Alert archive / Louisiana / Tornado Watches in 2021
Tornado Watch 146
The Storm Prediction Center issued this tornado watch at May 4, 2021, 10:52 AM CDT for 8 counties in Arkansas; 37 parishes in Louisiana; 15 counties in Mississippi. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- May 4, 2021, 10:52 AM CDT (15:52 UTC)
- Expired
- May 4, 2021, 5:32 PM CDT
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2.5 in
- Strongest gust expected
- 70 kt
All 60 counties
Ashley County, AR, Bradley County, AR, Calhoun County, AR, Chicot County, AR, Columbia County, AR, Desha County, AR, Drew County, AR, Union County, AR, Allen Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Caldwell Parish, LA, Catahoula Parish, LA, Claiborne Parish, LA, Concordia Parish, LA, De Soto Parish, LA, East Carroll Parish, LA, East Feliciana Parish, LA, Evangeline Parish, LA, Franklin Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Pointe Coupee Parish, LA, Rapides Parish, LA, Red River Parish, LA, Richland Parish, LA, Sabine Parish, LA, Saint Helena Parish, LA, Saint Landry Parish, LA, Tensas Parish, LA, Union Parish, LA, Vernon Parish, LA, Webster Parish, LA, West Carroll Parish, LA, West Feliciana Parish, LA, Winn Parish, LA, Adams County, MS, Amite County, MS, Bolivar County, MS, Claiborne County, MS, Franklin County, MS, Grenada County, MS, Humphreys County, MS, Issaquena County, MS, Jefferson County, MS, Leflore County, MS, Sharkey County, MS, Sunflower County, MS, Warren County, MS, Washington County, MS, Wilkinson County, MS
The radar
The Ft Polk radar (KPOE), 131 km from the middle of the area, began a volume at 15:52 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
- 50%
- One or more EF2 to EF5 tornadoes
- 20%
- Ten or more severe wind reports
- 80%
- One or more gusts of 65 knots or more
- 40%
- Ten or more severe hail reports
- 40%
- One or more hailstones of 2 inches or more
- 40%
- Six or more combined severe hail and wind reports
- 95%
Warnings issued inside it
31 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 4, 11:07 AM CDT | Severe Thunderstorm Warning | SHV | De Soto | 38 min |
| May 4, 11:10 AM CDT | Severe Thunderstorm Warning | SHV | Bienville, Bossier, Caddo, De Soto, Webster | 50 min |
| May 4, 11:14 AM CDT | Severe Thunderstorm Warning | SHV | Bossier, Caddo, De Soto | 31 min |
| May 4, 11:24 AM CDT | Severe Thunderstorm Warning | SHV | Bienville, Claiborne, Jackson, Lincoln | 51 min |
| May 4, 11:43 AM CDT | Severe Thunderstorm Warning | LZK | Desha, Drew | 62 min |
| May 4, 11:52 AM CDT | Tornado Warning | LCH | Beauregard, Vernon | 23 min |
| May 4, 11:57 AM CDT | Severe Thunderstorm Warning | JAN | Ashley | 78 min |
| May 4, 12:05 PM CDT | Severe Thunderstorm Warning | SHV | Bienville, De Soto, Natchitoches, Red River, Sabine | 40 min |
| May 4, 12:17 PM CDT | Severe Thunderstorm Warning | SHV | Natchitoches, Sabine | 43 min |
| May 4, 12:18 PM CDT | Severe Thunderstorm Warning | JAN | Chicot | 72 min |
| May 4, 12:25 PM CDT | Severe Thunderstorm Warning | SHV | Bienville, Jackson, Lincoln, Ouachita, Union | 65 min |
| May 4, 12:28 PM CDT | Severe Thunderstorm Warning | SHV | Union | 47 min |
| May 4, 12:30 PM CDT | Severe Thunderstorm Warning | JAN | Chicot | 75 min |
| May 4, 12:37 PM CDT | Flash Flood Warning | JAN | Ashley, Chicot | 3 hr |
| May 4, 12:41 PM CDT | Severe Thunderstorm Warning | SHV | Bienville, Jackson, Natchitoches, Winn | 64 min |
| May 4, 12:44 PM CDT | Flash Flood Warning | LZK | Desha, Drew | 3 hr |
| May 4, 12:48 PM CDT | Severe Thunderstorm Warning | SHV | Grant, LaSalle, Winn | 57 min |
| May 4, 12:53 PM CDT | Severe Thunderstorm Warning | SHV | Caldwell, Jackson, LaSalle | 52 min |
| May 4, 12:57 PM CDT | Severe Thunderstorm Warning | JAN | East Carroll, Franklin, Madison, Richland, West Carroll | 76 min |
| May 4, 1:15 PM CDT | Severe Thunderstorm Warning | JAN | Catahoula, Concordia, Franklin, Tensas | 75 min |
| May 4, 1:19 PM CDT | Severe Thunderstorm Warning | JAN | Leflore, Sunflower | 59 min |
| May 4, 1:22 PM CDT | Severe Thunderstorm Warning | JAN | Holmes, Humphreys, Issaquena, Sharkey, Washington, Yazoo | 71 min |
| May 4, 1:37 PM CDT | Severe Thunderstorm Warning | JAN | East Carroll, Madison | 53 min |
| May 4, 1:44 PM CDT | Severe Thunderstorm Warning | JAN | Carroll, Grenada, Montgomery | 75 min |
| May 4, 1:57 PM CDT | Severe Thunderstorm Warning | JAN | Tensas | 78 min |
| May 4, 2:16 PM CDT | Severe Thunderstorm Warning | LCH | Avoyelles, Evangeline, Rapides, Saint Landry | 44 min |
| May 4, 2:26 PM CDT | Severe Thunderstorm Warning | LIX | Pointe Coupee, West Feliciana | 64 min |
| May 4, 2:40 PM CDT | Severe Thunderstorm Warning | JAN | Copiah, Franklin, Jefferson Davis, Lawrence, Lincoln, Simpson | 80 min |
| May 4, 2:58 PM CDT | Severe Thunderstorm Warning | LIX | East Feliciana, Pointe Coupee, West Feliciana | 47 min |
| May 4, 3:33 PM CDT | Severe Thunderstorm Warning | LIX | East Baton Rouge, East Feliciana, Saint Helena, Tangipahoa, Washington, West Feliciana | 42 min |
| May 4, 4:10 PM CDT | Severe Thunderstorm Warning | LIX | East Baton Rouge, East Feliciana, Saint Helena, Saint Tammany, Tangipahoa, Washington | 65 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, 3.9 hours before the alert went out and 131 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
- 2618 J/kg
- Mixed-layer CIN
- -96 J/kg
- Mixed-layer LCL
- 873 m above ground
- 0-6 km bulk shear
- 44 kt
- 0-1 km storm-relative helicity
- 208 m²/s²
- 0-3 km storm-relative helicity
- 182 m²/s²
- Significant tornado parameter
- 1.3
- Supercell composite
- 6.0
The text
As transmitted.
137
WWUS20 KWNS 041550
SEL6
SPC WW 041550
ARZ000-LAZ000-MSZ000-042300-
URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 146
NWS Storm Prediction Center Norman OK
1055 AM CDT Tue May 4 2021
The NWS Storm Prediction Center has issued a
* Tornado Watch for portions of
Southern Arkansas
Northern and central Louisiana
Western Mississippi
* Effective this Tuesday morning and evening from 1055 AM until
600 PM CDT.
* Primary threats include...
A few tornadoes possible
Widespread damaging winds likely with isolated significant gusts
to 80 mph possible
Scattered large hail and isolated very large hail events to 2.5
inches in diameter possible
SUMMARY...Multiple clusters with embedded supercells will develop
east across the region this afternoon before consolidating into one
or more squall lines across the Mississippi Valley later this
afternoon.
The tornado watch area is approximately along and 100 statute miles
north and south of a line from 30 miles west of Natchitoches LA to
60 miles northeast of Natchez MS. For a complete depiction of the
watch see the associated watch outline update (WOUS64 KWNS WOU6).
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 142...WW 143...WW
144...WW 145...
AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 2.5 inches. Extreme turbulence and surface wind
gusts to 70 knots. A few cumulonimbi with maximum tops to 600. Mean
storm motion vector 25045.
...GramsSPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 3, 8:38 PM CDT | Mesoscale Discussion | SPC | Arkansas, Baxter, Boone, Calhoun, Carroll, Clark and 60 more | 2 hr |
| May 3, 9:10 PM CDT | Severe Thunderstorm Watch | SPC | Baxter, Benton, Boone, Calhoun, Carroll, Clark and 50 more | 7 hr |
| May 3, 10:22 PM CDT | Mesoscale Discussion | SPC | Boone, Crawford, Franklin, Johnson, Madison, Marion and 2 more | 83 min |
| May 3, 11:34 PM CDT | Mesoscale Discussion | SPC | Baxter, Boone, Carroll, Clark, Cleburne, Conway and 27 more | 86 min |
| May 4, 1:06 AM CDT | Mesoscale Discussion | SPC | Clay, Craighead, Crittenden, Cross, Greene, Jackson and 5 more | 114 min |
| May 4, 1:41 AM CDT | Severe Thunderstorm Watch | SPC | Clay, Craighead, Crittenden, Cross, Greene, Mississippi and 2 more | 6 hr |
| May 4, 2:02 AM CDT | Mesoscale Discussion | SPC | Clay, Conway, Craighead, Cross, Faulkner, Garland and 16 more | 88 min |
| May 4, 4:17 AM CDT | Mesoscale Discussion | SPC | Crittenden | 88 min |
| May 4, 6:44 AM CDT | Mesoscale Discussion | SPC | Bradley, Calhoun, Clark, Cleveland, Columbia, Dallas and 8 more | 2 hr |
| May 4, 11:58 AM CDT | Mesoscale Discussion | SPC | Crittenden, Lee, Phillips | 2 hr |
| May 4, 12:18 PM CDT | Severe Thunderstorm Watch | SPC | Phillips | 5 hr |
| May 4, 1:59 PM CDT | Mesoscale Discussion | SPC | Cleburne, Conway, Craighead, Cross, Faulkner, Greene and 17 more | 2 hr |
| May 4, 8:33 AM CDT | Mesoscale Discussion | SPC | Avoyelles, Caldwell, Catahoula, Concordia, East Carroll, East Feliciana and 14 more | 117 min |
| May 4, 12:16 PM CDT | Mesoscale Discussion | SPC | Caldwell, Catahoula, Concordia, East Carroll, Franklin, Grant and 9 more | 89 min |
| May 4, 3:31 PM CDT | Tornado Watch | SPC | East Baton Rouge, Livingston, Saint Tammany, Tangipahoa, Washington, West Baton Rouge | 6 hr |
| May 4, 4:46 PM CDT | Mesoscale Discussion | SPC | Saint Tammany, Tangipahoa, Washington | 89 min |
| May 4, 9:03 AM CDT | Mesoscale Discussion | SPC | Clay, Lowndes, Monroe, Oktibbeha | 117 min |
| May 4, 9:18 AM CDT | Tornado Watch | SPC | Attala, Carroll, Choctaw, Clarke, Clay, Copiah and 26 more | 7 hr |
| May 4, 2:17 PM CDT | Mesoscale Discussion | SPC | Attala, Choctaw, Claiborne, Clarke, Copiah, Covington and 26 more | 88 min |
| May 4, 3:03 PM CDT | Mesoscale Discussion | SPC | Chickasaw, Choctaw, Clay, Itawamba, Kemper, Lowndes and 5 more | 117 min |
Nearby
Tornado Watches in Louisiana, 2021Tornado Watches in Mississippi, 2021Tornado Watches in Arkansas, 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.