Alert archive / Alabama / Special Weather Statements in 2012

Special Weather Statement, NWS Birmingham, AL

April 17, 2012Shelby County, Alabama

NWS Birmingham, AL issued this special weather statement at Apr 17, 2012, 3:06 PM CDT for Shelby County, Alabama. It was in force for 39 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Apr 17, 2012, 3:06 PM CDT (20:06 UTC)
Expired
Apr 17, 2012, 3:45 PM CDT
In force
39 min
Issued by
NWS Birmingham, AL

County Shelby County, AL

The radar

The Birmingham radar (KBMX), 42 km from the middle of the area, began a volume at 20:05 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.

The nearest sounding before it

Birmingham, AL (KBMX), launched 12:00Z, 8.1 hours before the alert went out and 41 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 2012-04-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 309 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 2012-04-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 28 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
309 J/kg
Mixed-layer CIN
-34 J/kg
Mixed-layer LCL
663 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
28 m²/s²
0-3 km storm-relative helicity
78 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.

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What forecasters said that day

The local office's own words before this special weather statement went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Birmingham, AL wrote its last area forecast discussion before this special weather statement went out at Apr 17, 12:44 PM CDT, 2 hours 22 minutes earlier.

Area forecast discussion, Apr 17, 12:44 PM CDT, 2 hours 22 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BIRMINGHAM AL
1244 PM CDT TUE APR 17 2012

.UPDATE...
FOR AVIATION.

&&

.DISCUSSION...
MAIN RAIN SHIELD HAS SET UP OVER THE NORTHWEST AND WILL REMAIN
THERE FOR SEVERAL MORE HOURS AS THE UPPER TROUGH BEGINS TO SWING
THROUGH THE SOUTHEAST. THERE IS A SHARP CLOUD FEATURE SHOWING UP
IN CENTRAL MISSISSIPPI IS ON THE WESTERN SIDE OF THE HEAVIER RAIN
SHIELD. ALSO WATCHING A SURFACE LOW BEGIN TO SWING NORTH AHEAD OF
THIS FEATURE. EXPECT RAINFALL TO CONTINUE TO MOVE NORTH OVER THE
NEXT FEW HOURS...BUT THEN SPREAD EAST THIS AFTERNOON AS THE TROUGH
SWINGS THROUGH. TRIED TO ADJUST TEMPERATURES BASED ON THIS TREND
WITH THE WARMEST IN THE SOUTHEAST AND COOLEST IN THE RAIN COOLED
AREAS. LOOK FOR ISOLATED SHOWERS TO DEVELOP AHEAD OF THIS BOUNDARY
AS WELL IN THE EASTERN HALF OF THE AREA...ESPECIALLY WITH THE
HEATING OF THE DAY. WENT AHEAD AND RAISED POPS EVEN MORE ACROSS
THE NORTH AND WEST. UPDATES HAVE BEEN SENT.

16

&&

.AVIATION...
18Z TAF DISCUSSION

THE MAIN RAIN BAND REMAINS WEST OF THE TAF SITES...HOWEVER WE ARE
BEGINNING TO SEE ISOLATED SHOWERS AND THUNDERSTORMS DEVELOPING
AHEAD OF THE LINE. EXPECT VC TS IN AFTER 19Z FOR MOST SITES. LOOK
FOR THE MAIN SHIELD TO WORK IN FOR THE AFTERNOON AND REMAIN THROUGH
THE EVENING. ONCE THE MAIN RAIN BAND LEAVES AFTER 6 TO 8Z FOR THE
NORTH LOW CLOUDS WILL BECOME THE MAIN PLAYER WITH IFR CIGS EXPECTED
ONCE AGAIN. MAY BE SOME DRIZZLE OR LIGHT RAIN AS WELL...BUT STUCK
WITH MIST AS THE QUALIFIER FOR NOW. MAY SEE CIGS RISE TO MVFR BY THE
END OF THE CYCLE BUT FOR TAF LENGTH CONTINUED WITH IFR THROUGH THE
END.

&&

.BMX WATCHES/WARNINGS/ADVISORIES...
NONE.

&&
Hazardous weather outlook, Apr 17, 3:05 PM CDT, 1 minute before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BIRMINGHAM AL
305 PM CDT TUE APR 17 2012

ALZ011>015-017>050-182015-
MARION-LAMAR-FAYETTE-WINSTON-WALKER-BLOUNT-ETOWAH-CALHOUN-CHEROKEE-
CLEBURNE-PICKENS-TUSCALOOSA-JEFFERSON-SHELBY-ST. CLAIR-TALLADEGA-
CLAY-RANDOLPH-SUMTER-GREENE-HALE-PERRY-BIBB-CHILTON-COOSA-TALLAPOOSA-
CHAMBERS-MARENGO-DALLAS-AUTAUGA-LOWNDES-ELMORE-MONTGOMERY-MACON-
BULLOCK-LEE-RUSSELL-PIKE-BARBOUR-
305 PM CDT TUE APR 17 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE COUNTIES SERVED BY THE
NATIONAL WEATHER SERVICE OFFICE IN BIRMINGHAM.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

SHOWERS AND THUNDERSTORMS WILL CONTINUE TO DEVELOP ACROSS CENTRAL
ALABAMA THIS AFTERNOON AND EVENING HOURS. AN ISOLATED SEVERE
THUNDERSTORM WILL BE POSSIBLE THROUGH 8 PM FOR AREAS NORTH OF
INTERSTATE 85 AND EAST OF A DEMOPOLIS TO CORDOVA LINE. GUSTY WINDS
AND LARGE HAIL WILL BE THE THREATS FOR THE STRONGEST STORMS.

THE SEVERE POTENTIAL WILL DIMINISH FROM THE WEST AS THE LINE OF
MORE WIDESPREAD RAINS MOVE IN.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

ACTIVATION OF STORM SPOTTERS AND EMERGENCY MANAGEMENT MAY BE
NEEDED THROUGH EARLY THIS EVENING.

In the hours before

Special weather statement, Apr 17, 2:21 PM CDT, 45 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
221 PM CDT TUE APR 17 2012

ALZ024-025-172000-
JEFFERSON AL-SHELBY AL-
221 PM CDT TUE APR 17 2012

...SIGNIFICANT WEATHER ADVISORY FOR WESTERN SHELBY AND CENTRAL
JEFFERSON COUNTIES UNTIL 300 PM CDT...

AT 221 PM CDT...THE NATIONAL WEATHER SERVICE WAS TRACKING A STRONG
THUNDERSTORM 6 MILES NORTHWEST OF MAYLENE...OR 7 MILES SOUTHWEST OF
HELENA...MOVING NORTH AT 25 MPH.

PEA SIZE HAIL AND WIND GUSTS UP TO 40 MPH ARE EXPECTED WITH THIS
STORM...ALONG WITH HEAVY RAIN AND FREQUENT DANGEROUS LIGHTNING.

LOCATIONS IN OR NEAR THE PATH OF THIS STORM INCLUDE...
  HELENA...
  BESSEMER...
  HOOVER...
  HUEYTOWN...
  VESTAVIA HILLS...
  HOMEWOOD...

THIS STORM MAY INTENSIFY...SO BE CERTAIN TO MONITOR LOCAL RADIO AND
TV STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS... FOR ADDITIONAL
INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.

TORRENTIAL RAIN...WHICH MAY FLOOD LOW LYING AREAS SUCH AS DITCHES AND
UNDERPASSES...IS ALSO LIKELY. DO NOT DRIVE YOUR VEHICLE ON A FLOODED
ROADWAY.

&&

LAT...LON 3354 8666 3316 8695 3318 8703 3321 8702
      3325 8703 3334 8703 3356 8702
TIME...MOT...LOC 1921Z 196DEG 22KT 3326 8695
Special weather statement, Apr 17, 2:28 PM CDT, 38 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
228 PM CDT TUE APR 17 2012

ALZ027-036-172000-
COOSA AL-TALLADEGA AL-
228 PM CDT TUE APR 17 2012

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHERN TALLADEGA AND NORTHERN
COOSA COUNTIES UNTIL 300 PM CDT...

AT 224 PM CDT...THE NATIONAL WEATHER SERVICE WAS TRACKING A STRONG
THUNDERSTORM NEAR STRICKLAND CROSSROADS...OR NEAR WEOGUFKA...MOVING
NORTHEAST AT 15 MPH.

PEA SIZE HAIL AND WIND GUSTS UP TO 40 MPH ARE EXPECTED WITH THIS
STORM...ALONG WITH HEAVY RAIN AND FREQUENT DANGEROUS LIGHTNING.

LOCATIONS IN OR NEAR THE PATH OF THIS STORM INCLUDE...
  STEWARTVILLE...
  SYLACAUGA...
  WOODSTOCK...
  GANTTS QUARRY...
  SYLACAUGA MUNICIPAL AIRPORT...

THIS STORM MAY INTENSIFY...SO BE CERTAIN TO MONITOR LOCAL RADIO AND
TV STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS... FOR ADDITIONAL
INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.

TORRENTIAL RAIN...WHICH MAY FLOOD LOW LYING AREAS SUCH AS DITCHES AND
UNDERPASSES...IS ALSO LIKELY. DO NOT DRIVE YOUR VEHICLE ON A FLOODED
ROADWAY.

&&

LAT...LON 3319 8613 3319 8618 3311 8618 3304 8630
      3303 8638 3307 8643 3324 8635 3323 8611
TIME...MOT...LOC 1928Z 220DEG 15KT 3308 8636
Local storm report, Apr 17, 2:56 PM CDT, 10 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
256 PM CDT TUE APR 17 2012

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0249 PM     HAIL             HOOVER                  33.38N 86.82W
04/17/2012  E0.50 INCH       JEFFERSON          AL   BROADCAST MEDIA

0250 PM     HAIL             SYLACAUGA               33.18N 86.26W
04/17/2012  E0.50 INCH       TALLADEGA          AL   BROADCAST MEDIA

0252 PM     HAIL             SYLACAUGA               33.18N 86.26W
04/17/2012  E1.00 INCH       TALLADEGA          AL   AMATEUR RADIO

0255 PM     HAIL             SYLACAUGA               33.18N 86.26W
04/17/2012  E1.75 INCH       TALLADEGA          AL   LAW ENFORCEMENT

&&

AG
Special weather statement, Apr 17, 3:06 PM CDT, 0 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
306 PM CDT TUE APR 17 2012

ALZ024>026-172045-
JEFFERSON AL-SHELBY AL-ST. CLAIR AL-
306 PM CDT TUE APR 17 2012

...SIGNIFICANT WEATHER ADVISORY FOR NORTHERN SHELBY...SOUTHWESTERN
ST. CLAIR AND EASTERN JEFFERSON COUNTIES UNTIL 345 PM CDT...

AT 306 PM CDT...THE NATIONAL WEATHER SERVICE WAS TRACKING A STRONG
THUNDERSTORM NEAR MEADOWBROOK...OR NEAR VESTAVIA HILLS...MOVING
NORTHEAST AT 20 MPH.

HAIL UP TO ONE-HALF INCH IN DIAMETER AND WIND GUSTS UP TO 40 MPH ARE
EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN.

LOCATIONS IN OR NEAR THE PATH OF THIS STORM INCLUDE...
  MOUNTAIN BROOK...
  IRONDALE...
  LEEDS...
  MOODY...
  TRUSSVILLE...

TORRENTIAL RAIN...WHICH MAY FLOOD LOW LYING AREAS SUCH AS DITCHES AND
UNDERPASSES...IS ALSO LIKELY. DO NOT DRIVE YOUR VEHICLE ON A FLOODED
ROADWAY.

&&

LAT...LON 3373 8660 3348 8631 3329 8677 3342 8688
TIME...MOT...LOC 2007Z 229DEG 19KT 3341 8672

19

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 17, 2:14 PM CDTAreal Flood AdvisoryBMXLamar, Marion3 hr
Apr 17, 2:21 PM CDTSpecial Weather StatementBMXShelby39 min
Apr 17, 2:28 PM CDTSpecial Weather StatementBMXCoosa32 min
Apr 17, 2:45 PM CDTSevere Thunderstorm WarningBMXClay, Talladega45 min
Apr 17, 3:17 PM CDTSpecial Weather StatementBMXClay43 min
Apr 17, 3:30 PM CDTSpecial Weather StatementBMXTalladega45 min
Apr 17, 3:35 PM CDTSevere Thunderstorm WarningBMXTalladega40 min
Apr 17, 4:10 PM CDTSpecial Weather StatementBMXCalhoun50 min

Nearby

Special Weather Statements in Alabama, 2012Every 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.