Alert archive / Alabama / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 381, NWS Birmingham, AL

July 12, 2009Chilton County, Coosa County, Shelby County, Alabama

NWS Birmingham, AL issued this severe thunderstorm warning at Jul 12, 2009, 2:41 PM CDT for Chilton County, Coosa County, Shelby County, Alabama. It was in force for 34 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Jul 12, 2009, 2:41 PM CDT (19:41 UTC)
Expired: Jul 12, 2009, 3:15 PM CDT
In force: 34 min
Issued by: NWS Birmingham, AL
Area: Storm-based polygon

Counties Chilton County, AL, Coosa County, AL, Shelby County, AL

The radar

The Birmingham radar (KBMX), 27 km from the middle of the area, began a volume at 19:42 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, 7.7 hours before the alert went out and 29 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: 885 J/kg
Mixed-layer CIN: -31 J/kg
Mixed-layer LCL: 813 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: 63 m²/s²
0-3 km storm-relative helicity: 126 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning 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 severe thunderstorm warning went out at Jul 12, 11:15 AM CDT, 3 hours 26 minutes earlier.

Area forecast discussion, Jul 12, 11:15 AM CDT, 3 hours 26 minutes before

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Hazardous weather outlook, Jul 12, 8:43 AM CDT, 5 hours 58 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BIRMINGHAM AL
843 AM CDT SUN JUL 12 2009

ALZ011>015-017>050-131328-
AUTAUGA-BARBOUR-BIBB-BLOUNT-BULLOCK-CALHOUN-CHAMBERS-CHEROKEE-
CHILTON-CLAY-CLEBURNE-COOSA-DALLAS-ELMORE-ETOWAH-FAYETTE-GREENE-HALE-
JEFFERSON-LAMAR-LEE-LOWNDES-MACON-MARENGO-MARION-MONTGOMERY-PERRY-
PICKENS-PIKE-RANDOLPH-RUSSELL-SHELBY-ST CLAIR-SUMTER-TALLADEGA-
TALLAPOOSA-TUSCALOOSA-WALKER-WINSTON-
843 AM CDT SUN JUL 12 2009

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

.DAY ONE...TODAY AND TONIGHT.

THE DEVELOPMENT OF STRONG THUNDERSTORMS WILL BE POSSIBLE AFTER 12 PM
MAINLY ALONG AND NORTH OF INTERSTATE 59.  THESE STORMS COULD
CARRY INTO THE EVENING HOURS WHERE THE MAIN AREAS OF CONCERN WILL
LIKELY BE ALONG AND SOUTH OF INTERSTATE 59. THE MAIN THREATS IN BOTH
CASES WILL BE HEAVY RAINFALL...COPIOUS AMOUNTS OF LIGHTNING AND WIND
GUSTS TO 50 MPH.

ADDITIONAL THUNDERSTORM DEVELOPMENT WILL BE POSSIBLE PRIOR TO
SUNRISE MONDAY MORNING AS A FRONT NEARS THE NORTHERN PORTIONS OF
CENTRAL ALABAMA.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY.

STRONG TO SEVERE THUNDERSTORMS WILL BE POSSIBLE ON MONDAY AS A
FRONT MOVES THROUGH CENTRAL ALABAMA. THE MAIN THREAT FROM THESE
STORMS WILL BE HEAVY RAINS AND POTENTIALLY DAMAGING WIND.

ON TUESDAY STRONG STORMS WILL ONCE AGAIN BE POSSIBLE ESPECIALLY
DURING THE AFTERNOON HOURS. THESE STORMS COULD PRODUCE LOCALLY
HEAVY RAINFALL AND WIND GUSTS TO 45 MPH.

.SPOTTER INFORMATION STATEMENT...

ACTIVATION OF STORM SPOTTERS AND EMERGENCY MANAGEMENT PERSONNEL MAY
BE NEEDED ON MONDAY.

12/SIRMON

In the hours before

Special weather statement, Jul 12, 1:24 PM CDT, 1 hour 17 minutes before

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Special weather statement, Jul 12, 2:04 PM CDT, 37 minutes before

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Special weather statement, Jul 12, 2:10 PM CDT, 31 minutes before

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Special weather statement, Jul 12, 2:28 PM CDT, 13 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
228 PM CDT SUN JUL 12 2009

ALZ025-122000-
SHELBY-
228 PM CDT SUN JUL 12 2009

...SIGNIFICANT WEATHER ALERT FOR SHELBY COUNTY UNTIL 300 PM CDT...

AT 227 PM CDT...THE NATIONAL WEATHER SERVICE IS TRACKING A STRONG
THUNDERSTORM NEAR COLUMBIANA...MOVING SOUTHEAST AT 10 MPH.

PEA SIZE HAIL...WINDS UP TO 40 MPH...FREQUENT CLOUD TO GROUND
LIGHTNING...AND HEAVY DOWNPOURS ARE EXPECTED WITH THIS STORM.

* LOCATIONS IN OR NEAR THE PATH INCLUDE...
  COLUMBIANA.
  SHELBY.
  BEESWAX AT LAY LAKE.
  AL 145 AND CR 46.
  SPRING CREEK AT LAY LAKE.

STAY TUNED TO NOAA WEATHER RADIO...COMMERCIAL RADIO...OR YOUR LOCAL
TELEVISION STATIONS FOR LATER STATEMENTS AND POSSIBLE WARNINGS
CONCERNING THIS WEATHER SITUATION.

17/KLAWS

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 12, 3:03 PM CDT	Severe Thunderstorm Warning	BMX	Autauga	27 min
Jul 12, 4:21 PM CDT	Severe Thunderstorm Warning	BMX	Etowah, St. Clair	39 min
Jul 12, 5:32 PM CDT	Severe Thunderstorm Warning	BMX	Greene, Sumter	28 min
Jul 12, 5:48 PM CDT	Severe Thunderstorm Warning	BMX	Jefferson	27 min
Jul 12, 6:15 PM CDT	Areal Flood Advisory	BMX	Jefferson	2 hr
Jul 12, 6:31 PM CDT	Severe Thunderstorm Warning	BMX	Jefferson, Shelby	29 min

Nearby

Severe Thunderstorm Warnings in Alabama, 2009 Every severe thunderstorm warning in 2009

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.