Alert archive / Alabama / Tornado Warnings in 2011

Tornado Warning 42, NWS Birmingham, AL

April 11, 2011Jefferson County, Shelby County, Alabama

NWS Birmingham, AL issued this tornado warning at Apr 11, 2011, 7:19 PM CDT for Jefferson County, Shelby County, Alabama. It was in force for 21 min. 10 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Apr 11, 2011, 7:19 PM CDT (00:19 UTC)
Expired
Apr 11, 2011, 7:40 PM CDT
In force
21 min
Issued by
NWS Birmingham, AL
Area
Storm-based polygon

Counties Jefferson County, AL, Shelby County, AL

The radar

The Birmingham radar (KBMX), 28 km from the middle of the area, began a volume at 00:21 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 was reported inside it

TimeReportWhereRemark
Apr 11, 7:27 PM CDTTSTM WND DMGHoover, ALNUMEROUS TREES ON HOUSES, POWERLINES DOWN, AND TREES DOWN ACROSS BLUFF PARK AREA. MAJOR STRUCTURAL DAMAGE TO ONE HOUSE.
Apr 11, 7:27 PM CDTTORNADO 15 S Birmingham, ALPATH WAS .4 MILES IN LENGTH AND 100 YARD IN WIDTH. PEAK WINDS WERE ESTIMATED AT 100 MPH. AFFECTED THE VESTAVIA HILLS AREA. DAMAGE PATH WAS FROM THE VESTAVIA HILLS POLICE DEPARTMENT...ACROSS BIRD PARK...TO JUST NORTH OF THE VESTAVIA HILLS COUNTRY CLUB. NUMEROUS
Apr 11, 7:28 PM CDTTSTM WND DMG2 Se Homewood, ALTREE DOWN AT THE CORNER OF HAVILAND DR AND GEORGIA AVE.
Apr 11, 7:28 PM CDTTSTM WND DMG3 Ssw Homewood, ALTREES DOWN AND POWERLINE ACROSS HACKBERRY LANE.
Apr 11, 7:28 PM CDTTSTM WND DMGVestavia Hills, ALTREES AND POWERLINES DOWN ON SUNNYWOOD CIRCLE AT VESTRIDGE RD. TREE ON VEHICLE.
Apr 11, 7:30 PM CDTTSTM WND DMG5 Ssw Birmingham, ALTREE DOWN ON WEST VALLEY AVE IN HOMEWOOD.
Apr 11, 7:30 PM CDTTSTM WND DMGVestavia Hills, ALTREES AND POWERLINES DOWN NEAR HAYES CIRCLE.
Apr 11, 7:34 PM CDTTSTM WND DMGCahaba Heights, ALTREE DOWN ON HOUSE ON MEADOW LAWN NEAR DOLLY RIDGE.
Apr 11, 7:34 PM CDTTSTM WND DMGPelham, ALLARGE TREE BLOCKING CHANDAFERN DR.
Apr 11, 7:40 PM CDTTSTM WND DMG6 Se Mountain Brook, ALTREE DOWN ON A VEHICLE ON BROOK HIGHLAND LANE. NO INJURIES REPORTED.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Apr 11, 4:05 PM CDTTornado WatchSPC6 hr

The nearest sounding before it

Birmingham, AL (KBMX), launched 00:00Z, 0.3 hours before the alert went out and 27 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 00:00Z on 2011-04-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 557 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 00:00Z on 2011-04-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 271 square meters per square second.1939587897Sfc1 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
557 J/kg
Mixed-layer CIN
-23 J/kg
Mixed-layer LCL
1487 m above ground
0-6 km bulk shear
69 kt
0-1 km storm-relative helicity
271 m²/s²
0-3 km storm-relative helicity
323 m²/s²
Significant tornado parameter
0.6
Supercell composite
9.2

Open this sounding in Storm Lab

The text

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

123 
WFUS54 KBMX 120019
TORBMX
ALC073-117-120100-
/O.NEW.KBMX.TO.W.0042.110412T0019Z-110412T0100Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE BIRMINGHAM AL
719 PM CDT MON APR 11 2011

THE NATIONAL WEATHER SERVICE IN BIRMINGHAM HAS ISSUED A

* TORNADO WARNING FOR...
  SOUTH CENTRAL JEFFERSON COUNTY IN CENTRAL ALABAMA...
  NORTHERN SHELBY COUNTY IN CENTRAL ALABAMA...

* UNTIL 800 PM CDT

* AT 717 PM CDT...THE NATIONAL WEATHER SERVICE INDICATED A SEVERE
  THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS STORM
  WAS LOCATED NEAR BESSEMER...AND MOVING EAST AT 40 MPH.

* LOCATIONS IMPACTED INCLUDE...
  HOOVER...HOMEWOOD...VESTAVIA HILLS...PELHAM...CHELSEA...ROSS
  BRIDGE...BLUFF PARK...REGIONS PARK OR HOOVER MET...RIVERCHASE AND
  RIVERCHASE GALLERIA.

THIS INCLUDES...
INTERSTATE 65 EXIT NUMBERS 246 THROUGH 258...
INTERSTATE 459 EXIT NUMBERS 6 THROUGH 23...
INTERSTATE 20 EXIT NUMBERS 113 THROUGH 115...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW. FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE
LOWEST FLOOR OF A STURDY BUILDING.

THIS LINE OF THUNDERSTORMS IS CAPABLE OF PRODUCING TORNADOES AND
WIDESPREAD SIGNIFICANT WIND DAMAGE. DO NOT WAIT TO SEE OR HEAR THE
TORNADO. FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST
FLOOR OF YOUR HOME OR BUSINESS.

&&

TO REPORT SEVERE WEATHER...
CALL 1-800-856-0758.

LAT...LON 3350 8645 3323 8648 3333 8698 3347 8696
TIME...MOT...LOC 0020Z 273DEG 35KT 3339 8692

$$

14
1 follow-up statement
802 
WWUS54 KBMX 120040
SVSBMX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
740 PM CDT MON APR 11 2011

ALC073-117-120050-
/O.CAN.KBMX.TO.W.0042.000000T0000Z-110412T0100Z/
SHELBY AL-JEFFERSON AL-
740 PM CDT MON APR 11 2011

...THE TORNADO WARNING FOR SOUTH CENTRAL JEFFERSON AND NORTHERN
SHELBY COUNTIES IS CANCELLED...

THE STORM WHICH PROMPTED THE WARNING HAS WEAKENED BELOW SEVERE
LIMITS...AND NO LONGER POSES AN IMMEDIATE THREAT TO LIFE OR PROPERTY.

REMEMBER...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 745.

TO REPORT SEVERE WEATHER...CALL 1-800-856-0758.

LAT...LON 3350 8645 3323 8648 3333 8698 3347 8696
TIME...MOT...LOC 0040Z 273DEG 35KT 3337 8669

$$

56

The office that day

Everything else NWS Birmingham, AL issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 11, 7:28 PM CDTSevere Thunderstorm WarningBMXBlount, Calhoun, Etowah, Jefferson, St. Clair, Talladega62 min
Apr 11, 7:30 PM CDTSevere Thunderstorm WarningBMXDallas, Hale, Marengo, Perry60 min
Apr 11, 7:34 PM CDTTornado WarningBMXMarengo26 min
Apr 11, 7:34 PM CDTTornado WarningBMXJefferson, St. Clair, Shelby19 min
Apr 11, 7:41 PM CDTSevere Thunderstorm WarningBMXAutauga, Bibb, Chilton, Clay, Coosa, Dallas and 4 more64 min
Apr 11, 8:03 PM CDTSevere Thunderstorm WarningBMXCalhoun, Cherokee, Clay, Cleburne, Etowah, Randolph and 2 more57 min
Apr 11, 8:20 PM CDTSevere Thunderstorm WarningBMXAutauga, Dallas, Lowndes40 min
Apr 11, 8:39 PM CDTSevere Thunderstorm WarningBMXAutauga, Chambers, Clay, Coosa, Elmore, Montgomery and 3 more66 min
Apr 11, 8:52 PM CDTSevere Thunderstorm WarningBMXCalhoun, Cherokee, Clay, Cleburne, Randolph38 min
Apr 11, 8:53 PM CDTSevere Thunderstorm WarningBMXAutauga, Dallas, Lowndes, Montgomery, Pike67 min
Apr 11, 8:57 PM CDTTornado WarningBMXCleburne33 min
Apr 11, 9:26 PM CDTSevere Thunderstorm WarningBMXChambers, Clay, Elmore, Lee, Macon, Montgomery and 2 more49 min
Apr 11, 10:01 PM CDTSevere Thunderstorm WarningBMXBullock, Lee, Macon, Montgomery, Russell44 min

Nearby

Tornado Warnings in Alabama, 2011Every tornado warning in 2011Tornadoes 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.