Alert archive / Alabama / Tornado Warnings in 2011

Tornado Warning 44, NWS Birmingham, AL

April 11, 2011Jefferson County, St. Clair County, Shelby County, Alabama

NWS Birmingham, AL issued this tornado warning at Apr 11, 2011, 7:34 PM CDT for Jefferson County, St. Clair County, Shelby County, Alabama. It was in force for 19 min. 2 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, 7:34 PM CDT (00:34 UTC)
Expired
Apr 11, 2011, 7:53 PM CDT
In force
19 min
Issued by
NWS Birmingham, AL
Area
Storm-based polygon

Counties Jefferson County, AL, Shelby County, AL, St. Clair County, AL

The radar

The Birmingham radar (KBMX), 47 km from the middle of the area, began a volume at 00:34 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, 7:34 PM CDTTSTM WND DMGCahaba Heights, ALTREE DOWN ON HOUSE ON MEADOW LAWN NEAR DOLLY RIDGE.
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
Apr 11, 7:08 PM CDTTornado WatchSPC7 hr

The nearest sounding before it

Birmingham, AL (KBMX), launched 00:00Z, 0.6 hours before the alert went out and 47 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.

413 
WFUS54 KBMX 120034 RRA
TORBMX
ALC073-115-117-120100-
/O.NEW.KBMX.TO.W.0044.110412T0034Z-110412T0100Z/

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

THE NATIONAL WEATHER SERVICE IN BIRMINGHAM HAS ISSUED A

* TORNADO WARNING FOR...
  EAST CENTRAL JEFFERSON COUNTY IN CENTRAL ALABAMA...
  SOUTHWESTERN ST. CLAIR COUNTY IN CENTRAL ALABAMA...
  NORTHEASTERN SHELBY COUNTY IN CENTRAL ALABAMA...

* UNTIL 800 PM CDT

* AT 730 PM CDT...THE NATIONAL WEATHER SERVICE INDICATED A SEVERE
  THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS STORM
  WAS LOCATED NEAR SAMFORD UNIVERSITY...OR NEAR HOMEWOOD...AND MOVING
  EAST AT 40 MPH.

* LOCATIONS IMPACTED INCLUDE...
  MOUNTAIN BROOK...IRONDALE...LEEDS...TRUSSVILLE...MOODY...CAHABA
  HEIGHTS...BIRMINGHAM AIRPORT...LAKE PURDY...GREYSTONE AND ALTON.

THIS INCLUDES...
INTERSTATE 65 EXIT NUMBERS 252 THROUGH 262...
INTERSTATE 459 EXIT NUMBERS 17 THROUGH 33...
INTERSTATE 20 EXIT NUMBERS 125 THROUGH 147...
INTERSTATE 59 EXIT NUMBERS 130 THROUGH 137...

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 3372 8642 3343 8636 3340 8681 3353 8684
TIME...MOT...LOC 0034Z 254DEG 36KT 3347 8675

$$

56
2 follow-up statements
700 
WWUS54 KBMX 120043
SVSBMX

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

ALC073-115-117-120100-
/O.CON.KBMX.TO.W.0044.000000T0000Z-110412T0100Z/
SHELBY AL-JEFFERSON AL-ST. CLAIR AL-
743 PM CDT MON APR 11 2011

...A TORNADO WARNING REMAINS IN EFFECT FOR SOUTHWESTERN ST. CLAIR...
EAST CENTRAL JEFFERSON AND NORTHEASTERN SHELBY COUNTIES UNTIL 800 PM
CDT...

AT 738 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO.  THIS DANGEROUS
STORM WAS LOCATED NEAR CAHABA HEIGHTS...OR NEAR MOUNTAIN BROOK...
MOVING EAST AT 40 MPH.

LOCATIONS IMPACTED INCLUDE...
  LEEDS...TRUSSVILLE...MOODY...ALTON...BARBER MOTORSPORTS PARK...
  VANDIVER...BALD ROCK...BRANCHVILLE...MARGARET AND STERRETT.

THIS INCLUDES...
INTERSTATE 459 EXIT NUMBERS 23 THROUGH 33...
INTERSTATE 20 EXIT NUMBERS 132 THROUGH 152...
INTERSTATE 59 EXIT NUMBERS 132 THROUGH 137...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 3342 8672 3358 8674 3372 8642 3343 8636
TIME...MOT...LOC 0043Z 254DEG 36KT 3349 8664

$$

56
044 
WWUS54 KBMX 120053
SVSBMX

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

ALC073-115-117-120103-
/O.CAN.KBMX.TO.W.0044.000000T0000Z-110412T0100Z/
SHELBY AL-JEFFERSON AL-ST. CLAIR AL-
753 PM CDT MON APR 11 2011

...THE TORNADO WARNING FOR SOUTHWESTERN ST. CLAIR...EAST CENTRAL
JEFFERSON AND NORTHEASTERN 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 
845PM.

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

LAT...LON 3342 8672 3358 8674 3372 8642 3343 8636
TIME...MOT...LOC 0053Z 254DEG 36KT 3351 8652

$$

56

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 11, 7:19 PM CDTTornado WarningBMXJefferson, Shelby21 min
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, 7:41 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.