Alert archive / Louisiana / Tornado Watches in 2021
Tornado Watch 104
The Storm Prediction Center issued this tornado watch at Apr 23, 2021, 8:30 PM CDT for 22 parishes in Louisiana; 21 counties in Mississippi. It was in force for 8 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 23, 2021, 8:30 PM CDT (01:30 UTC)
- Expired
- Apr 24, 2021, 4:00 AM CDT
- In force
- 8 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
All 43 counties
Allen Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Evangeline Parish, LA, Grant Parish, LA, LaSalle Parish, LA, Livingston Parish, LA, Pointe Coupee Parish, LA, Rapides Parish, LA, Saint Helena Parish, LA, Saint Landry Parish, LA, Saint Tammany Parish, LA, Tangipahoa Parish, LA, Tensas Parish, LA, Vernon Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Adams County, MS, Amite County, MS, Claiborne County, MS, Copiah County, MS, Covington County, MS, Forrest County, MS, Franklin County, MS, Jasper County, MS, Jefferson County, MS, Jefferson Davis County, MS, Jones County, MS, Lamar County, MS, Lawrence County, MS, Lincoln County, MS, Marion County, MS, Pearl River County, MS, Pike County, MS, Simpson County, MS, Smith County, MS, Walthall County, MS, Wilkinson County, MS
The radar
The Ft Polk radar (KPOE), 111 km from the middle of the area, began a volume at 01:31 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
- 70%
- 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
- 20%
- Six or more combined severe hail and wind reports
- 90%
Warnings issued inside it
26 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 23, 9:00 PM CDT | Severe Thunderstorm Warning | LCH | Avoyelles, Rapides | 60 min |
| Apr 23, 9:00 PM CDT | Severe Thunderstorm Warning | LCH | Allen, Beauregard, Evangeline, Rapides, Vernon | 14 min |
| Apr 23, 9:28 PM CDT | Severe Thunderstorm Warning | LIX | Tangipahoa, Washington | 47 min |
| Apr 23, 9:34 PM CDT | Severe Thunderstorm Warning | LCH | Allen, Rapides | 26 min |
| Apr 23, 9:35 PM CDT | Severe Thunderstorm Warning | JAN | Catahoula, Concordia | 36 min |
| Apr 23, 9:43 PM CDT | Severe Thunderstorm Warning | LCH | Allen, Beauregard, Vernon | 13 min |
| Apr 23, 9:57 PM CDT | Severe Thunderstorm Warning | LCH | Allen, Evangeline | 33 min |
| Apr 23, 10:02 PM CDT | Severe Thunderstorm Warning | LIX | Walthall | 13 min |
| Apr 23, 10:19 PM CDT | Severe Thunderstorm Warning | LCH | Avoyelles, Evangeline, Rapides, Saint Landry | 41 min |
| Apr 23, 10:34 PM CDT | Severe Thunderstorm Warning | LIX | East Baton Rouge, Livingston, West Baton Rouge | 26 min |
| Apr 23, 10:47 PM CDT | Tornado Warning | LIX | East Baton Rouge, Livingston, West Baton Rouge | 28 min |
| Apr 23, 10:58 PM CDT | Severe Thunderstorm Warning | LCH | Avoyelles, Evangeline, Saint Landry | 46 min |
| Apr 23, 11:14 PM CDT | Severe Thunderstorm Warning | LIX | Livingston, Saint Helena, Tangipahoa | 31 min |
| Apr 23, 11:46 PM CDT | Severe Thunderstorm Warning | LIX | Saint Tammany, Tangipahoa, Washington | 44 min |
| Apr 24, 12:28 AM CDT | Severe Thunderstorm Warning | LIX | Washington | 47 min |
| Apr 24, 1:01 AM CDT | Severe Thunderstorm Warning | JAN | Forrest, Lamar | 44 min |
| Apr 24, 1:26 AM CDT | Severe Thunderstorm Warning | LIX | Amite, Pike, Walthall, Wilkinson | 49 min |
| Apr 24, 1:30 AM CDT | Severe Thunderstorm Warning | JAN | Franklin, Lincoln | 39 min |
| Apr 24, 1:50 AM CDT | Severe Thunderstorm Warning | LIX | Ascension, East Baton Rouge, Iberville, Livingston, Saint Helena, Tangipahoa | 25 min |
| Apr 24, 1:56 AM CDT | Severe Thunderstorm Warning | JAN | Covington, Jefferson Davis, Lawrence | 64 min |
| Apr 24, 2:05 AM CDT | Severe Thunderstorm Warning | JAN | Lawrence | 25 min |
| Apr 24, 2:47 AM CDT | Severe Thunderstorm Warning | JAN | Jasper, Jones, Smith | 47 min |
| Apr 24, 2:58 AM CDT | Severe Thunderstorm Warning | JAN | Hinds, Madison, Rankin, Scott, Smith | 51 min |
| Apr 24, 3:30 AM CDT | Severe Thunderstorm Warning | LIX | Ascension, Livingston, Saint James, Saint John the Baptist, Tangipahoa | 30 min |
| Apr 24, 3:42 AM CDT | Severe Thunderstorm Warning | LIX | Pearl River | 18 min |
| Apr 24, 3:55 AM CDT | Severe Thunderstorm Warning | JAN | Forrest | 6 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
Lake Charles Mun, LA (KLCH), launched 00:00Z, 1.5 hours before the alert went out and 182 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
- 865 J/kg
- Mixed-layer CIN
- -14 J/kg
- Mixed-layer LCL
- 546 m above ground
- 0-6 km bulk shear
- 87 kt
- 0-1 km storm-relative helicity
- 383 m²/s²
- 0-3 km storm-relative helicity
- 442 m²/s²
- Significant tornado parameter
- 2.4
- Supercell composite
- 10.3
The text
As transmitted.
848 WWUS20 KWNS 240128 SEL4 SPC WW 240128 LAZ000-MSZ000-240900- URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 104 NWS Storm Prediction Center Norman OK 830 PM CDT Fri Apr 23 2021 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of Parts of central and southeast Louisiana Southwest and south central Mississippi * Effective this Friday night and Saturday morning from 830 PM until 400 AM CDT. * Primary threats include... A few tornadoes likely Scattered damaging wind gusts to 70 mph likely Scattered large hail events to 1.5 inches in diameter possible SUMMARY...Clusters of storms, with embedded supercell and bowing structures, will likely persist well into the overnight hours while spreading eastward from Louisiana into Mississippi. The storm environment will favor damaging winds and large hail with the strongest storms, as well as a few tornadoes with the stronger embedded circulations. The tornado watch area is approximately along and 40 statute miles north and south of a line from 20 miles west southwest of Fort Polk LA to 5 miles south southeast of Pine Belt MS. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU4). 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 99...WW 101...WW 102...WW 103... AVIATION...Tornadoes and a few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 550. Mean storm motion vector 27035. ...Thompson
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 23, 10:29 PM CDT | Mesoscale Discussion | SPC | Allen, Avoyelles, Concordia, East Baton Rouge, East Feliciana, Evangeline and 10 more | 2 hr |
| Apr 24, 3:04 AM CDT | Mesoscale Discussion | SPC | Ascension, Assumption, Livingston, Orleans, Saint Charles, Saint James and 4 more | 116 min |
| Apr 24, 12:29 PM CDT | Mesoscale Discussion | SPC | Livingston, Orleans, Saint Bernard, Saint Charles, Saint Helena, Saint John the Baptist and 3 more | 2 hr |
| Apr 24, 1:00 AM CDT | Mesoscale Discussion | SPC | Forrest, George, Greene, Hancock, Harrison, Jackson and 2 more | 3 hr |
| Apr 24, 1:00 AM CDT | Mesoscale Discussion | SPC | Forrest, George, Greene, Hancock, Harrison, Jackson and 2 more | 3 hr |
| Apr 24, 1:23 AM CDT | Tornado Watch | SPC | George, Greene, Hancock, Harrison, Jackson, Perry and 2 more | 8 hr |
| Apr 24, 4:26 AM CDT | Mesoscale Discussion | SPC | George, Greene | 2 hr |
| Apr 24, 1:17 PM CDT | Severe Thunderstorm Watch | SPC | George, Greene, Perry, Stone, Wayne | 8 hr |
Nearby
Tornado Watches in Louisiana, 2021Tornado Watches in Mississippi, 2021Every tornado 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.