Alert archive / Louisiana / Tornado Watches in 2015

Tornado Watch 219

May 25, 201538 parishes in Louisiana; 20 counties in Mississippi

The Storm Prediction Center issued this tornado watch at May 25, 2015, 10:37 PM CDT for 38 parishes in Louisiana; 20 counties in Mississippi. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
May 25, 2015, 10:37 PM CDT (03:37 UTC)
Expired
May 26, 2015, 5:00 AM CDT
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
60 kt
All 58 counties

Ascension Parish, LA, Assumption Parish, LA, Avoyelles Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, East Baton Rouge Parish, LA, East Carroll Parish, LA, East Feliciana Parish, LA, Franklin Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jefferson Parish, LA, Lafayette Parish, LA, Lafourche Parish, LA, Livingston Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Orleans Parish, LA, Plaquemines Parish, LA, Pointe Coupee Parish, LA, Richland 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, Tensas Parish, LA, Terrebonne Parish, LA, Vermilion Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, West Carroll Parish, LA, West Feliciana Parish, LA, Adams County, MS, Amite County, MS, Claiborne County, MS, Copiah County, MS, Franklin County, MS, Hancock County, MS, Harrison County, MS, Issaquena County, MS, Jackson County, MS, Jefferson County, MS, Jefferson Davis County, MS, Lamar County, MS, Lawrence County, MS, Lincoln County, MS, Marion County, MS, Pearl River County, MS, Pike County, MS, Walthall County, MS, Warren 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
20%
Ten or more severe wind reports
60%
One or more gusts of 65 knots or more
10%
Ten or more severe hail reports
20%
One or more hailstones of 2 inches or more
5%
Six or more combined severe hail and wind reports
90%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
May 25, 10:40 PM CDTSevere Thunderstorm WarningJANFranklin, Morehouse, Richland, West Carroll65 min
May 25, 11:15 PM CDTSevere Thunderstorm WarningJANCatahoula, Franklin45 min
May 25, 11:29 PM CDTSevere Thunderstorm WarningLCHAcadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 4 more91 min
May 25, 11:36 PM CDTSevere Thunderstorm WarningJANMadison, Tensas39 min
May 25, 11:42 PM CDTSevere Thunderstorm WarningJANConcordia48 min
May 26, 12:12 AM CDTSevere Thunderstorm WarningJANMadison, Tensas78 min
May 26, 12:16 AM CDTSevere Thunderstorm WarningJANAdams, Franklin, Jefferson59 min
May 26, 12:22 AM CDTFlash Flood WarningJANConcordia3 hr
May 26, 12:23 AM CDTSevere Thunderstorm WarningLIXIberville, Pointe Coupee52 min
May 26, 12:54 AM CDTSevere Thunderstorm WarningJANClaiborne, Copiah, Hinds, Jefferson51 min
May 26, 1:08 AM CDTSevere Thunderstorm WarningLIXEast Feliciana, West Feliciana52 min
May 26, 1:11 AM CDTTornado WarningLIXJefferson34 min
May 26, 1:30 AM CDTTornado WarningLIXAmite, Wilkinson30 min
May 26, 1:59 AM CDTSevere Thunderstorm WarningLIXEast Baton Rouge, East Feliciana, Livingston, Saint Helena, Tangipahoa46 min
May 26, 2:45 AM CDTSevere Thunderstorm WarningLIXLivingston, Saint Helena, Saint Tammany, Tangipahoa, Washington45 min
May 26, 4:01 AM CDTSevere Thunderstorm WarningLIXJefferson, Orleans, Plaquemines, Saint Bernard, Saint Charles44 min
May 26, 4:23 AM CDTSevere Thunderstorm WarningLIXOrleans, Saint Tammany37 min
May 26, 4:43 AM CDTSevere Thunderstorm WarningLIXJefferson, Orleans, Plaquemines, Saint Bernard47 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, 3.6 hours before the alert went out and 67 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 2015-05-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 693 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 00:00Z on 2015-05-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 37 square meters per square second.193958Sfc1 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
693 J/kg
Mixed-layer CIN
-75 J/kg
Mixed-layer LCL
967 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
37 m²/s²
0-3 km storm-relative helicity
77 m²/s²
Significant tornado parameter
0.1
Supercell composite
0.9

Open this sounding in Storm Lab

The text

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

089 
WWUS20 KWNS 260335
SEL9  
SPC WW 260335
LAZ000-MSZ000-CWZ000-261000-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 219
NWS STORM PREDICTION CENTER NORMAN OK
1035 PM CDT MON MAY 25 2015

THE NWS STORM PREDICTION CENTER HAS ISSUED A

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

* EFFECTIVE THIS MONDAY NIGHT AND TUESDAY MORNING FROM 1035 PM
  UNTIL 500 AM CDT.

* PRIMARY THREATS INCLUDE...
  A COUPLE TORNADOES POSSIBLE
  SCATTERED DAMAGING WIND GUSTS TO 70 MPH LIKELY
  ISOLATED LARGE HAIL EVENTS TO 1 INCH IN DIAMETER POSSIBLE

SUMMARY...CENTRAL LA SQUALL LINE SHOULD CONTINUE ESE WITH A
CONTINUED RISK FOR LOCALLY DAMAGING WIND AND ISOLATED TORNADOES.  AN
ISOLATED TORNADO AND DAMAGING WIND RISK ALSO MAY ACCOMPANY ISOLATED
STORMS FORMING AHEAD OF LINE OVER SE LA/SW MS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 110 STATUTE
MILES NORTH AND SOUTH OF A LINE FROM 45 MILES SOUTH SOUTHEAST OF
GULFPORT MISSISSIPPI TO 55 MILES WEST SOUTHWEST OF NATCHEZ
MISSISSIPPI.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU9).

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 214...WW 215...WW
216...WW 217...WW 218...

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 600.
MEAN STORM MOTION VECTOR 23025.


...CORFIDI

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 25, 8:05 PM CDTMesoscale DiscussionSPCAcadia, Allen, Beauregard, Bienville, Bossier, Caddo and 17 more85 min
May 25, 10:14 PM CDTMesoscale DiscussionSPCAcadia, Ascension, Assumption, Avoyelles, Catahoula, Concordia and 22 more91 min
May 25, 11:13 PM CDTMesoscale DiscussionSPCAllen, Beauregard, Calcasieu, Cameron, Evangeline, Jefferson Davis and 1 more92 min
May 25, 11:57 PM CDTMesoscale DiscussionSPCAcadia, Ascension, Assumption, Avoyelles, Concordia, East Baton Rouge and 27 more93 min
May 26, 3:50 AM CDTMesoscale DiscussionSPCJefferson, Lafourche, Orleans, Plaquemines, Saint Bernard, Saint Charles and 4 more85 min
May 26, 6:22 PM CDTMesoscale DiscussionSPCBienville, Bossier, Caddo, Caldwell, Catahoula, Claiborne and 15 more83 min
May 25, 8:52 PM CDTMesoscale DiscussionSPCBolivar, Coahoma, DeSoto, Quitman, Tate, Tunica83 min

Nearby

Tornado Watches in Louisiana, 2015Tornado Watches in Mississippi, 2015Every 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.