Alert archive / Louisiana / Severe Thunderstorm Watches in 2021
Severe Thunderstorm Watch 88
The Storm Prediction Center issued this severe thunderstorm watch at Apr 10, 2021, 12:52 AM CDT for Columbia County, Union County, Arkansas; 17 parishes in Louisiana; 12 counties in Texas. It was in force for 3 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 10, 2021, 12:52 AM CDT (05:52 UTC)
- Expired
- Apr 10, 2021, 4:02 AM CDT
- In force
- 3 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1 in
- Strongest gust expected
- 55 kt
All 31 counties
Columbia 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, Natchitoches Parish, LA, Ouachita Parish, LA, Red River Parish, LA, Sabine Parish, LA, Union Parish, LA, Webster 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
The radar
The Shreveport radar (KSHV), 52 km from the middle of the area, began a volume at 05:57 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
- 10%
- One or more EF2 to EF5 tornadoes
- 5%
- Ten or more severe wind reports
- 40%
- One or more gusts of 65 knots or more
- 10%
- Ten or more severe hail reports
- 10%
- One or more hailstones of 2 inches or more
- 10%
- Six or more combined severe hail and wind reports
- 60%
Warnings issued inside it
1 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 10, 3:04 AM CDT | Severe Thunderstorm Warning | SHV | Angelina, Nacogdoches, Sabine, San Augustine | 56 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, 5.9 hours before the alert went out and 43 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.
- Mixed-layer CAPE
- 148 J/kg
- Mixed-layer CIN
- -321 J/kg
- Mixed-layer LCL
- 2441 m above ground
- 0-6 km bulk shear
- 52 kt
- 0-1 km storm-relative helicity
- 329 m²/s²
- 0-3 km storm-relative helicity
- 421 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
653 WWUS20 KWNS 100547 SEL8 SPC WW 100547 ARZ000-LAZ000-TXZ000-101000- URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 88 NWS Storm Prediction Center Norman OK 1250 AM CDT Sat Apr 10 2021 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Far southern Arkansas Northern Louisiana Northeast Texas * Effective this Saturday morning from 1250 AM until 500 AM CDT. * Primary threats include... Scattered damaging wind gusts to 65 mph possible SUMMARY...Clusters along the cold front should persist and will pose a conditional threat for damaging winds as it spreads southeast. The severe thunderstorm watch area is approximately along and 80 statute miles east and west of a line from 25 miles west northwest of El Dorado AR to 65 miles west southwest of Natchitoches LA. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU8). 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 84...WW 85...WW 86...WW 87... AVIATION...A few severe thunderstorms with hail surface and aloft to 1 inch. Extreme turbulence and surface wind gusts to 55 knots. A few cumulonimbi with maximum tops to 450. Mean storm motion vector 29045. ...Grams
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 9, 8:44 PM CDT | Severe Thunderstorm Watch | SPC | Benton, Boone, Carroll, Clark, Crawford, Franklin and 23 more | 5 hr |
| Apr 9, 10:25 PM CDT | Severe Thunderstorm Watch | SPC | Avoyelles, Catahoula, Concordia, East Baton Rouge, East Feliciana, Evangeline and 10 more | 6 hr |
| Apr 9, 10:47 PM CDT | Mesoscale Discussion | SPC | De Soto, Natchitoches, Red River, Sabine, Vernon | 118 min |
| Apr 9, 11:00 PM CDT | Mesoscale Discussion | SPC | Acadia, Allen, Ascension, Avoyelles, Concordia, East Baton Rouge and 16 more | 2 hr |
| Apr 10, 12:16 AM CDT | Tornado Watch | SPC | Acadia, Allen, Ascension, Assumption, Avoyelles, East Baton Rouge and 19 more | 7 hr |
| Apr 9, 8:21 PM CDT | Mesoscale Discussion | SPC | Bosque, Collin, Coryell, Dallas, Delta, Ellis and 17 more | 3 hr |
Nearby
Severe Thunderstorm Watches in Louisiana, 2021Severe Thunderstorm Watches in Texas, 2021Severe Thunderstorm Watches in Arkansas, 2021Every severe thunderstorm watch in 2021
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.