LaSalle and 3 more4 hr
May 3, 6:34 PM CDTMesoscale DiscussionSPCAllen, Beauregard, Calcasieu, Cameron, De Soto, Grant and 4 more116 min
May 3, 3:22 PM CDTMesoscale DiscussionSPCAttala, Choctaw, Clay, Jasper, Kemper, Lauderdale and 10 more53 min

Nearby

Severe Thunderstorm Watches in Louisiana, 2007Severe Thunderstorm Watches in Mississippi, 2007Every severe thunderstorm watch 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.