Alert archive / Louisiana / Tornado Watches in 2019

Tornado Watch 697

November 30, 201917 counties in Arkansas; 20 parishes in Louisiana; 13 counties in Texas

The Storm Prediction Center issued this tornado watch at Nov 30, 2019, 11:38 AM CST for 17 counties in Arkansas; 20 parishes in Louisiana; 13 counties in Texas. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Nov 30, 2019, 11:38 AM CST (17:38 UTC)
Expired
Nov 30, 2019, 7:00 PM CST
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt
All 50 counties

Arkansas County, AR, Ashley County, AR, Bradley County, AR, Calhoun County, AR, Chicot County, AR, Cleveland County, AR, Columbia County, AR, Dallas County, AR, Desha County, AR, Drew County, AR, Grant County, AR, Jefferson County, AR, Lafayette County, AR, Lincoln County, AR, Nevada County, AR, Ouachita County, AR, Union County, AR, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Caldwell Parish, LA, Claiborne Parish, LA, De Soto Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Red River Parish, LA, Richland Parish, LA, Sabine Parish, LA, Union Parish, LA, Webster Parish, LA, West Carroll Parish, LA, Winn Parish, LA, Angelina County, TX, Cherokee County, TX, Gregg County, TX, Harrison County, TX, Marion County, TX, Nacogdoches County, TX, Panola County, TX, Rusk County, TX, Sabine County, TX, San Augustine County, TX, Shelby County, TX, Smith County, TX, Upshur County, TX

The radar

The Shreveport radar (KSHV), 38 km from the middle of the area, began a volume at 17:37 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
50%
One or more gusts of 65 knots or more
20%
Ten or more severe hail reports
40%
One or more hailstones of 2 inches or more
30%
Six or more combined severe hail and wind reports
80%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Nov 30, 12:21 PM CSTSevere Thunderstorm WarningLZKBradley, Calhoun, Cleveland, Drew, Lincoln24 min
Nov 30, 2:23 PM CSTSevere Thunderstorm WarningSHVDe Soto, Natchitoches, Red River, Sabine52 min
Nov 30, 2:56 PM CSTSevere Thunderstorm WarningSHVJackson, Lincoln, Ouachita, Union49 min
Nov 30, 3:24 PM CSTSevere Thunderstorm WarningSHVJackson, Winn51 min
Nov 30, 3:57 PM CSTSevere Thunderstorm WarningSHVCaldwell, Ouachita48 min
Nov 30, 3:59 PM CSTSevere Thunderstorm WarningLZKDesha, Drew31 min
Nov 30, 4:09 PM CSTSevere Thunderstorm WarningJANFranklin, Richland51 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 12:00Z, 5.6 hours before the alert went out and 30 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 12:00Z on 2019-11-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 320 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 12:00Z on 2019-11-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 487 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
320 J/kg
Mixed-layer CIN
-311 J/kg
Mixed-layer LCL
606 m above ground
0-6 km bulk shear
54 kt
0-1 km storm-relative helicity
487 m²/s²
0-3 km storm-relative helicity
527 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.4

Open this sounding in Storm Lab

The text

As transmitted.

948 
WWUS20 KWNS 301735
SEL7  
SPC WW 301735
ARZ000-LAZ000-TXZ000-010100-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 697
NWS Storm Prediction Center Norman OK
1235 PM CDT Sat Nov 30 2019

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Southern Arkansas
  Northern Louisiana
  East Texas

* Effective this Saturday afternoon and evening from 1235 PM
  until 800 PM CDT.

* Primary threats include...
  A couple tornadoes possible
  Scattered large hail and isolated very large hail events to 2
    inches in diameter possible
  Scattered damaging wind gusts to 70 mph possible

SUMMARY...Multiple bands/corridors of storms will increase across
the region, initially across far east Texas, southern Arkansas, and
northwest Louisiana early this afternoon, and by mid-afternoon
across additional parts of northern Louisiana. Conditions are
favorable for supercells/organized line segments capable of damaging
winds/hail and a couple of tornadoes.

The tornado watch area is approximately along and 80 statute miles
east and west of a line from 65 miles west southwest of Natchitoches
LA to 25 miles north of Monticello AR. For a complete depiction of
the watch see the associated watch outline update (WOUS64 KWNS
WOU7).

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.

&&

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 2 inches. Extreme turbulence and surface wind
gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean
storm motion vector 24040.

...Guyer

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Nov 30, 4:45 AM CSTMesoscale DiscussionSPCPolk2 hr
Nov 30, 9:46 AM CSTMesoscale DiscussionSPCAshley, Bradley, Calhoun, Clark, Cleveland, Columbia and 12 more3 hr
Nov 30, 2:10 PM CSTMesoscale DiscussionSPCAshley, Bradley, Chicot, Desha, Drew, Union2 hr
Nov 30, 2:31 PM CSTMesoscale DiscussionSPCLee, Phillips59 min
Nov 30, 3:54 PM CSTTornado WatchSPCCatahoula, Concordia, East Carroll, Franklin, Madison, Tensas7 hr

Nearby

Tornado Watches in Louisiana, 2019Tornado Watches in Arkansas, 2019Tornado Watches in Texas, 2019Every tornado watch in 2019

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.