Alert archive / Louisiana / Tornado Watches in 2017

Tornado Watch 33

February 14, 201711 parishes in Louisiana; 11 counties in Texas

The Storm Prediction Center issued this tornado watch at Feb 14, 2017, 9:38 AM CST for 11 parishes in Louisiana; 11 counties in Texas. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Feb 14, 2017, 9:38 AM CST (15:38 UTC)
Expired
Feb 14, 2017, 3:00 PM CST
In force
5 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
60 kt
All 22 counties

Acadia Parish, LA, Allen Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, Evangeline Parish, LA, Jefferson Davis Parish, LA, Natchitoches Parish, LA, Sabine Parish, LA, Vermilion Parish, LA, Vernon Parish, LA, Angelina County, TX, Hardin County, TX, Jasper County, TX, Jefferson County, TX, Nacogdoches County, TX, Newton County, TX, Orange County, TX, Sabine County, TX, San Augustine County, TX, Shelby County, TX, Tyler County, TX

The radar

The Lake Charles radar (KLCH), 82 km from the middle of the area, began a volume at 15:40 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
40%
One or more EF2 to EF5 tornadoes
20%
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%

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 12:00Z, 3.6 hours before the alert went out and 83 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, Lake Charles Mun, LA at 12:00Z on 2017-02-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 22 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, Lake Charles Mun, LA at 12:00Z on 2017-02-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 137 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
22 J/kg
Mixed-layer CIN
-294 J/kg
Mixed-layer LCL
644 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
137 m²/s²
0-3 km storm-relative helicity
227 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

173 
WWUS20 KWNS 141535
SEL3  
SPC WW 141535
LAZ000-TXZ000-CWZ000-142100-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 33
NWS Storm Prediction Center Norman OK
940 AM CST Tue Feb 14 2017

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Southwest Louisiana
  Southeast Texas
  Coastal Waters

* Effective this Tuesday morning and afternoon from 940 AM until
  300 PM CST.

* Primary threats include...
  A couple tornadoes possible
  Isolated damaging wind gusts to 70 mph possible
  Isolated large hail events to 1 inch in diameter possible

SUMMARY...A line of strong to severe thunderstorms will track across
the watch area late this morning and early afternoon, posing a risk
of damaging winds and a tornado or two.

The tornado watch area is approximately along and 90 statute miles
north and south of a line from 50 miles northwest of Port Arthur TX
to 50 miles east northeast of Lake Charles LA. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU3).

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 32...

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 450. Mean
storm motion vector 25030.

...Hart

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Feb 14, 7:21 AM CSTMesoscale DiscussionSPCAcadia, Allen, Beauregard, Calcasieu, Cameron, Evangeline and 3 more114 min
Feb 14, 11:15 AM CSTMesoscale DiscussionSPCAcadia, Allen, Beauregard, Calcasieu, Cameron, Jefferson Davis and 2 more90 min
Feb 14, 2:02 PM CSTMesoscale DiscussionSPCAscension, Assumption, Avoyelles, Catahoula, Concordia, East Baton Rouge and 20 more2 hr
Feb 13, 8:24 PM CSTMesoscale DiscussionSPCBandera, Kerr, Llano, McCulloch, Mason, San Saba96 min
Feb 14, 3:57 AM CSTMesoscale DiscussionSPCAtascosa, Austin, Bee, Bexar, Brazoria, Colorado and 16 more3 hr
Feb 14, 5:09 AM CSTTornado WatchSPCAransas, Austin, Bee, Brazoria, Calhoun, Chambers and 24 more6 hr

Nearby

Tornado Watches in Louisiana, 2017Tornado Watches in Texas, 2017Every tornado watch in 2017

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.