Alert archive / Georgia / Tornado Watches in 2011

Tornado Watch 95

April 4, 201134 counties in Alabama; 38 counties in Georgia

The Storm Prediction Center issued this tornado watch at Apr 4, 2011, 4:55 PM CDT for 34 counties in Alabama; 38 counties in Georgia. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Apr 4, 2011, 4:55 PM CDT (21:55 UTC)
Expired
Apr 4, 2011, 11:00 PM CDT
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
1.5 in
Strongest gust expected
60 kt
All 72 counties

Autauga County, AL, Bibb County, AL, Blount County, AL, Calhoun County, AL, Chambers County, AL, Cherokee County, AL, Chilton County, AL, Clay County, AL, Cleburne County, AL, Coosa County, AL, Dallas County, AL, Elmore County, AL, Etowah County, AL, Fayette County, AL, Greene County, AL, Hale County, AL, Jefferson County, AL, Lamar County, AL, Lee County, AL, Lowndes County, AL, Macon County, AL, Marengo County, AL, Montgomery County, AL, Perry County, AL, Pickens County, AL, Randolph County, AL, Shelby County, AL, St. Clair County, AL, Sumter County, AL, Talladega County, AL, Tallapoosa County, AL, Tuscaloosa County, AL, Walker County, AL, Winston County, AL, Banks County, GA, Barrow County, GA, Bartow County, GA, Carroll County, GA, Catoosa County, GA, Chattooga County, GA, Cherokee County, GA, Clayton County, GA, Cobb County, GA, Coweta County, GA, Dade County, GA, Dawson County, GA, DeKalb County, GA, Douglas County, GA, Fannin County, GA, Fayette County, GA, Floyd County, GA, Forsyth County, GA, Fulton County, GA, Gilmer County, GA, Gordon County, GA, Gwinnett County, GA, Hall County, GA, Haralson County, GA, Heard County, GA, Jackson County, GA, Lumpkin County, GA, Meriwether County, GA, Murray County, GA, Paulding County, GA, Pickens County, GA, Polk County, GA, Towns County, GA, Troup County, GA, Union County, GA, Walker County, GA, White County, GA, Whitfield County, GA

The radar

The Birmingham radar (KBMX), 119 km from the middle of the area, began a volume at 21:58 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
50%
Ten or more severe wind reports
70%
One or more gusts of 65 knots or more
30%
Ten or more severe hail reports
20%
One or more hailstones of 2 inches or more
10%
Six or more combined severe hail and wind reports
90%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Apr 4, 5:20 PM CDTSevere Thunderstorm WarningFFCCatoosa, Dade, Walker40 min
Apr 4, 5:25 PM CDTSevere Thunderstorm WarningBMXFayette, Lamar, Pickens50 min
Apr 4, 5:30 PM CDTSevere Thunderstorm WarningBMXWalker, Winston45 min
Apr 4, 5:52 PM CDTSevere Thunderstorm WarningBMXFayette, Walker53 min
Apr 4, 6:07 PM CDTSevere Thunderstorm WarningBMXFayette, Pickens, Tuscaloosa, Walker38 min
Apr 4, 6:16 PM CDTSevere Thunderstorm WarningBMXBlount, Walker, Winston44 min
Apr 4, 6:18 PM CDTSevere Thunderstorm WarningBMXGreene, Pickens, Sumter, Tuscaloosa57 min
Apr 4, 6:20 PM CDTSevere Thunderstorm WarningBMXWalker, Winston40 min
Apr 4, 6:34 PM CDTSevere Thunderstorm WarningBMXBlount, Jefferson, Walker41 min
Apr 4, 6:40 PM CDTSevere Thunderstorm WarningBMXGreene, Pickens, Sumter, Tuscaloosa50 min
Apr 4, 7:06 PM CDTSevere Thunderstorm WarningBMXGreene, Hale, Marengo, Sumter54 min
Apr 4, 7:08 PM CDTSevere Thunderstorm WarningBMXBibb, Hale, Jefferson, Shelby, Tuscaloosa67 min
Apr 4, 7:11 PM CDTSevere Thunderstorm WarningBMXBlount, Etowah, Jefferson, St. Clair, Shelby64 min
Apr 4, 7:25 PM CDTFlash Flood WarningBMXLamar3 hr
Apr 4, 7:26 PM CDTSevere Thunderstorm WarningFFCDade, Walker49 min
Apr 4, 7:27 PM CDTSevere Thunderstorm WarningBMXCherokee48 min
Apr 4, 7:40 PM CDTFlash Flood WarningBMXBlount, Jefferson, St. Clair, Walker3 hr
Apr 4, 7:43 PM CDTSevere Thunderstorm WarningFFCChattooga, Floyd, Walker62 min
Apr 4, 7:49 PM CDTSevere Thunderstorm WarningBMXCalhoun, Cleburne, Talladega41 min
Apr 4, 7:49 PM CDTSevere Thunderstorm WarningBMXBibb, Hale, Perry26 min
Apr 4, 7:56 PM CDTSevere Thunderstorm WarningBMXHale, Marengo, Perry34 min
Apr 4, 8:07 PM CDTSevere Thunderstorm WarningBMXBibb, Chilton, Coosa, Perry, Shelby, Talladega38 min
Apr 4, 8:09 PM CDTSevere Thunderstorm WarningFFCGilmer, Gordon, Murray, Pickens, Whitfield51 min
Apr 4, 8:13 PM CDTSevere Thunderstorm WarningBMXBibb, Perry17 min
Apr 4, 8:15 PM CDTSevere Thunderstorm WarningFFCFloyd, Polk45 min
Apr 4, 8:16 PM CDTSevere Thunderstorm WarningBMXJefferson, Shelby29 min
Apr 4, 8:17 PM CDTSevere Thunderstorm WarningFFCFannin, Gilmer, Murray, Whitfield43 min
Apr 4, 8:25 PM CDTSevere Thunderstorm WarningBMXAutauga, Chilton, Dallas, Lowndes, Marengo, Perry65 min
Apr 4, 8:27 PM CDTSevere Thunderstorm WarningFFCBartow48 min
Apr 4, 8:29 PM CDTSevere Thunderstorm WarningBMXCalhoun, Cherokee, Cleburne, St. Clair, Shelby, Talladega46 min
Apr 4, 8:37 PM CDTSevere Thunderstorm WarningBMXAutauga, Chilton, Clay, Coosa, Shelby, Talladega38 min
Apr 4, 8:45 PM CDTSevere Thunderstorm WarningFFCFannin, Towns, Union45 min
Apr 4, 8:54 PM CDTSevere Thunderstorm WarningFFCBartow, Cherokee, Cobb, Paulding, Polk51 min
Apr 4, 8:56 PM CDTSevere Thunderstorm WarningFFCDawson, Lumpkin, Pickens, White49 min
Apr 4, 8:58 PM CDTSevere Thunderstorm WarningBMXCalhoun, Cleburne, Randolph, Talladega47 min
Apr 4, 9:03 PM CDTSevere Thunderstorm WarningFFCHaralson42 min
Apr 4, 9:10 PM CDTSevere Thunderstorm WarningBMXClay, Coosa, Randolph, Tallapoosa35 min
Apr 4, 9:14 PM CDTSevere Thunderstorm WarningBMXAutauga, Elmore, Lowndes, Montgomery31 min
Apr 4, 9:29 PM CDTSevere Thunderstorm WarningFFCCarroll, Cobb, Douglas, Haralson, Paulding46 min
Apr 4, 9:40 PM CDTSevere Thunderstorm WarningBMXBullock, Elmore, Lee, Lowndes, Macon, Montgomery and 1 more65 min
Apr 4, 9:42 PM CDTSevere Thunderstorm WarningBMXChambers, Clay, Cleburne, Elmore, Randolph, Tallapoosa63 min
Apr 4, 9:44 PM CDTSevere Thunderstorm WarningFFCDawson, Hall, Lumpkin, White46 min
Apr 4, 9:52 PM CDTSevere Thunderstorm WarningFFCCherokee, Cobb, Forsyth, Fulton53 min
Apr 4, 9:59 PM CDTSevere Thunderstorm WarningFFCCoweta, Heard, Troup31 min
Apr 4, 10:10 PM CDTSevere Thunderstorm WarningFFCClayton, Cobb, Fulton65 min
Apr 4, 10:15 PM CDTSevere Thunderstorm WarningFFCCarroll, Cobb, Douglas, Heard45 min
Apr 4, 10:27 PM CDTSevere Thunderstorm WarningFFCBanks, Barrow, Gwinnett, Hall, Jackson48 min
Apr 4, 10:31 PM CDTSevere Thunderstorm WarningFFCDeKalb, Gwinnett44 min
Apr 4, 10:33 PM CDTSevere Thunderstorm WarningFFCClayton, Coweta, Fayette, Harris, Meriwether, Troup57 min
Apr 4, 10:39 PM CDTSevere Thunderstorm WarningBMXBarbour, Bullock, Chambers, Lee, Macon, Russell51 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, 9.9 hours before the alert went out and 119 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 2011-04-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 45 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, Birmingham, AL at 12:00Z on 2011-04-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 150 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
45 J/kg
Mixed-layer CIN
-348 J/kg
Mixed-layer LCL
509 m above ground
0-6 km bulk shear
24 kt
0-1 km storm-relative helicity
150 m²/s²
0-3 km storm-relative helicity
332 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

416 
WWUS20 KWNS 042155
SEL5  
SPC WW 042155
ALZ000-GAZ000-050400-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 95
NWS STORM PREDICTION CENTER NORMAN OK
455 PM CDT MON APR 4 2011

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF 

       CENTRAL ALABAMA
       NORTHERN GEORGIA

EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 455 PM UNTIL
1100 PM CDT.

TORNADOES...HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 80 STATUTE
MILES EAST AND WEST OF A LINE FROM 65 MILES NORTHEAST OF ROME
GEORGIA TO 25 MILES SOUTH SOUTHWEST OF SELMA ALABAMA.  FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU5).

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 91...WW 93...WW 94...

DISCUSSION...AN INTENSE LINE OF THUNDERSTORMS IS TRACKING ACROSS
PORTIONS OF MS/AL WHERE MODERATE INSTABILITY AND STRONG SHEAR IS
PRESENT.  DAMAGING WINDS AND HAIL ARE THE MAIN THREAT. 
HOWEVER...STRONG SURFACE PRESSURE FALLS IN THE WARM SECTOR COUPLED
WITH FAVORABLE LOW LEVEL VERTICAL SHEAR WILL PROMOTE SUPERCELLS
CAPABLE OF TORNADOES.  STRONG TORNADOES CANNOT BE RULED
OUT...ESPECIALLY OVER THE AL PORTION OF THE WATCH THIS EVENING.

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
500. MEAN STORM MOTION VECTOR 26040.


...HART

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 4, 10:25 AM CDTMesoscale DiscussionSPCColbert, Cullman, Fayette, Franklin, Lamar, Lauderdale and 9 more2 hr
Apr 4, 1:03 PM CDTTornado WatchSPCBlount, Colbert, Cullman, DeKalb, Fayette, Franklin and 16 more7 hr
Apr 4, 2:52 PM CDTMesoscale DiscussionSPCChoctaw, Fayette, Greene, Pickens, Sumter, Tuscaloosa113 min
Apr 4, 4:28 PM CDTMesoscale DiscussionSPCAutauga, Baldwin, Bullock, Butler, Calhoun, Chambers and 29 more62 min
Apr 4, 5:28 PM CDTTornado WatchSPCBaldwin, Butler, Choctaw, Clarke, Conecuh, Covington and 6 more7 hr
Apr 4, 6:50 PM CDTMesoscale DiscussionSPCAutauga, Baldwin, Bibb, Blount, Butler, Calhoun and 36 more85 min
Apr 4, 3:49 PM CDTMesoscale DiscussionSPCCatoosa, Dade, Fannin, Gilmer, Gordon, Murray and 4 more56 min

Nearby

Tornado Watches in Georgia, 2011Tornado Watches in Alabama, 2011Every tornado watch in 2011

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.