Alert archive / Louisiana / Tornado Watches in 2015

Tornado Watch 528

October 31, 201533 parishes in Louisiana; 29 counties in Mississippi

The Storm Prediction Center issued this tornado watch at Oct 31, 2015, 11:45 AM CDT for 33 parishes in Louisiana; 29 counties in Mississippi. It was in force for 8 hr.

The area

The outline as issued.

The facts

Issued: Oct 31, 2015, 11:45 AM CDT (16:45 UTC)
Expired: Oct 31, 2015, 7:34 PM CDT
In force: 8 hr
Issued by: the Storm Prediction Center
Largest hail expected: 0.5 in
Strongest gust expected: 60 kt

All 62 counties

Acadia Parish, LA, Ascension Parish, LA, Assumption Parish, LA, Avoyelles Parish, LA, Cameron Parish, LA, Concordia Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Evangeline Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jefferson Parish, LA, Lafayette Parish, LA, Lafourche Parish, LA, Livingston Parish, LA, Orleans Parish, LA, Plaquemines Parish, LA, Pointe Coupee 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 Landry Parish, LA, Saint Martin Parish, LA, Saint Tammany Parish, LA, St. Mary Parish, LA, Tangipahoa Parish, LA, Terrebonne Parish, LA, Vermilion 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, 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

What SPC expected

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

Two or more tornadoes: 30%
One or more EF2 to EF5 tornadoes: 10%
Ten or more severe wind reports: 30%
One or more gusts of 65 knots or more: 5%
Ten or more severe hail reports: 5%
One or more hailstones of 2 inches or more: 5%
Six or more combined severe hail and wind reports: 50%

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
Oct 31, 11:48 AM CDT	Tornado Warning	JAN	Catahoula, Concordia	27 min
Oct 31, 12:28 PM CDT	Tornado Warning	LIX	Ascension, Livingston	32 min
Oct 31, 12:39 PM CDT	Tornado Warning	LIX	Pointe Coupee	36 min
Oct 31, 12:42 PM CDT	Flash Flood Warning	LCH	Beauregard, Calcasieu, Cameron, Rapides, Vernon	6 hr
Oct 31, 12:56 PM CDT	Tornado Warning	JAN	Franklin	49 min
Oct 31, 1:21 PM CDT	Tornado Warning	LIX	Livingston	24 min
Oct 31, 1:33 PM CDT	Tornado Warning	LIX	Tangipahoa	42 min
Oct 31, 1:35 PM CDT	Tornado Warning	LIX	Saint Tammany, Washington	40 min
Oct 31, 1:38 PM CDT	Severe Thunderstorm Warning	JAN	Franklin, Lincoln	52 min
Oct 31, 1:43 PM CDT	Severe Thunderstorm Warning	LIX	East Feliciana	32 min
Oct 31, 1:55 PM CDT	Tornado Warning Tornado observed	LIX	Tangipahoa	35 min
Oct 31, 2:03 PM CDT	Tornado Warning	LIX	East Baton Rouge, Livingston, Saint Helena	27 min
Oct 31, 2:06 PM CDT	Tornado Warning	LIX	Amite, Pike	24 min
Oct 31, 2:12 PM CDT	Tornado Warning	JAN	Lawrence, Lincoln	25 min
Oct 31, 2:22 PM CDT	Tornado Warning	LIX	Saint Helena	23 min
Oct 31, 2:35 PM CDT	Severe Thunderstorm Warning	JAN	Jefferson Davis, Lawrence, Lincoln	40 min
Oct 31, 2:36 PM CDT	Tornado Warning	LIX	Pike, Walthall	39 min
Oct 31, 2:45 PM CDT	Severe Thunderstorm Warning	LIX	Tangipahoa, Washington	60 min
Oct 31, 3:05 PM CDT	Tornado Warning	LIX	Tangipahoa	25 min
Oct 31, 3:10 PM CDT	Severe Thunderstorm Warning	JAN	Marion	51 min
Oct 31, 3:12 PM CDT	Tornado Warning	JAN	Marion	40 min
Oct 31, 3:23 PM CDT	Severe Thunderstorm Warning	LIX	Washington	37 min
Oct 31, 3:29 PM CDT	Tornado Warning	LIX	Saint Tammany, Washington	31 min
Oct 31, 3:36 PM CDT	Severe Thunderstorm Warning	JAN	Jasper, Jones	39 min
Oct 31, 3:49 PM CDT	Severe Thunderstorm Warning	JAN	Covington, Forrest, Jefferson Davis, Lamar	53 min
Oct 31, 4:07 PM CDT	Severe Thunderstorm Warning	JAN	Forrest, Jones, Lamar	38 min
Oct 31, 4:07 PM CDT	Severe Thunderstorm Warning	LIX	Pearl River	23 min
Oct 31, 4:13 PM CDT	Tornado Warning	LIX	Pearl River	32 min
Oct 31, 4:14 PM CDT	Severe Thunderstorm Warning	JAN	Jasper, Jones	31 min
Oct 31, 4:16 PM CDT	Tornado Warning	JAN	Jones	29 min
Oct 31, 4:19 PM CDT	Tornado Warning	JAN	Forrest, Lamar	29 min
Oct 31, 4:35 PM CDT	Severe Thunderstorm Warning	MOB	Wayne	25 min
Oct 31, 4:41 PM CDT	Severe Thunderstorm Warning	MOB	Greene, Perry, Wayne	49 min
Oct 31, 4:44 PM CDT	Tornado Warning	LIX	Pearl River	31 min
Oct 31, 4:46 PM CDT	Severe Thunderstorm Warning	JAN	Clarke, Jasper, Jones	44 min
Oct 31, 4:47 PM CDT	Flash Flood Warning	JAN	Jones	118 min
Oct 31, 4:52 PM CDT	Severe Thunderstorm Warning	MOB	George, Greene, Perry, Stone	38 min
Oct 31, 4:53 PM CDT	Severe Thunderstorm Warning	MOB	Wayne	37 min
Oct 31, 5:04 PM CDT	Tornado Warning	MOB	Wayne	31 min
Oct 31, 5:14 PM CDT	Flash Flood Warning	JAN	Clarke	2 hr
Oct 31, 5:21 PM CDT	Severe Thunderstorm Warning	JAN	Clarke, Lauderdale	24 min
Oct 31, 5:23 PM CDT	Severe Thunderstorm Warning	MOB	Wayne	52 min
Oct 31, 5:26 PM CDT	Severe Thunderstorm Warning	MOB	Greene, Wayne	1 min
Oct 31, 5:28 PM CDT	Severe Thunderstorm Warning	MOB	Greene, Perry, Wayne	47 min
Oct 31, 5:31 PM CDT	Severe Thunderstorm Warning	MOB	George, Greene, Perry, Stone	44 min
Oct 31, 6:11 PM CDT	Severe Thunderstorm Warning	MOB	Greene	49 min
Oct 31, 6:12 PM CDT	Severe Thunderstorm Warning	MOB	George, Greene	48 min
Oct 31, 6:31 PM CDT	Tornado Warning	MOB	George	44 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 12:00Z, 4.8 hours before the alert went out and 134 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 847 m above ground
0-6 km bulk shear: 51 kt
0-1 km storm-relative helicity: 292 m²/s²
0-3 km storm-relative helicity: 361 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

540 
WWUS20 KWNS 311642
SEL8  
SPC WW 311642
LAZ000-MSZ000-CWZ000-010000-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 528
NWS STORM PREDICTION CENTER NORMAN OK
1140 AM CDT SAT OCT 31 2015

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* TORNADO WATCH FOR PORTIONS OF 
  SOUTHERN AND EASTERN LOUISIANA
  SOUTHERN MISSISSIPPI
  COASTAL WATERS

* EFFECTIVE THIS SATURDAY MORNING AND EVENING FROM 1140 AM UNTIL
  700 PM CDT.

* PRIMARY THREATS INCLUDE...
  A COUPLE TORNADOES POSSIBLE
  ISOLATED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE

SUMMARY...S CENTRAL LOUISIANA SQUALL LINE EXPECTED TO CONTINUE
SLOWLY EASTWARD...WITH ADDITIONAL ISOLATED STORMS POSSIBLY FORMING
AHEAD OF THE LINE IN SE LOUISIANA. THE STORMS MAY POSE AN OCCASIONAL
RISK FOR TORNADOES IN ADDITION TO LOCALLY DAMAGING WIND.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 90 STATUTE
MILES EAST AND WEST OF A LINE FROM 50 MILES NORTHWEST OF PINE
BELT MISSISSIPPI TO 50 MILES SOUTHEAST OF INTRACOASTAL CITY
LOUISIANA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU8).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 527...

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 0.5 INCH. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 22040.


...CORFIDI

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Oct 31, 6:54 AM CDT	Tornado Watch	SPC	Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 10 more	5 hr
Oct 31, 10:03 AM CDT	Mesoscale Discussion	SPC	Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 8 more	57 min
Oct 31, 11:01 AM CDT	Mesoscale Discussion	SPC	Ascension, Assumption, Avoyelles, East Baton Rouge, East Feliciana, Iberia and 18 more	89 min
Oct 31, 1:35 PM CDT	Mesoscale Discussion	SPC	Acadia, Ascension, Assumption, Concordia, East Baton Rouge, East Feliciana and 22 more	55 min
Oct 31, 3:36 PM CDT	Mesoscale Discussion	SPC	Acadia, Ascension, Assumption, Concordia, East Baton Rouge, East Feliciana and 22 more	54 min
Oct 31, 5:42 PM CDT	Mesoscale Discussion	SPC	Acadia, Ascension, Assumption, Concordia, East Baton Rouge, East Feliciana and 22 more	93 min

Nearby

Tornado Watches in Louisiana, 2015 Tornado Watches in Mississippi, 2015 Every tornado watch in 2015

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.