Alert archive / Alabama / Tornado Watches in 2020

Tornado Watch 110

April 12, 202028 counties in Alabama; 5 counties in Mississippi

The Storm Prediction Center issued this tornado watch at Apr 12, 2020, 4:38 PM CDT for 28 counties in Alabama; 5 counties in Mississippi. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Apr 12, 2020, 4:38 PM CDT (21:38 UTC)
Expired
Apr 12, 2020, 11:37 PM CDT
In force
7 hr
Issued by
the Storm Prediction Center
Particularly dangerous situation
Yes
Largest hail expected
3 in
Strongest gust expected
60 kt
All 33 counties

Autauga County, AL, Baldwin County, AL, Bibb County, AL, Calhoun County, AL, Chilton County, AL, Choctaw County, AL, Clarke County, AL, Clay County, AL, Cleburne County, AL, Coosa County, AL, Dallas County, AL, Elmore County, AL, Greene County, AL, Hale County, AL, Jefferson County, AL, Lowndes County, AL, Marengo County, AL, Mobile County, AL, Monroe County, AL, Montgomery County, AL, Perry County, AL, Shelby County, AL, St. Clair County, AL, Sumter County, AL, Talladega County, AL, Tuscaloosa County, AL, Washington County, AL, Wilcox County, AL, George County, MS, Greene County, MS, Perry County, MS, Stone County, MS, Wayne County, MS

The radar

The Birmingham radar (KBMX), 113 km from the middle of the area, began a volume at 21:42 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
95%
One or more EF2 to EF5 tornadoes
90%
Ten or more severe wind reports
90%
One or more gusts of 65 knots or more
10%
Ten or more severe hail reports
80%
One or more hailstones of 2 inches or more
60%
Six or more combined severe hail and wind reports
95%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Apr 12, 4:50 PM CDTSevere Thunderstorm WarningBMXJefferson55 min
Apr 12, 5:07 PM CDTTornado WarningBMXJefferson53 min
Apr 12, 5:28 PM CDTSevere Thunderstorm WarningBMXBlount, St. Clair46 min
Apr 12, 7:10 PM CDTTornado WarningBMXGreene22 min
Apr 12, 7:14 PM CDTTornado WarningBMXSumter26 min
Apr 12, 8:17 PM CDTSevere Thunderstorm WarningMOBWayne43 min
Apr 12, 8:25 PM CDTSevere Thunderstorm WarningBMXTuscaloosa38 min
Apr 12, 8:29 PM CDTFlash Flood WarningBMXFayette, Greene, Jefferson, Pickens, Sumter, Tuscaloosa and 1 more5 hr
Apr 12, 8:32 PM CDTTornado WarningBMXJefferson, Tuscaloosa21 min
Apr 12, 8:36 PM CDTSevere Thunderstorm WarningBMXBlount, Jefferson54 min
Apr 12, 8:36 PM CDTTornado Warning Tornado observedBMXJefferson, Tuscaloosa17 min
Apr 12, 8:46 PM CDTSevere Thunderstorm WarningMOBChoctaw, Clarke, Washington44 min
Apr 12, 8:51 PM CDTSevere Thunderstorm WarningBMXJefferson39 min
Apr 12, 8:58 PM CDTTornado WarningMOBChoctaw, Clarke, Washington47 min
Apr 12, 9:05 PM CDTSevere Thunderstorm WarningMOBGreene, Perry25 min
Apr 12, 9:09 PM CDTSevere Thunderstorm WarningMOBGeorge, Greene, Perry, Stone36 min
Apr 12, 9:13 PM CDTSevere Thunderstorm WarningMOBChoctaw, Clarke, Monroe, Washington, Wilcox47 min
Apr 12, 9:19 PM CDTSevere Thunderstorm WarningBMXBlount, Etowah, Jefferson, St. Clair, Shelby71 min
Apr 12, 9:30 PM CDTSevere Thunderstorm WarningMOBClarke, Washington45 min
Apr 12, 9:33 PM CDTTornado WarningBMXMarengo27 min
Apr 12, 9:38 PM CDTTornado WarningMOBWilcox52 min
Apr 12, 9:43 PM CDTTornado WarningMOBClarke, Monroe, Wilcox35 min
Apr 12, 9:43 PM CDTTornado WarningMOBWilcox32 min
Apr 12, 9:47 PM CDTSevere Thunderstorm WarningMOBMobile, Washington43 min
Apr 12, 10:02 PM CDTSevere Thunderstorm WarningBMXDallas27 min
Apr 12, 10:04 PM CDTSevere Thunderstorm WarningMOBWashington41 min
Apr 12, 10:06 PM CDTSevere Thunderstorm WarningMOBClarke, Washington39 min
Apr 12, 10:14 PM CDTSevere Thunderstorm WarningMOBButler, Clarke, Monroe, Wilcox46 min
Apr 12, 10:22 PM CDTFlash Flood WarningBMXBlount, Calhoun, Cherokee, Etowah, St. Clair4 hr
Apr 12, 10:32 PM CDTSevere Thunderstorm WarningMOBBaldwin, Clarke, Conecuh, Escambia, Mobile, Monroe and 1 more43 min
Apr 12, 10:34 PM CDTSevere Thunderstorm WarningMOBClarke, Conecuh, Monroe56 min
Apr 12, 10:37 PM CDTSevere Thunderstorm WarningBMXLowndes, Montgomery53 min
Apr 12, 10:47 PM CDTSevere Thunderstorm WarningBMXCalhoun, Cherokee, Cleburne, Etowah58 min
Apr 12, 10:53 PM CDTSevere Thunderstorm WarningBMXAutauga, Elmore43 min
Apr 12, 10:59 PM CDTSevere Thunderstorm WarningBMXChilton, Clay, Coosa, Shelby, Talladega, Tallapoosa43 min
Apr 12, 11:15 PM CDTSevere Thunderstorm WarningBMXBullock, Macon, Montgomery, Tallapoosa60 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

Birmingham, AL (KBMX), launched 12:00Z, 9.6 hours before the alert went out and 113 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, Birmingham, AL at 12:00Z on 2020-04-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Birmingham, AL at 12:00Z on 2020-04-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 336 square meters per square second.1939587897117Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1885 m above ground
0-6 km bulk shear
61 kt
0-1 km storm-relative helicity
336 m²/s²
0-3 km storm-relative helicity
578 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

889 
WWUS20 KWNS 122135
SEL0  
SPC WW 122135
ALZ000-MSZ000-130500-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 110
NWS Storm Prediction Center Norman OK
440 PM CDT Sun Apr 12 2020

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Central and Southern Alabama
  Southeast Mississippi

* Effective this Sunday afternoon from 440 PM until Midnight CDT.

...THIS IS A PARTICULARLY DANGEROUS SITUATION...

* Primary threats include...
  Numerous tornadoes expected with a few intense tornadoes likely
  Widespread large hail and isolated very large hail events to 3
    inches in diameter likely
  Widespread damaging wind gusts to 70 mph likely

SUMMARY...Intense supercells over southern Mississippi will track
northeastward across the watch area.  The most intense storms will
be capable of strong to violent tornadoes, very large hail, and
damaging winds afternoon and evening.

The tornado watch area is approximately along and 70 statute miles
north and south of a line from 55 miles south of Meridian MS to 35
miles south southeast of Anniston AL. For a complete depiction of
the watch see the associated watch outline update (WOUS64 KWNS
WOU0).

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 106...WW 107...WW
108...WW 109...

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 3 inches. Extreme turbulence and surface wind
gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean
storm motion vector 25035.

...Hart

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 12, 1:45 PM CDTMesoscale DiscussionSPCAutauga, Bibb, Blount, Calhoun, Cherokee, Chilton and 33 more90 min
Apr 12, 3:20 PM CDTTornado WatchSPCBibb, Blount, Calhoun, Cherokee, Chilton, Clay and 30 more8 hr
Apr 12, 3:38 PM CDTMesoscale DiscussionSPCFayette, Greene, Lamar, Pickens, Sumter, Tuscaloosa and 1 more97 min
Apr 12, 3:53 PM CDTMesoscale DiscussionSPCClarke, Washington97 min
Apr 12, 4:54 PM CDTMesoscale DiscussionSPCChoctaw66 min
Apr 12, 5:14 PM CDTMesoscale DiscussionSPCBlount, Calhoun, Cherokee, Cleburne, Cullman, DeKalb and 13 more91 min
Apr 12, 5:44 PM CDTMesoscale DiscussionSPCLamar, Marion91 min
Apr 12, 7:18 AM CDTMesoscale DiscussionSPCWarren87 min
Apr 12, 10:24 AM CDTMesoscale DiscussionSPCAdams, Attala, Calhoun, Carroll, Chickasaw, Choctaw and 42 more96 min
Apr 12, 10:41 AM CDTTornado Watch PDSSPCAdams, Attala, Bolivar, Calhoun, Carroll, Chickasaw and 47 more10 hr
Apr 12, 12:03 PM CDTMesoscale DiscussionSPCAttala, Carroll, Hinds, Holmes, Humphreys, Issaquena and 6 more87 min
Apr 12, 1:02 PM CDTMesoscale DiscussionSPCAmite, Hancock, Lamar, Marion, Pearl River, Pike and 1 more118 min
Apr 12, 1:24 PM CDTTornado WatchSPCAmite, Covington, Forrest, Franklin, Hancock, Harrison and 11 more9 hr
Apr 12, 1:40 PM CDTMesoscale DiscussionSPCAttala, Choctaw, Hinds, Holmes, Kemper, Lauderdale and 10 more95 min
Apr 12, 3:52 PM CDTMesoscale DiscussionSPCCovington, Jefferson Davis, Jones, Marion23 min
Apr 12, 4:26 PM CDTMesoscale DiscussionSPCCovington, Jasper, Jones34 min
Apr 12, 5:27 PM CDTMesoscale DiscussionSPCAmite, Pike, Walthall63 min

Nearby

Tornado Watches in Alabama, 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.