Severe Thunderstorm Warning 286, NWS Birmingham, AL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BIRMINGHAM AL
1230 PM CDT FRI JUN 12 2009

.UPDATED...AVIATION DISCUSSION.

&&

.DISCUSSION...

SEVERAL NOTEWORTHY MESOSCALE FEATURES GOING ON THIS MORNING. A WEAK
UPPER LEVEL IMPULSE WAS PRODUCING SOME SHOWERS ACROSS WEST CENTRAL
ALABAMA. THIS FEATURE DOES NOT MUCH VERTICAL DEPTH AS IT HAS NOT
BEEN ABLE TO INITIATE ANY SURFACE BASED CONVECTION.  A OUTFLOW
BOUNDARY FROM LAST NIGHTS CONVECTION HAS PUSHED SOUTHWARD OUT OF
TENNESSEE AND NEAR A HAMILTON TO GADSDEN LINE.  THERE IS SURFACE
BASED CONVERGENCE NEAR THIS BOUNDARY AND CUMULUS HAS DEVELOPED
RAPIDLY IN THIS AREA.  THIS AREA WILL LIKELY EXPERIENCE THE FIRST
DIURNAL CONVECTION OF THE DAY.  THE MOST PROMINENT WEATHER FEATURE
IS THE MCS OVER EAST OKLAHOMA.  THIS SYSTEM WILL LIKELY BRING STORMS
INTO WEST ALABAMA LATER TODAY AND COULD BE THE PRIMARY SEVERE
WEATHER MAKER.

TEMPERATURES WILL CLIMB BACK TO AROUND 90 WITH SURFACE DEWPOINTS IN
THE LOWER 70S.  12Z BMX SOUNDING INDICATES PLENTY OF DRY AIR ALOFT
WITH DECENT LAPSE RATES 800-600MB.  SURFACE BASED CAPES ARE ALREADY
RUNNING 2500-3000 J/KG AND LIFTED INDICES NEAR -6 CELSIUS....SO AIR
MASS IS PRIMED FOR SEVERE STORMS.

58/ROSE

&&

.AVIATION...18Z TAF DISCUSSION.

SCT-BKN CUMULUS WILL DOMINATE SKY CONDS THRU 01Z.  TSTMS WILL
INCREASE IN COVERAGE THIS AFTERNOON MAINLY ACROSS NORTH ALABAMA.
OUTSIDE OF CONVECTION...VFR CONDITIONS WILL PREVAIL. AN MCS OVER
ARKANSAS WILL TRACK SOUTHEAST AND COULD AFFECT WEST ALABAMA BETWEEN
01Z AND 05Z.  HOWEVER...CONFIDENCE IS TO LOW AT THIS TIME TO INCLUDE
TSTMS IN TAFS.

&&

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

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BIRMINGHAM AL
1251 PM CDT FRI JUN 12 2009

ALZ011>015-017>050-131200-
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-
1251 PM CDT FRI JUN 12 2009

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

.DAY ONE...THIS AFTERNOON AND TONIGHT.

THERE IS A RISK OF SEVERE THUNDERSTORMS FROM 2 PM UNTIL MIDNIGHT...
GENERALLY ALONG AND NORTH OF THE LINE FROM GEIGER...TO MARION...
TO WETUMPKA...TO AUBURN. THE PRIMARY THREATS WILL BE DAMAGING
WINDS AND LARGE HAIL. ISOLATED SEVERE STORMS ARE POSSIBLE THIS
AFTERNOON GENERALLY ALONG AND NORTH OF I-20.  A MORE ORGANIZED
THREAT OF SEVERE STORMS EXISTS THIS EVENING AS A LARGE THUNDERSTORM
COMPLEX APPROACHES WEST ALABAMA THIS EVENING.  THERE IS UNCERTAINTY
AS TO WHETHER THIS SYSTEM WILL IS WEAKEN AS IT MOVES INTO
ALABAMA....BUT THERE IS A POTENTIAL FOR DAMAGING STRAIGHT LINE
WINDS WITH THIS SYSTEM.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.

ANOTHER RISK OF SEVERE THUNDERSTORMS WILL EXIST ON
SATURDAY AFTERNOON AND EVENING...ANYWHERE ACROSS THE AREA
AS AN UPPER LEVEL IMPULSE MOVES THROUGH.  THE PRIMARY THREAT
WILL BE DAMAGING WINDS.

NO OTHER HAZARDOUS WEATHER IS EXPECTED FOR THE REMAINDER OF THE
PERIOD AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

ACTIVATION OF STORM SPOTTERS AND EMERGENCY MANAGEMENT MAY BE
REQUIRED TODAY AND AGAIN ON SATURDAY.