Alert archive / Louisiana / Severe Thunderstorm Watches in 2010

Severe Thunderstorm Watch 710

October 24, 201017 parishes in Louisiana; 13 counties in Texas

The Storm Prediction Center issued this severe thunderstorm watch at Oct 24, 2010, 9:57 PM CDT for 17 parishes in Louisiana; 13 counties in Texas. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Oct 24, 2010, 9:57 PM CDT (02:57 UTC)
Expired
Oct 25, 2010, 4:00 AM CDT
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
2.5 in
Strongest gust expected
60 kt
All 30 counties

Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Caldwell Parish, LA, Claiborne Parish, LA, De Soto Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Red River Parish, LA, Sabine Parish, LA, Union Parish, LA, Webster Parish, LA, Winn Parish, LA, Anderson County, TX, Cherokee County, TX, Gregg County, TX, Harrison County, TX, Henderson County, TX, Kaufman County, TX, Marion County, TX, Nacogdoches County, TX, Panola County, TX, Rusk County, TX, Shelby County, TX, Smith County, TX, Van Zandt County, TX

The radar

The Shreveport radar (KSHV), 46 km from the middle of the area, began a volume at 02:59 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What SPC expected

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

Two or more tornadoes
20%
One or more EF2 to EF5 tornadoes
5%
Ten or more severe wind reports
30%
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
30%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Oct 24, 10:07 PM CDTSevere Thunderstorm WarningSHVBossier, Caddo53 min
Oct 24, 10:33 PM CDTSevere Thunderstorm WarningSHVBossier, Claiborne, Webster57 min
Oct 24, 10:41 PM CDTSevere Thunderstorm WarningSHVCherokee, Rusk, Smith49 min
Oct 24, 10:44 PM CDTSevere Thunderstorm WarningSHVCherokee, Smith31 min
Oct 24, 10:58 PM CDTSevere Thunderstorm WarningSHVHarrison32 min
Oct 25, 12:33 AM CDTSevere Thunderstorm WarningSHVBienville, Bossier, Claiborne, Lincoln, Webster57 min
Oct 25, 1:31 AM CDTSevere Thunderstorm WarningSHVBienville, Claiborne, Lincoln, Webster44 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Shreveport, LA (KSHV), launched 00:00Z, 3.0 hours before the alert went out and 39 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, Shreveport, LA at 00:00Z on 2010-10-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 968 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, Shreveport, LA at 00:00Z on 2010-10-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 102 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
968 J/kg
Mixed-layer CIN
-50 J/kg
Mixed-layer LCL
1928 m above ground
0-6 km bulk shear
48 kt
0-1 km storm-relative helicity
102 m²/s²
0-3 km storm-relative helicity
228 m²/s²
Significant tornado parameter
0.1
Supercell composite
6.9

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Oct 24, 8:23 PM CDTMesoscale DiscussionSPCEast Carroll, Madison, Morehouse, West Carroll67 min
Oct 24, 8:46 PM CDTSevere Thunderstorm WatchSPCEast Carroll, Franklin, Madison, Morehouse, Richland, Tensas and 1 more7 hr
Oct 24, 11:35 PM CDTMesoscale DiscussionSPCEast Carroll, Franklin, Madison, West Carroll55 min
Oct 25, 1:44 AM CDTMesoscale DiscussionSPCBienville, Bossier, Caddo, Caldwell, Claiborne, De Soto and 9 more2 hr

Nearby

Severe Thunderstorm Watches in Louisiana, 2010Severe Thunderstorm Watches in Texas, 2010Every severe thunderstorm watch in 2010

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; radar from the NEXRAD Level II archive.