Alert archive / Mississippi / Tornado Watches in 2012

Tornado Watch 596

August 29, 2012Mobile County, Washington County, Alabama; 18 parishes in Louisiana; 30 counties in Mississippi

The Storm Prediction Center issued this tornado watch at Aug 29, 2012, 11:42 PM CDT for Mobile County, Washington County, Alabama; 18 parishes in Louisiana; 30 counties in Mississippi. It was in force for 8 hr.

The area

The outline as issued.

The facts

Issued
Aug 29, 2012, 11:42 PM CDT (04:42 UTC)
Expired
Aug 30, 2012, 8:00 AM CDT
In force
8 hr
Issued by
the Storm Prediction Center
All 50 counties

Mobile County, AL, Washington County, AL, Ascension Parish, LA, East Baton Rouge Parish, LA, East Feliciana 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, Washington Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Adams County, MS, Amite County, MS, Claiborne County, MS, Clarke County, MS, Copiah County, MS, Covington County, MS, Forrest County, MS, Franklin County, MS, George County, MS, Greene County, MS, Hancock County, MS, Harrison County, MS, Jackson County, MS, Jasper County, MS, Jefferson 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, Simpson County, MS, Smith County, MS, Stone County, MS, Walthall County, MS, Wayne County, MS, Wilkinson County, MS

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Aug 29, 11:45 PM CDTFlash Flood WarningLIXWashington5 hr
Aug 29, 11:54 PM CDTTornado WarningLIXHancock, Pearl River36 min
Aug 30, 12:22 AM CDTFlash Flood WarningMOBMobile, Washington6 hr
Aug 30, 12:23 AM CDTFlash Flood WarningJANJasper, Smith6 hr
Aug 30, 1:52 AM CDTFlash Flood WarningLIXSaint Tammany3 hr
Aug 30, 2:05 AM CDTFlash Flood WarningJANCopiah, Simpson6 hr
Aug 30, 2:33 AM CDTTornado WarningLIXHancock, Harrison, Pearl River27 min
Aug 30, 2:52 AM CDTFlash Flood WarningJANClarke6 hr
Aug 30, 2:55 AM CDTTornado WarningJANClarke, Jasper29 min
Aug 30, 3:21 AM CDTFlash Flood Warning EmergencyJANCovington, Forrest, Jones, Lamar6 hr
Aug 30, 3:23 AM CDTFlash Flood WarningJANJefferson Davis, Lawrence, Marion112 min
Aug 30, 3:29 AM CDTFlash Flood WarningJANFranklin, Lincoln6 hr
Aug 30, 4:17 AM CDTFlash Flood WarningLIXJackson3 hr
Aug 30, 4:31 AM CDTTornado WarningMOBWashington29 min
Aug 30, 4:58 AM CDTFlash Flood Warning EmergencyLIXSaint Tammany4 hr
Aug 30, 5:06 AM CDTTornado WarningJANClarke, Lauderdale24 min
Aug 30, 5:07 AM CDTFlash Flood WarningJANJefferson Davis, Lamar, Lawrence, Marion4 hr
Aug 30, 5:22 AM CDTTornado WarningMOBWayne23 min
Aug 30, 5:31 AM CDTTornado WarningLIXJackson29 min
Aug 30, 5:45 AM CDTTornado WarningJANClarke, Lauderdale45 min
Aug 30, 5:48 AM CDTTornado WarningMOBGreene, Wayne27 min
Aug 30, 6:28 AM CDTTornado WarningMOBWayne30 min
Aug 30, 6:43 AM CDTTornado WarningMOBChoctaw, Washington37 min
Aug 30, 6:50 AM CDTTornado WarningLIXJackson40 min
Aug 30, 6:52 AM CDTTornado WarningJANClarke, Lauderdale53 min
Aug 30, 7:07 AM CDTFlash Flood Warning EmergencyMOBGeorge6 hr
Aug 30, 7:12 AM CDTFlash Flood Warning EmergencyLIXJackson4 hr
Aug 30, 7:18 AM CDTFlash Flood WarningMOBWayne6 hr
Aug 30, 7:23 AM CDTTornado WarningMOBWayne22 min
Aug 30, 7:29 AM CDTTornado WarningLIXJackson31 min
Aug 30, 7:30 AM CDTFlash Flood WarningLIXJackson3 hr
Aug 30, 7:37 AM CDTTornado WarningJANClarke29 min
Aug 30, 7:41 AM CDTTornado WarningMOBMobile33 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

Slidell Radar S, LA (KSIL), launched 00:00Z, 4.7 hours before the alert went out and 84 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 2012-08-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 408 joules per kilogram.LCLEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°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 2012-08-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 299 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
408 J/kg
Mixed-layer CIN
0 J/kg
Mixed-layer LCL
464 m above ground
0-6 km bulk shear
55 kt
0-1 km storm-relative helicity
299 m²/s²
0-3 km storm-relative helicity
301 m²/s²
Significant tornado parameter
0.8
Supercell composite
6.3

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

273 
WWUS20 KWNS 300446
SEL6
SPC WW 300446
ALZ000-LAZ000-MSZ000-CWZ000-301300-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 596
NWS STORM PREDICTION CENTER NORMAN OK
1140 PM CDT WED AUG 29 2012

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

       FAR SOUTHWEST ALABAMA
       SOUTHEAST LOUISIANA
       SOUTHERN MISSISSIPPI
       COASTAL WATERS

EFFECTIVE THIS WEDNESDAY NIGHT AND THURSDAY MORNING FROM 1140 PM
UNTIL 800 AM CDT.

TORNADOES...THUNDERSTORM WIND GUSTS TO 70 MPH...AND DANGEROUS
LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 85 STATUTE
MILES EAST AND WEST OF A LINE FROM 50 MILES NORTH NORTHWEST OF
PINE BELT MISSISSIPPI TO 25 MILES WEST SOUTHWEST OF BOOTHVILLE
LOUISIANA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU6).

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.

OTHER WATCH INFORMATION...CONTINUE...WW 595...

DISCUSSION...STRONG LOW TO MID-TROPOSPHERIC WIND FIELD CURRENTLY
OBSERVED IN ERN SEMI-CIRCLE OF ISAAC PER JACKSON/NEW ORLEANS/MOBILE
VADS WILL BE MAINTAINED OVERNIGHT AS CENTER OF SYSTEM SLOWLY MOVES
FROM NEAR BTR TO JUST SE OF ESF THROUGH 30/12Z.  DESPITE THE TIME OF
DAY...THE OVERLAP OF A VERY MOIST/LOW LCL BOUNDARY LAYER AND STRONG
LOW-LEVEL SHEAR WILL CONTINUE TO PROMOTE SMALL-DIAMETER SUPERCELLS
WITHIN MORE PROMINENT RAIN BANDS WITH AN ATTENDANT RISK FOR BRIEF
TORNADOES.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH EXTREME
TURBULENCE AND SURFACE WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI
WITH MAXIMUM TOPS TO 400. MEAN STORM MOTION VECTOR 16050.


...MEAD

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 29, 8:21 PM CDTMesoscale DiscussionSPCBaldwin, Mobile, Washington84 min
Aug 29, 11:06 PM CDTMesoscale DiscussionSPCBaldwin, Mobile, Washington84 min
Aug 30, 3:18 AM CDTMesoscale DiscussionSPCBaldwin, Butler, Choctaw, Clarke, Coffee, Conecuh and 7 more117 min
Aug 30, 6:33 AM CDTMesoscale DiscussionSPCBaldwin, Butler, Choctaw, Clarke, Coffee, Conecuh and 13 more117 min
Aug 30, 7:13 AM CDTTornado WatchSPCAutauga, Baldwin, Butler, Choctaw, Clarke, Conecuh and 15 more9 hr
Aug 30, 12:57 PM CDTMesoscale DiscussionSPCBaldwin, Butler, Choctaw, Clarke, Conecuh, Dallas and 8 more93 min
Aug 30, 3:56 PM CDTTornado WatchSPCChoctaw, Greene, Sumter, Washington6 hr

Nearby

Tornado Watches in Mississippi, 2012Tornado Watches in Louisiana, 2012Tornado Watches in Alabama, 2012Every tornado watch in 2012

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.