Alert archive / Alabama / Tornado Watches in 2017

Tornado Watch 182

April 30, 201733 counties in Alabama; 15 counties in Mississippi

The Storm Prediction Center issued this tornado watch at Apr 30, 2017, 10:36 AM CDT for 33 counties in Alabama; 15 counties in Mississippi. It was in force for 8 hr.

The area

The outline as issued.

The facts

Issued
Apr 30, 2017, 10:36 AM CDT (15:36 UTC)
Expired
Apr 30, 2017, 7:00 PM CDT
In force
8 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
60 kt
All 48 counties

Autauga County, AL, Baldwin County, AL, Bibb County, AL, Blount County, AL, Chilton County, AL, Choctaw County, AL, Clarke County, AL, Colbert County, AL, Cullman County, AL, Dallas County, AL, Fayette County, AL, Franklin County, AL, Greene County, AL, Hale County, AL, Jefferson County, AL, Lamar County, AL, Lauderdale County, AL, Lawrence County, AL, Limestone County, AL, Marengo County, AL, Marion County, AL, Mobile County, AL, Monroe County, AL, Morgan County, AL, Perry County, AL, Pickens County, AL, Shelby County, AL, Sumter County, AL, Tuscaloosa County, AL, Walker County, AL, Washington County, AL, Wilcox County, AL, Winston County, AL, Alcorn County, MS, Benton County, MS, Calhoun County, MS, Chickasaw County, MS, Itawamba County, MS, Lafayette County, MS, Lee County, MS, Marshall County, MS, Monroe County, MS, Pontotoc County, MS, Prentiss County, MS, Tippah County, MS, Tishomingo County, MS, Union County, MS, Yalobusha County, MS

The radar

The Columbus AFB radar (KGWX), 32 km from the middle of the area, began a volume at 15:38 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
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
5%
Six or more combined severe hail and wind reports
60%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Apr 30, 10:50 AM CDTSevere Thunderstorm WarningMEGDeSoto, Marshall, Tate40 min
Apr 30, 10:57 AM CDTSevere Thunderstorm WarningMEGLafayette, Pontotoc, Union48 min
Apr 30, 10:59 AM CDTSevere Thunderstorm WarningMEGLafayette, Pontotoc, Union46 min
Apr 30, 11:11 AM CDTSevere Thunderstorm WarningBMXGreene, Pickens, Sumter64 min
Apr 30, 11:28 AM CDTTornado WarningBMXPickens, Sumter47 min
Apr 30, 11:36 AM CDTSevere Thunderstorm WarningMEGAlcorn, Benton, Tippah39 min
Apr 30, 11:46 AM CDTTornado WarningBMXLamar44 min
Apr 30, 11:53 AM CDTSevere Thunderstorm WarningBMXLamar, Marion52 min
Apr 30, 12:12 PM CDTSevere Thunderstorm WarningBMXFayette, Greene, Pickens, Tuscaloosa63 min
Apr 30, 12:19 PM CDTTornado WarningBMXFayette, Lamar, Marion14 min
Apr 30, 12:37 PM CDTSevere Thunderstorm WarningBMXMarion23 min
Apr 30, 12:39 PM CDTTornado WarningBMXFayette22 min
Apr 30, 12:51 PM CDTSevere Thunderstorm WarningHUNColbert, Franklin, Lauderdale39 min
Apr 30, 12:54 PM CDTSevere Thunderstorm WarningBMXMarion, Walker, Winston66 min
Apr 30, 12:55 PM CDTSevere Thunderstorm WarningHUNColbert, Franklin, Lawrence50 min
Apr 30, 1:02 PM CDTSevere Thunderstorm WarningMOBWashington58 min
Apr 30, 1:06 PM CDTSevere Thunderstorm WarningMOBChoctaw, Clarke, Washington39 min
Apr 30, 1:12 PM CDTSevere Thunderstorm WarningBMXBibb, Jefferson, Tuscaloosa, Walker63 min
Apr 30, 1:25 PM CDTSevere Thunderstorm WarningHUNCullman35 min
Apr 30, 1:28 PM CDTSevere Thunderstorm WarningHUNColbert, Lauderdale, Lawrence32 min
Apr 30, 1:38 PM CDTSevere Thunderstorm WarningHUNLauderdale, Lawrence, Limestone, Morgan52 min
Apr 30, 1:45 PM CDTSevere Thunderstorm WarningBMXBlount, Jefferson60 min
Apr 30, 1:46 PM CDTSevere Thunderstorm WarningMOBChoctaw, Clarke, Washington59 min
Apr 30, 1:52 PM CDTSevere Thunderstorm WarningHUNCullman, Lawrence, Limestone, Morgan38 min
Apr 30, 1:56 PM CDTTornado WarningHUNLauderdale, Limestone19 min
Apr 30, 2:00 PM CDTSevere Thunderstorm WarningMOBClarke, Mobile, Washington60 min
Apr 30, 2:09 PM CDTTornado WarningHUNCullman, Morgan21 min
Apr 30, 2:21 PM CDTSevere Thunderstorm WarningHUNCullman, Limestone, Madison, Marshall, Morgan39 min
Apr 30, 2:41 PM CDTSevere Thunderstorm WarningBMXBlount, Etowah64 min
Apr 30, 5:49 PM CDTSevere Thunderstorm WarningMOBBaldwin, Escambia41 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, 3.6 hours before the alert went out and 144 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 2017-04-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 53 joules per kilogram.LCLLFCEL10008507005003002001001 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 2017-04-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 32 square meters per square second.193958Sfc1 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
53 J/kg
Mixed-layer CIN
-333 J/kg
Mixed-layer LCL
867 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
32 m²/s²
0-3 km storm-relative helicity
224 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

835 
WWUS20 KWNS 301534
SEL2  
SPC WW 301534
ALZ000-MSZ000-010000-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 182
NWS Storm Prediction Center Norman OK
1035 AM CDT Sun Apr 30 2017

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Western Alabama
  Northern Mississippi

* Effective this Sunday morning and evening from 1035 AM until
  700 PM CDT.

* Primary threats include...
  A few tornadoes possible
  Scattered damaging wind gusts to 70 mph possible

SUMMARY...An extensive line of storms will progress east from
Mississippi into Alabama through this afternoon. Damaging winds and
a few tornadoes will be possible.

The tornado watch area is approximately along and 75 statute miles
east and west of a line from 30 miles west northwest of Muscle
Shoals AL to 65 miles southwest of Selma AL. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU2).

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 181...

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 1 inch. Extreme turbulence and surface wind
gusts to 60 knots. A few cumulonimbi with maximum tops to 550. Mean
storm motion vector 25030.

...Grams

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 30, 10:06 AM CDTMesoscale DiscussionSPCAutauga, Bibb, Chilton, Colbert, Coosa, Cullman and 16 more84 min
Apr 30, 1:21 PM CDTMesoscale DiscussionSPCCherokee, Cleburne, DeKalb, Etowah, Jackson, Madison and 1 more54 min
Apr 30, 1:36 PM CDTTornado WatchSPCCalhoun, Chambers, Cherokee, Clay, Cleburne, Coosa and 10 more5 hr
Apr 30, 3:42 PM CDTMesoscale DiscussionSPCAutauga, Calhoun, Chambers, Cherokee, Clay, Cleburne and 8 more2 hr
Apr 30, 12:54 AM CDTMesoscale DiscussionSPCBolivar, Coahoma, DeSoto, Panola, Quitman, Sunflower and 3 more96 min
Apr 30, 1:10 AM CDTSevere Thunderstorm WatchSPCDeSoto, Tunica6 hr
Apr 30, 1:14 AM CDTMesoscale DiscussionSPCAdams, Claiborne, Jefferson, Wilkinson91 min
Apr 30, 1:49 AM CDTTornado WatchSPCAdams, Claiborne, Franklin, Issaquena, Jefferson, Sharkey and 3 more7 hr
Apr 30, 2:58 AM CDTMesoscale DiscussionSPCDeSoto, Marshall, Tate, Tunica92 min
Apr 30, 5:41 AM CDTMesoscale DiscussionSPCDeSoto, Tunica64 min
Apr 30, 6:12 AM CDTMesoscale DiscussionSPCAdams, Amite, Claiborne, Franklin, Issaquena, Jefferson and 4 more93 min
Apr 30, 6:59 AM CDTMesoscale DiscussionSPCAmite, Attala, Calhoun, Carroll, Chickasaw, Choctaw and 50 more2 hr
Apr 30, 7:32 AM CDTTornado WatchSPCAmite, Attala, Carroll, Choctaw, Clarke, Clay and 42 more7 hr

Nearby

Tornado Watches in Alabama, 2017Tornado Watches in Mississippi, 2017Every tornado watch in 2017

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.