Alert archive / Louisiana / Tornado Watches in 2014

Tornado Watch 550

November 16, 201425 parishes in Louisiana

The Storm Prediction Center issued this tornado watch at Nov 16, 2014, 2:45 PM CST for 25 parishes in Louisiana. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued: Nov 16, 2014, 2:45 PM CST (20:45 UTC)
Expired: Nov 16, 2014, 10:00 PM CST
In force: 7 hr
Issued by: the Storm Prediction Center
Largest hail expected: 0.5 in
Strongest gust expected: 60 kt

All 25 counties

Acadia Parish, LA, Ascension Parish, LA, Assumption Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Lafayette Parish, LA, Lafourche Parish, LA, Livingston Parish, LA, Pointe Coupee 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

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: 40%
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: 60%

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
Nov 16, 3:15 PM CST	Severe Thunderstorm Warning	LIX	East Baton Rouge, East Feliciana, Iberville, Pointe Coupee, West Baton Rouge	45 min
Nov 16, 4:09 PM CST	Severe Thunderstorm Warning	LCH	Vermilion	66 min
Nov 16, 8:06 PM CST	Tornado Warning	LIX	Livingston, Saint Helena, Tangipahoa	24 min
Nov 16, 8:28 PM CST	Tornado Warning	LIX	Livingston, Saint Helena, Tangipahoa	47 min
Nov 16, 9:15 PM CST	Tornado Warning	LIX	Tangipahoa, Washington	30 min
Nov 16, 9:16 PM CST	Tornado Warning	LIX	East Baton Rouge, Livingston	29 min
Nov 16, 9:43 PM CST	Tornado Warning	LIX	Washington	47 min
Nov 16, 9:46 PM CST	Severe Thunderstorm Warning	LIX	Livingston, Tangipahoa	44 min
Nov 16, 9:58 PM CST	Tornado Warning	LIX	Livingston, Tangipahoa	32 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, 8.8 hours before the alert went out and 161 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 812 m above ground
0-6 km bulk shear: 50 kt
0-1 km storm-relative helicity: 178 m²/s²
0-3 km storm-relative helicity: 191 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.

295 
WWUS20 KWNS 162050
SEL0  
SPC WW 162050
LAZ000-CWZ000-170400-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 550
NWS STORM PREDICTION CENTER NORMAN OK
245 PM CST SUN NOV 16 2014

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* TORNADO WATCH FOR PORTIONS OF 
  SOUTHERN AND SOUTHEASTERN LOUISIANA
  COASTAL WATERS

* EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 245 PM UNTIL
  1000 PM CST.

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

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 65 STATUTE
MILES EAST AND WEST OF A LINE FROM 40 MILES NORTHEAST OF BATON
ROUGE LOUISIANA TO 40 MILES SOUTH SOUTHEAST OF INTRACOASTAL CITY
LOUISIANA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU0).

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.

&&

DISCUSSION...BROKEN SQLN WITH SCTD EMBEDDED SUPERCELLS/LOW-AMPLITUDE
LEWPS ALONG SSW/NNE-ORIENTED SFC TROUGH ON WRN BORDER OF WW EXPECTED
TO EDGE SLOWLY E ACROSS SRN LA THIS EVE AS A WEAK SFC WAVE EVOLVES
NEAR BATON ROUGE. LATEST SFC DATA INDICATE THAT RICHER LOW-LVL
MOISTURE WILL CONTINUE TO MOVE ASHORE E OF THE TROUGH...WITH SFC
DEWPOINTS RISING INTO THE MID/UPR 60S F. AT THE SAME TIME...GRADUAL
TIGHTENING OF UPR HEIGHT GRADIENT/WEAK HEIGHT FALLS WILL SUPPORT A
MODEST INCREASE IN 40-50 KT WSWLY DEEP SHEAR. THIS SETUP MAY YIELD 
SPORADIC STORMS CAPABLE OF LOCALLY DMGG WIND AND A TORNADO OR
TWO...ESPECIALLY ALONG AND S OF I-10/12.

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
450. MEAN STORM MOTION VECTOR 24030.


...CORFIDI

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Nov 16, 11:47 AM CST	Mesoscale Discussion	SPC	Acadia, Ascension, Assumption, Cameron, East Baton Rouge, Iberia and 11 more	118 min
Nov 16, 5:50 PM CST	Mesoscale Discussion	SPC	Jefferson, Orleans, Plaquemines, Saint Bernard, Saint Tammany	85 min

Nearby

Tornado Watches in Louisiana, 2014 Every tornado watch in 2014

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.