Alert archive / Mississippi / Tornado Watches in 2021

Tornado Watch 149

May 4, 20214 states

The Storm Prediction Center issued this tornado watch at May 4, 2021, 3:31 PM CDT for 4 states. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
May 4, 2021, 3:31 PM CDT (20:31 UTC)
Expired
May 4, 2021, 9:59 PM CDT
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
1.5 in
Strongest gust expected
70 kt
All 62 counties

Autauga County, AL, Baldwin County, AL, Bibb County, AL, Butler County, AL, Chilton County, AL, Choctaw County, AL, Clarke County, AL, Conecuh County, AL, Coosa County, AL, Dallas County, AL, Elmore County, AL, Escambia County, AL, Greene County, AL, Hale County, AL, Lowndes County, AL, Marengo County, AL, Mobile County, AL, Monroe County, AL, Montgomery County, AL, Perry County, AL, Pickens County, AL, Sumter County, AL, Tallapoosa County, AL, Tuscaloosa County, AL, Washington County, AL, Wilcox County, AL, Escambia County, FL, Santa Rosa County, FL, East Baton Rouge Parish, LA, Livingston Parish, LA, Saint Tammany Parish, LA, Tangipahoa Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, Clarke County, MS, Covington County, MS, Forrest County, MS, George County, MS, Greene County, MS, Hancock County, MS, Harrison County, MS, Jackson County, MS, Jasper County, MS, Jefferson Davis County, MS, Jones County, MS, Kemper County, MS, Lamar County, MS, Lauderdale County, MS, Lawrence County, MS, Lowndes County, MS, Marion County, MS, Neshoba County, MS, Newton County, MS, Noxubee County, MS, Pearl River County, MS, Perry County, MS, Pike County, MS, Smith County, MS, Stone County, MS, Walthall County, MS, Wayne County, MS, Winston County, MS

The radar

The Mobile radar (KMOB), 122 km from the middle of the area, began a volume at 20:32 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
70%
Ten or more severe hail reports
30%
One or more hailstones of 2 inches or more
20%
Six or more combined severe hail and wind reports
95%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
May 4, 3:32 PM CDTTornado WarningJANClarke, Jasper29 min
May 4, 3:33 PM CDTSevere Thunderstorm WarningLIXEast Baton Rouge, East Feliciana, Saint Helena, Tangipahoa, Washington, West Feliciana42 min
May 4, 3:36 PM CDTSevere Thunderstorm WarningJANLauderdale54 min
May 4, 3:38 PM CDTSevere Thunderstorm WarningJANCovington, Jefferson Davis, Jones, Lamar, Lawrence, Lincoln and 1 more82 min
May 4, 3:49 PM CDTSevere Thunderstorm WarningJANLowndes, Noxubee29 min
May 4, 3:50 PM CDTSevere Thunderstorm WarningBMXSumter55 min
May 4, 3:50 PM CDTSevere Thunderstorm WarningJANClarke55 min
May 4, 3:55 PM CDTSevere Thunderstorm WarningMOBChoctaw, Clarke, Washington65 min
May 4, 3:58 PM CDTSevere Thunderstorm WarningJANKemper32 min
May 4, 4:05 PM CDTFlash Flood WarningBMXBibb, Tuscaloosa3 hr
May 4, 4:10 PM CDTSevere Thunderstorm WarningLIXEast Baton Rouge, East Feliciana, Saint Helena, Saint Tammany, Tangipahoa, Washington65 min
May 4, 4:13 PM CDTSevere Thunderstorm WarningBMXTuscaloosa29 min
May 4, 4:20 PM CDTSevere Thunderstorm WarningBMXGreene55 min
May 4, 4:26 PM CDTSevere Thunderstorm WarningJANForrest, Jones, Lamar, Marion94 min
May 4, 4:30 PM CDTSevere Thunderstorm WarningBMXHale, Marengo63 min
May 4, 4:44 PM CDTSevere Thunderstorm WarningMOBBaldwin, Clarke, Mobile, Monroe, Washington61 min
May 4, 4:59 PM CDTSevere Thunderstorm WarningMOBChoctaw, Clarke, Washington, Wilcox61 min
May 4, 5:00 PM CDTSevere Thunderstorm WarningBMXBibb, Chilton, Dallas, Perry75 min
May 4, 5:29 PM CDTSevere Thunderstorm WarningBMXAutauga, Chilton, Lowndes76 min
May 4, 5:30 PM CDTTornado WarningBMXChilton, Perry30 min
May 4, 5:33 PM CDTSevere Thunderstorm WarningMOBButler, Clarke, Conecuh, Monroe, Wilcox57 min
May 4, 5:44 PM CDTSevere Thunderstorm WarningMOBBaldwin, Clarke, Mobile, Monroe, Washington61 min
May 4, 5:54 PM CDTSevere Thunderstorm WarningBMXCoosa50 min
May 4, 5:59 PM CDTSevere Thunderstorm WarningBMXElmore61 min
May 4, 6:07 PM CDTSevere Thunderstorm WarningBMXMontgomery68 min
May 4, 6:19 PM CDTSevere Thunderstorm WarningBMXTallapoosa56 min
May 4, 6:24 PM CDTTornado WarningBMXElmore, Montgomery13 min
May 4, 6:28 PM CDTSevere Thunderstorm WarningMOBButler, Conecuh, Covington, Crenshaw, Monroe, Wilcox77 min
May 4, 8:36 PM CDTFlash Flood WarningMOBMobile6 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

Jackson, MS (KJAN), launched 12:00Z, 8.5 hours before the alert went out and 158 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, Jackson, MS at 12:00Z on 2021-05-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2428 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Jackson, MS at 12:00Z on 2021-05-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 170 square meters per square second.19395878Sfc1 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
2428 J/kg
Mixed-layer CIN
-6 J/kg
Mixed-layer LCL
646 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
170 m²/s²
0-3 km storm-relative helicity
235 m²/s²
Significant tornado parameter
2.8
Supercell composite
13.2

Open this sounding in Storm Lab

The text

As transmitted.

824 
WWUS20 KWNS 042027
SEL9  
SPC WW 042027
ALZ000-FLZ000-LAZ000-MSZ000-CWZ000-050300-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 149
NWS Storm Prediction Center Norman OK
330 PM CDT Tue May 4 2021

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Central and southern Alabama
  Western Florida Panhandle
  Southeast Louisiana
  Southern to east-central Mississippi
  Coastal Waters

* Effective this Tuesday afternoon and evening from 330 PM until
  1000 PM CDT.

* Primary threats include...
  A few tornadoes possible
  Widespread damaging winds and isolated significant gusts to 80
    mph likely
  Isolated large hail events to 1.5 inches in diameter possible

SUMMARY...Mature squall line will progress east from Mississippi
across central and southern portions of Alabama. Widespread damaging
winds and brief tornadoes are expected.

The tornado watch area is approximately along and 115 statute miles
east and west of a line from 35 miles west of Mobile AL to 30 miles
east northeast of Tuscaloosa AL. For a complete depiction of the
watch see the associated watch outline update (WOUS64 KWNS WOU9).

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 144...WW 145...WW
146...WW 147...WW 148...

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 1.5 inches. Extreme turbulence and surface wind
gusts to 70 knots. A few cumulonimbi with maximum tops to 550. Mean
storm motion vector 28045.

...Grams

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 3, 7:13 PM CDTMesoscale DiscussionSPCAutauga, Bullock, Chambers, Coosa, Elmore, Lee and 4 more62 min
May 4, 5:13 AM CDTSevere Thunderstorm WatchSPCJackson, Lauderdale, Limestone, Madison5 hr
May 4, 7:31 AM CDTMesoscale DiscussionSPCJackson, Lauderdale, Limestone, Madison89 min
May 4, 8:33 AM CDTMesoscale DiscussionSPCChoctaw, Clarke, Dallas, Greene, Hale, Marengo and 4 more117 min
May 4, 9:03 AM CDTMesoscale DiscussionSPCBlount, Calhoun, Cherokee, Clay, Cleburne, Cullman and 20 more117 min
May 4, 9:18 AM CDTTornado WatchSPCAutauga, Bibb, Blount, Calhoun, Cherokee, Chilton and 28 more7 hr
May 4, 2:17 PM CDTMesoscale DiscussionSPCChoctaw, Greene, Marengo, Sumter88 min
May 4, 3:03 PM CDTMesoscale DiscussionSPCBibb, Blount, Calhoun, Cherokee, Chilton, Clay and 19 more117 min
May 4, 4:46 PM CDTMesoscale DiscussionSPCAutauga, Baldwin, Bibb, Butler, Chilton, Choctaw and 20 more89 min
May 4, 5:20 PM CDTMesoscale DiscussionSPCBarbour, Bullock, Chambers, Coffee, Covington, Dale and 7 more85 min
May 4, 6:10 PM CDTMesoscale DiscussionSPCAutauga, Coosa, Elmore, Lowndes, Macon, Montgomery and 1 more65 min
May 4, 6:26 PM CDTSevere Thunderstorm WatchSPCBarbour, Bullock, Chambers, Coffee, Covington, Crenshaw and 8 more6 hr
May 3, 9:10 PM CDTSevere Thunderstorm WatchSPCBossier, Caddo, Webster7 hr
May 4, 6:44 AM CDTMesoscale DiscussionSPCBienville, Bossier, Caddo, Claiborne, De Soto, Lincoln and 3 more2 hr
May 4, 10:52 AM CDTTornado WatchSPCAllen, Avoyelles, Beauregard, Bienville, Bossier, Caddo and 31 more7 hr
May 4, 12:16 PM CDTMesoscale DiscussionSPCCaldwell, Catahoula, Concordia, East Carroll, Franklin, Grant and 9 more89 min
May 4, 11:58 AM CDTMesoscale DiscussionSPCAlcorn, Benton, Calhoun, Chickasaw, Coahoma, DeSoto and 13 more2 hr
May 4, 12:18 PM CDTSevere Thunderstorm WatchSPCAlcorn, Benton, Calhoun, Chickasaw, Coahoma, DeSoto and 16 more5 hr

Nearby

Tornado Watches in Mississippi, 2021Tornado Watches in Alabama, 2021Tornado Watches in Louisiana, 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.