Alert archive / Louisiana / Tornado Watches in 2020

Tornado Watch 453

August 26, 202038 parishes in Louisiana; Adams County, Wilkinson County, Mississippi; 9 counties in Texas

The Storm Prediction Center issued this tornado watch at Aug 26, 2020, 9:03 PM CDT for 38 parishes in Louisiana; Adams County, Wilkinson County, Mississippi; 9 counties in Texas. It was in force for 11 hr.

The area

The outline as issued.

The facts

Issued
Aug 26, 2020, 9:03 PM CDT (02:03 UTC)
Expired
Aug 27, 2020, 8:00 AM CDT
In force
11 hr
Issued by
the Storm Prediction Center
Strongest gust expected
60 kt
All 49 counties

Acadia Parish, LA, Allen Parish, LA, Ascension Parish, LA, Assumption Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Evangeline Parish, LA, Grant Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jefferson Davis Parish, LA, Jefferson Parish, LA, Lafayette Parish, LA, Lafourche Parish, LA, LaSalle Parish, LA, Livingston Parish, LA, Natchitoches Parish, LA, Pointe Coupee Parish, LA, Rapides Parish, LA, Sabine 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, Vernon Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Winn Parish, LA, Adams County, MS, Wilkinson County, MS, Hardin County, TX, Jasper County, TX, Jefferson County, TX, Newton County, TX, Orange County, TX, Sabine County, TX, San Augustine County, TX, Shelby County, TX, Tyler County, TX

The radar

The Ft Polk radar (KPOE), 93 km from the middle of the area, began a volume at 02:03 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
60%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
5%
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
20%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Aug 26, 9:10 PM CDTTornado WarningLCHCameron35 min
Aug 26, 9:14 PM CDTTornado WarningLCHCameron, Vermilion31 min
Aug 26, 9:40 PM CDTTornado Warning Tornado observedLCHCalcasieu, Cameron, Jefferson Davis, Vermilion35 min
Aug 26, 9:42 PM CDTTornado WarningLCHCameron, Jefferson Davis, Vermilion33 min
Aug 26, 10:07 PM CDTTornado WarningLCHCameron38 min
Aug 26, 10:12 PM CDTTornado WarningLCHCalcasieu, Cameron, Jefferson Davis33 min
Aug 26, 10:26 PM CDTTornado WarningLCHIberia, Vermilion34 min
Aug 26, 10:39 PM CDTTornado WarningLCHCameron51 min
Aug 26, 10:45 PM CDTTornado WarningLCHCalcasieu, Cameron, Jefferson Davis30 min
Aug 26, 11:05 PM CDTTornado WarningLCHAcadia, Vermilion25 min
Aug 26, 11:16 PM CDTTornado WarningLCHLafayette, Vermilion29 min
Aug 26, 11:28 PM CDTTornado WarningLCHAcadia, Evangeline, Jefferson Davis, Vermilion32 min
Aug 26, 11:38 PM CDTFlash Flood WarningLCHAcadia, Allen, Evangeline, Iberia, Jefferson Davis, Lafayette and 4 more10 hr
Aug 26, 11:41 PM CDTTornado WarningLCHIberia, Lafayette, St. Mary, Vermilion34 min
Aug 27, 12:02 AM CDTTornado WarningLCHAcadia, Allen, Beauregard, Evangeline, Jefferson Davis, Lafayette and 2 more43 min
Aug 27, 12:11 AM CDTTornado WarningLCHIberia, Lafayette, Saint Martin, St. Mary, Vermilion34 min
Aug 27, 12:16 AM CDTFlash Flood WarningLCHCalcasieu, Cameron, Jefferson Davis, Vermilion9 hr
Aug 27, 12:44 AM CDTTornado WarningLCHAcadia, Allen, Beauregard, Evangeline, Iberia, Jefferson Davis and 5 more46 min
Aug 27, 1:42 AM CDTTornado WarningLCHIberia, Lafayette, Saint Martin33 min
Aug 27, 2:14 AM CDTFlash Flood WarningLCHAllen, Beauregard, Calcasieu, Jefferson Davis, Rapides, Vernon8 hr
Aug 27, 2:25 AM CDTTornado WarningLCHIberia, Saint Martin, St. Mary35 min
Aug 27, 4:00 AM CDTFlash Flood WarningLCHAcadia, Allen, Avoyelles, Evangeline, Iberia, Lafayette and 3 more6 hr
Aug 27, 4:14 AM CDTFlash Flood WarningSHVGrant, LaSalle, Natchitoches, Sabine, Winn8 hr
Aug 27, 4:18 AM CDTTornado WarningLCHIberia, Saint Martin, St. Mary27 min
Aug 27, 4:28 AM CDTFlash Flood WarningLCHHardin, Jasper, Newton, Orange, Tyler5 hr
Aug 27, 6:29 AM CDTSevere Thunderstorm WarningJANAdams, Franklin, Jefferson61 min
Aug 27, 7:01 AM CDTSevere Thunderstorm WarningLIXEast Feliciana, West Feliciana40 min
Aug 27, 7:43 AM CDTFlash Flood WarningSHVBienville, Bossier, Caddo, De Soto, Natchitoches, Red River and 1 more5 hr

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 00:00Z, 2.1 hours before the alert went out and 236 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, Slidell Radar S, LA at 00:00Z on 2020-08-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1989 joules per kilogram.LCLEL10008507005003002001001 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, Slidell Radar S, LA at 00:00Z on 2020-08-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 179 square meters per square second.193958Sfc1 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
1989 J/kg
Mixed-layer CIN
-1 J/kg
Mixed-layer LCL
724 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
179 m²/s²
0-3 km storm-relative helicity
200 m²/s²
Significant tornado parameter
0.0
Supercell composite
6.3

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 26, 7:47 PM CDTMesoscale DiscussionSPCAcadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 26 more118 min
Aug 26, 11:00 PM CDTMesoscale DiscussionSPCAcadia, Beauregard, Calcasieu, Cameron, Iberia, Jefferson Davis and 2 more2 hr
Aug 27, 1:41 AM CDTMesoscale DiscussionSPCAcadia, Allen, Evangeline, Iberia, Jefferson Davis, Lafayette and 4 more3 hr
Aug 27, 6:36 AM CDTMesoscale DiscussionSPCCaldwell, Catahoula, Concordia, East Baton Rouge, East Carroll, East Feliciana and 16 more114 min
Aug 27, 7:47 AM CDTTornado WatchSPCAscension, Assumption, Avoyelles, Bienville, Caldwell, Catahoula and 44 more8 hr
Aug 27, 11:10 AM CDTMesoscale DiscussionSPCSaint Tammany, Washington2 hr
Aug 27, 2:41 PM CDTMesoscale DiscussionSPCJefferson, Plaquemines, Saint Bernard94 min
Aug 27, 3:47 PM CDTTornado WatchSPCBolivar, Calhoun, Carroll, Coahoma, DeSoto, Grenada and 16 more8 hr
Aug 27, 5:50 PM CDTMesoscale DiscussionSPCCoahoma, DeSoto, Panola, Quitman, Tate, Tunica115 min

Nearby

Tornado Watches in Louisiana, 2020Tornado Watches in Texas, 2020Tornado Watches in Mississippi, 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.