Alert archive / Louisiana / Severe Thunderstorm Watches in 2016

Severe Thunderstorm Watch 2

January 8, 201625 parishes in Louisiana

The Storm Prediction Center issued this severe thunderstorm watch at Jan 8, 2016, 10:44 PM CST for 25 parishes in Louisiana. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued: Jan 8, 2016, 10:44 PM CST (04:44 UTC)
Expired: Jan 9, 2016, 6:00 AM CST
In force: 7 hr
Issued by: the Storm Prediction Center
Largest hail expected: 1.5 in
Strongest gust expected: 60 kt

All 25 counties

Acadia Parish, LA, Allen Parish, LA, Ascension Parish, LA, Assumption Parish, LA, Avoyelles Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, East Baton Rouge Parish, LA, Evangeline Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, Lafourche Parish, LA, Pointe Coupee Parish, LA, Rapides Parish, LA, Saint Charles Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, St. Mary Parish, LA, Terrebonne Parish, LA, Vermilion Parish, LA, West Baton Rouge Parish, LA

The radar

The Lake Charles radar (KLCH), 109 km from the middle of the area, began a volume at 04:48 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: 2%
Ten or more severe wind reports: 30%
One or more gusts of 65 knots or more: 10%
Ten or more severe hail reports: 30%
One or more hailstones of 2 inches or more: 10%
Six or more combined severe hail and wind reports: 60%

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
Jan 8, 11:25 PM CST	Tornado Warning	LCH	Avoyelles	21 min
Jan 8, 11:40 PM CST	Severe Thunderstorm Warning	LCH	Acadia, Jefferson Davis	23 min
Jan 9, 12:16 AM CST	Severe Thunderstorm Warning	LCH	Lafayette, Saint Martin	44 min
Jan 9, 12:49 AM CST	Tornado Warning	LCH	Saint Martin	26 min
Jan 9, 1:06 AM CST	Severe Thunderstorm Warning	LIX	Iberville	24 min
Jan 9, 1:29 AM CST	Severe Thunderstorm Warning	LIX	Iberville, West Baton Rouge	31 min
Jan 9, 5:03 AM CST	Severe Thunderstorm Warning	LIX	Lafourche, Terrebonne	27 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

Lake Charles Mun, LA (KLCH), launched 00:00Z, 4.7 hours before the alert went out and 108 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: 1021 J/kg
Mixed-layer CIN: -58 J/kg
Mixed-layer LCL: 665 m above ground
0-6 km bulk shear: 71 kt
0-1 km storm-relative helicity: 201 m²/s²
0-3 km storm-relative helicity: 240 m²/s²
Significant tornado parameter: 1.1
Supercell composite: 7.8

Open this sounding in Storm Lab

The text

As transmitted.

394 
WWUS20 KWNS 090443
SEL2  
SPC WW 090443
LAZ000-CWZ000-091200-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 2
NWS STORM PREDICTION CENTER NORMAN OK
1045 PM CST FRI JAN 8 2016

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF 
  SOUTHWEST AND SOUTH-CENTRAL LOUISIANA
  COASTAL WATERS

* EFFECTIVE THIS FRIDAY NIGHT AND SATURDAY MORNING FROM 1045 PM
  UNTIL 600 AM CST.

* PRIMARY THREATS INCLUDE...
  ISOLATED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE
  ISOLATED LARGE HAIL EVENTS TO 1.5 INCHES IN DIAMETER POSSIBLE
  A TORNADO OR TWO POSSIBLE

SUMMARY...THUNDERSTORMS ARE EXPECTED TO SPREAD FROM WEST TO EAST
ACROSS THE WATCH AREA LATE TONIGHT INTO EARLY SATURDAY MORNING. 
LARGE HAIL WILL BE THE PRIMARY HAZARD...THOUGH A BRIEF TORNADO OR
TWO AND/OR LOCALLY DAMAGING WINDS WILL BE POSSIBLE WITH STORMS NEAR
THE IMMEDIATE COAST.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 45
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 5 MILES WEST
SOUTHWEST OF LAKE CHARLES LOUISIANA TO 25 MILES EAST SOUTHEAST OF
HOUMA LOUISIANA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU2).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR 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. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 1...

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 23035.


...MEAD

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jan 8, 6:31 PM CST	Mesoscale Discussion	SPC	Acadia, Allen, Beauregard, Caddo, Calcasieu, Cameron and 7 more	119 min
Jan 8, 9:52 PM CST	Mesoscale Discussion	SPC	Acadia, Allen, Ascension, Assumption, Beauregard, Calcasieu and 13 more	83 min
Jan 9, 2:52 AM CST	Mesoscale Discussion	SPC	Acadia, Ascension, Assumption, Cameron, East Baton Rouge, Evangeline and 15 more	113 min
Jan 9, 5:28 AM CST	Mesoscale Discussion	SPC	Jefferson, Lafourche, Plaquemines	62 min

Nearby

Severe Thunderstorm Watches in Louisiana, 2016 Every severe thunderstorm watch in 2016

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.