Alert archive / Alabama / Special Weather Statements in 2012

Special Weather Statement, NWS Birmingham, AL

March 31, 2012Shelby County, Alabama

NWS Birmingham, AL issued this special weather statement at Mar 31, 2012, 8:21 PM CDT for Shelby County, Alabama. It was in force for 24 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: Mar 31, 2012, 8:21 PM CDT (01:21 UTC)
Expired: Mar 31, 2012, 8:45 PM CDT
In force: 24 min
Issued by: NWS Birmingham, AL

County Shelby County, AL

The radar

The Birmingham radar (KBMX), 7 km from the middle of the area, began a volume at 01:23 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

Time	Report	Where	Remark
Mar 31, 8:31 PM CDT	HAIL 0.25	Maylene, AL	PEA SIZED HAIL REPORTED ON HWY 17 NEAR FOX VALLEY.
Mar 31, 8:55 PM CDT	HAIL 1	Montevallo, AL

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

The nearest sounding before it

Birmingham, AL (KBMX), launched 00:00Z, 1.4 hours before the alert went out and 6 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 927 J/kg
Mixed-layer CIN: -7 J/kg
Mixed-layer LCL: 1532 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 21 m²/s²
0-3 km storm-relative helicity: 71 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

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

294 
WWUS84 KBMX 010121
SPSBMX

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
821 PM CDT SAT MAR 31 2012

ALZ025-010145-
SHELBY AL-
821 PM CDT SAT MAR 31 2012

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN SHELBY COUNTY UNTIL
845 PM CDT...

AT 818 PM CDT...THE NATIONAL WEATHER SERVICE WAS TRACKING A STRONG
THUNDERSTORM NEAR HELENA...MOVING SOUTH AT 25 MPH.

HAIL UP TO THE SIZE OF PENNIES AND WIND GUSTS UP TO 40 MPH ARE
EXPECTED WITH THIS STORM.

LOCATIONS IN OR NEAR THE PATH OF THIS STORM INCLUDE...
  ALABASTER...
  MONTEVALLO...
  CALERA...
  MAYLENE...
  SHELBY COUNTY AIRPORT...


&&

LAT...LON 3307 8664 3307 8665 3307 8688 3305 8689
      3306 8691 3325 8699 3327 8697 3327 8694
      3333 8688 3333 8684 3336 8683 3336 8681
TIME...MOT...LOC 0121Z 338DEG 20KT 3326 8688

$$

GRANTHAM

The office that day

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

Issued	Product	Office	Counties	Lasted
Mar 31, 7:13 PM CDT	Severe Thunderstorm Warning	BMX	Jefferson	47 min
Mar 31, 7:15 PM CDT	Special Weather Statement	BMX	Clay, Randolph, Talladega	45 min
Mar 31, 7:23 PM CDT	Severe Thunderstorm Warning	BMX	Walker	52 min
Mar 31, 7:39 PM CDT	Severe Thunderstorm Warning	BMX	Winston	51 min
Mar 31, 7:55 PM CDT	Special Weather Statement	BMX	Chambers, Coosa, Elmore, Lee, Tallapoosa	50 min
Mar 31, 7:58 PM CDT	Severe Thunderstorm Warning	BMX	Bibb, Jefferson, Tuscaloosa	47 min
Mar 31, 8:14 PM CDT	Severe Thunderstorm Warning	BMX	Jefferson, Tuscaloosa, Walker	46 min
Mar 31, 8:28 PM CDT	Severe Thunderstorm Warning	BMX	Fayette, Walker, Winston	47 min
Mar 31, 8:36 PM CDT	Severe Thunderstorm Warning	BMX	Bibb, Chilton, Shelby	39 min
Mar 31, 8:44 PM CDT	Areal Flood Advisory	BMX	Jefferson, Shelby	106 min
Mar 31, 8:59 PM CDT	Severe Thunderstorm Warning	BMX	Bibb, Jefferson, Tuscaloosa	46 min
Mar 31, 9:10 PM CDT	Special Weather Statement	BMX	Chilton	50 min
Mar 31, 9:12 PM CDT	Special Weather Statement	BMX	Walker	48 min
Mar 31, 9:39 PM CDT	Special Weather Statement	BMX	Bibb	51 min
Mar 31, 9:56 PM CDT	Special Weather Statement	BMX	Autauga	49 min
Mar 31, 9:57 PM CDT	Special Weather Statement	BMX	Marion	48 min
Mar 31, 10:03 PM CDT	Severe Thunderstorm Warning	BMX	Marion	42 min
Mar 31, 10:39 PM CDT	Severe Thunderstorm Warning	BMX	Lamar, Marion	51 min
Mar 31, 11:29 PM CDT	Special Weather Statement	BMX	Lamar	46 min

Nearby

Special Weather Statements in Alabama, 2012 Every special weather statement in 2012

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.