Alert archive / Louisiana / Tornado Watches in 2020

Tornado Watch 8

January 11, 202030 parishes in Louisiana; 7 counties in Texas

The Storm Prediction Center issued this tornado watch at Jan 11, 2020, 12:28 AM CST for 30 parishes in Louisiana; 7 counties in Texas. It was in force for 8 hr.

The area

The outline as issued.

The facts

Issued
Jan 11, 2020, 12:28 AM CST (06:28 UTC)
Expired
Jan 11, 2020, 8:00 AM CST
In force
8 hr
Issued by
the Storm Prediction Center
Largest hail expected
1.5 in
Strongest gust expected
70 kt
All 37 counties

Acadia Parish, LA, Allen Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Bienville Parish, LA, Calcasieu Parish, LA, Caldwell Parish, LA, Cameron Parish, LA, Claiborne Parish, LA, Evangeline Parish, LA, Grant Parish, LA, Iberia Parish, LA, Jackson Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Rapides Parish, LA, Red River Parish, LA, Sabine Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, St. Mary Parish, LA, Union Parish, LA, Vermilion Parish, LA, Vernon Parish, LA, Webster Parish, LA, Winn Parish, LA, Hardin County, TX, Jasper County, TX, Jefferson County, TX, Newton County, TX, Orange County, TX, Sabine County, TX, Tyler County, TX

The radar

The Ft Polk radar (KPOE), 67 km from the middle of the area, began a volume at 06:29 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
70%
One or more EF2 to EF5 tornadoes
40%
Ten or more severe wind reports
80%
One or more gusts of 65 knots or more
60%
Ten or more severe hail reports
20%
One or more hailstones of 2 inches or more
10%
Six or more combined severe hail and wind reports
90%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Jan 11, 12:50 AM CSTSevere Thunderstorm WarningLCHJasper, Tyler40 min
Jan 11, 1:00 AM CSTSevere Thunderstorm WarningSHVDe Soto, Red River, Sabine45 min
Jan 11, 1:09 AM CSTSevere Thunderstorm WarningLCHHardin, Jasper, Jefferson, Tyler21 min
Jan 11, 1:27 AM CSTTornado WarningSHVBossier, Webster28 min
Jan 11, 1:30 AM CSTSevere Thunderstorm WarningSHVBienville, Bossier, Claiborne, De Soto, Lincoln, Natchitoches and 3 more60 min
Jan 11, 1:31 AM CSTSevere Thunderstorm WarningLCHHardin, Jasper, Jefferson, Newton, Orange, Tyler59 min
Jan 11, 1:39 AM CSTSevere Thunderstorm WarningSHVDe Soto, Natchitoches, Red River, Sabine66 min
Jan 11, 1:48 AM CSTTornado WarningSHVBienville, Claiborne, Webster27 min
Jan 11, 2:16 AM CSTSevere Thunderstorm WarningLCHBeauregard, Calcasieu, Cameron, Vernon59 min
Jan 11, 2:16 AM CSTSevere Thunderstorm WarningSHVJackson, Lincoln, Ouachita, Union59 min
Jan 11, 2:34 AM CSTTornado WarningSHVUnion41 min
Jan 11, 3:05 AM CSTTornado WarningLCHBeauregard25 min
Jan 11, 3:12 AM CSTTornado WarningLCHCalcasieu33 min
Jan 11, 3:14 AM CSTSevere Thunderstorm WarningLCHAllen, Beauregard, Calcasieu, Cameron, Jefferson Davis, Rapides and 1 more61 min
Jan 11, 3:24 AM CSTSevere Thunderstorm WarningSHVCaldwell, Jackson, Lincoln, Ouachita, Union, Winn51 min
Jan 11, 3:43 AM CSTSevere Thunderstorm WarningSHVCaldwell, Grant, LaSalle, Winn62 min
Jan 11, 3:53 AM CSTTornado WarningLCHCalcasieu, Cameron, Jefferson Davis52 min
Jan 11, 4:17 AM CSTSevere Thunderstorm WarningLCHAcadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 7 more58 min
Jan 11, 4:42 AM CSTSevere Thunderstorm WarningSHVCaldwell, Grant, LaSalle33 min
Jan 11, 5:13 AM CSTSevere Thunderstorm WarningLCHAcadia, Avoyelles, Evangeline, Iberia, Lafayette, Rapides and 3 more62 min
Jan 11, 6:13 AM CSTSevere Thunderstorm WarningLCHAvoyelles, Saint Landry, Saint Martin32 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

Shreveport, LA (KSHV), launched 00:00Z, 6.5 hours before the alert went out and 143 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, Shreveport, LA at 00:00Z on 2020-01-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 703 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, Shreveport, LA at 00:00Z on 2020-01-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 379 square meters per square second.1939587897Sfc1 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
703 J/kg
Mixed-layer CIN
-35 J/kg
Mixed-layer LCL
813 m above ground
0-6 km bulk shear
50 kt
0-1 km storm-relative helicity
379 m²/s²
0-3 km storm-relative helicity
620 m²/s²
Significant tornado parameter
1.6
Supercell composite
6.1

Open this sounding in Storm Lab

The text

As transmitted.

651 
WWUS20 KWNS 110626
SEL8  
SPC WW 110626
LAZ000-TXZ000-CWZ000-111400-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 8
NWS Storm Prediction Center Norman OK
1230 AM CST Sat Jan 11 2020

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Western and central Louisiana
  Far southeast Texas
  Coastal Waters

* Effective this Saturday morning from 1230 AM until 800 AM CST.

* Primary threats include...
  A few tornadoes likely with a couple intense tornadoes possible
  Widespread damaging winds and isolated significant gusts to 80
    mph likely
  Isolated large hail events to 1.5 inches in diameter possible

SUMMARY...Elongated squall line will progress east across the Sabine
Valley through western to central Louisiana early this morning with
a couple supercells possible ahead of the line. Damaging winds and
embedded tornadoes are anticipated.

The tornado watch area is approximately along and 65 statute miles
east and west of a line from 60 miles northwest of Monroe LA to 50
miles south southeast of Lake Charles LA. 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 5...WW 6...WW 7...

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 1.5 inches. Extreme turbulence and surface wind
gusts to 70 knots. A few cumulonimbi with maximum tops to 500. Mean
storm motion vector 23045.

...Grams

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jan 10, 7:30 PM CSTMesoscale DiscussionSPCBossier, Caddo, Webster2 hr
Jan 10, 10:40 PM CSTMesoscale DiscussionSPCBienville, Bossier, Caddo, Claiborne, De Soto, Lincoln and 2 more2 hr
Jan 11, 12:21 AM CSTMesoscale DiscussionSPCAcadia, Allen, Beauregard, Calcasieu, Cameron, Evangeline and 11 more99 min
Jan 11, 1:19 AM CSTMesoscale DiscussionSPCBienville, Caldwell, Claiborne, De Soto, Jackson, Lincoln and 7 more86 min
Jan 11, 2:22 AM CSTMesoscale DiscussionSPCCatahoula, Concordia, East Carroll, Franklin, Madison, Richland and 2 more53 min
Jan 11, 2:37 AM CSTTornado WatchSPCCatahoula, Concordia, East Carroll, Franklin, Madison, Morehouse and 3 more8 hr
Jan 11, 4:31 AM CSTMesoscale DiscussionSPCAcadia, Ascension, Avoyelles, Caldwell, Catahoula, Concordia and 21 more59 min
Jan 11, 5:18 AM CSTTornado WatchSPCAscension, Assumption, East Baton Rouge, East Feliciana, Iberville, Jefferson and 16 more7 hr
Jan 11, 7:39 AM CSTMesoscale DiscussionSPCAscension, Assumption, Jefferson, Lafourche, Livingston, Orleans and 8 more96 min
Jan 10, 6:30 PM CSTMesoscale DiscussionSPCAtascosa, Bandera, Bastrop, Bexar, Blanco, Burnet and 16 more2 hr
Jan 10, 8:49 PM CSTMesoscale DiscussionSPCAngelina, Austin, Brazoria, Brazos, Burleson, Chambers and 25 more116 min
Jan 10, 9:09 PM CSTTornado WatchSPCAustin, Brazoria, Brazos, Burleson, Chambers, Colorado and 17 more5 hr
Jan 11, 7:34 AM CSTMesoscale DiscussionSPCCooke, Denton, Fannin, Grayson116 min

Nearby

Tornado Watches in Louisiana, 2020Tornado Watches in Texas, 2020Every tornado watch in 2020

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.