804 
FXUS64 KBMX 181540
AFDBMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BIRMINGHAM AL
1040 AM CDT MON MAR 18 2013

.UPDATE...
FOR MORNING DISCUSSION.

&&

.DISCUSSION...

TODAY LOOKS LIKE IT COULD BE THE STORY OF 2 OR 3 DIFFERENT TALES.  
WE START OUT THIS MORNING WITH AMPLE CLOUD COVER AND SCATTERED 
SHOWERS ACROSS A LARGE PORTION OF CENTRAL ALABAMA AS WELL AS THE 
MAIN ONGOING SITUATION...THE SQUALL LINE THAT HAS DEVELOPED IN 
NORTHEAST MISSISSIPPI. AS EXPECTED...THE MORNING CLOUD COVER IS 
HAMPERING THE DEVELOPMENT OF SFC BASED INSTABILITY...BUT THE SQUALL 
LINE DOES HAVE THE ENERGY FROM THE PARENT SURFACE LOW IN SOUTHERN 
KENTUCKY WITH WHICH TO WORK.  THE LINE SHOULD REMAIN ELEVATED BUT 
WILL CARRY A LOW-END HAIL AND DAMAGING WIND THREAT.   THIS IS 
EXPECTED TO CHANGE HOWEVER AS WE MOVE INTO THE AFTERNOON HOURS.  
MODEL GUIDANCE SUPPORTED BY WATER VAPOR SATELLITE IMAGERY ARE STILL 
SUGGESTING DRY AIR WILL WORK INTO CENTRAL ALABAMA ALOFT AND WE COULD 
STILL SEE SOME MIXING OUT OF THE CLOUDS CURRENTLY IN PLACE.  IF THIS 
DOES OCCUR...A GOOD PORTION OF THE AREA COULD SEE SFC BASED CAPES IN 
THE 1000-1750 J/KG RANGE.  WHEN COUPLED WITH INCREASING MID-LEVEL 
LAPSE RATES AND VEERING SURFACE WINDS...THIS COMBINATION COULD SPELL 
SOME FAIRLY LARGE HAIL AND POTENTIALLY DAMAGING WINDS WITH ANY STORM 
THAT TAPS INTO THAT ENERGY.  IF YOU DO SEE CLEARING IN YOUR AREA AND 
THE SUN COMES OUT...THEN THAT WILL INCREASE YOUR CHANCE FOR A SEVERE 
THUNDERSTORM WATCH TO BE EXTENDED TO YOU AS THE ENVIRONMENT WILL 
RIPEN FOR SEVERE POTENTIAL THIS AFTERNOON AND EVENING. PROPER 
ENVIRONMENTAL CONDITIONS FOR SEVERE WEATHER ARE EXPECTED TO DECREASE 
AS WE MOVE TOWARDS THE MIDNIGHT HOUR TONIGHT. 

UPDATES ARE OUT.

27  

&&

.AVIATION...
12Z TAF DISCUSSION.

LOW CLOUDS JUST ABOUT ENCOMPASSING ALL TAF SITES. A FEW AREA WILL 
SEE A BRIEF WINDOW OF IMPROVEMENT BUT WENT WITH PREDOMINATE LOW MVFR 
CLOUDS NORTH AND IFR SOUTH THROUGH 15 TO 16Z. 

SHOWERS WILL CONTINUE TO DEVELOP THIS MORNING FOLLOWED BY 
THUNDERSTORMS AFTER MIDDAY AND THROUGH THE AFTERNOON HOURS. DUE TO 
THE UNSTABLE CONDITIONS THAT WILL BE IN PLACE...WENT AHEAD AND ADDED 
IN VCTS TO ALL TAFS THROUGH THE EVENING HOURS. CURRENT WINDS FROM 
THE SOUTHEAST WILL GRADUALLY SHIFT TO THE SOUTHWEST ON MONDAY 
AFTERNOON...AND COULD BECOME GUSTY UPWARDS TO 20 KNOTS AT TIMES. 
MODELS ARE HINTING THAT WE MAY HAVE A WINDOW FROM 21Z NORTH TO 3Z 
SOUTH IN WHICH CONDITIONS DRY AND IMPROVE TO VFR CEILINGS BETWEEN 
THE INITIAL LINE OF AFTERNOON THUNDERSTORMS AND THE FRONT ITSELF. 
GIVEN THE UNCERTAINTIES OF THE TIMING STUCK WITH PREDOMINATE MVFR 
AND VCTS UNTIL THE FRONT CAN ACTUALLY WORK THROUGH. MVFR LIKELY 
BEHIND THE FRONT UNTIL THE CLEARING CAN OCCUR TUESDAY MORNING. 

&&

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

&&

$$