900 
FXUS64 KBMX 062126
AFDBMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BIRMINGHAM AL
326 PM CST TUE MAR 6 2012

.DISCUSSION...

WITH SURFACE HIGH PRESSURE SLIPPING OFF TO THE EAST...OUR LOW
LEVEL FLOW IS BECOMING INCREASINGLY EAST TO SOUTHEASTERLY. THIS
WILL START TO DRAW SOME GULF AND ATLANTIC MOISTURE INTO THE AREA
OVER THE NEXT FEW DAYS. THIS WILL IN TURN BRING MORE MIDDLE TO LOW
LEVEL CLOUDINESS TO THE AREA...AND ALSO CONTINUE THE GRADUAL
WARMING TREND THAT BEGAN THIS AFTERNOON. BUT ANOTHER BIG UPPER
LEVEL TROUGH IS LURKING OUT WEST...AND THE EVENTUAL
DEVELOPMENT/MOVEMENT OF THAT TROUGH WILL DETERMINE THE TIMING OF
THE NEXT ROUND OF IMPACT WEATHER FOR CENTRAL ALABAMA.

12Z MODEL DATA SUGGESTS THAT WE SHOULD STAY DRY AT LEAST THROUGH
THURSDAY. BY THURSDAY NIGHT...A COLD FRONT IS FORECAST TO DROP
INTO THE TN AND LOWER MS VALLEYS...INCREASING THE CHANCES FOR RAIN
IN THE NORTHWEST. FROM THERE...THINGS START TO GET TRICKY. THE
MODELS STALL THE FRONT OUT ACROSS THE SOUTHEAST STATES...ALTHOUGH
EACH HAS A DIFFERENT VERSION ON EXACTLY WHERE. THE CENTER OF THE SURFACE
HIGH PUSHING THE FRONT ALONG SLIPS OVER THE TOP...AND EVENTUALLY
GETS INTO WHAT COULD BECOME A PRIME CAD WEDGE LOCATION IN THE
NORTHEAST STATES. MEANWHILE...THE MODELS ARE ALSO HAVING THEIR
USUAL DIFFICULT TIME TRYING TO FIGURE OUT HOW EXACTLY THE UPPER
LEVEL SHORTWAVE TROUGH(S) LIFT OUT FROM OUT WEST INTO THE EASTERN
HALF OF THE COUNTRY. THIS ALL LEADS TO A VERY LOW CONFIDENCE
FORECAST FOR THE UPCOMING WEEKEND. THERE'S BOUND TO BE SEVERAL
WAVES OF RAIN FROM FRIDAY THROUGH ON THROUGH EARLY NEXT
WEEK...WITH PERIODS OF MOSTLY CLOUDY BUT RAINFREE CONDITIONS IN
BETWEEN. TRYING TO PINPOINT THE RAINY AND RAINFREE TIMES IS QUITE
PROBLEMATIC AT THIS POINT...SO AN ENSEMBLE APPROACH WAS TAKEN WITH
THE FORECAST. ONE THING THE MODELS DO GENERALLY AGREE ON IS THAT
EVEN WITH SOME INSTABILITY AVAILABLE TO CAUSE SOME THUNDERSTORMS...
THERE DOES NOT APPEAR TO BE ENOUGH SHEAR PRESENT TO ORGANIZE THEM
INTO SEVERE STORMS.

/61/

&&

.AVIATION...
18Z TAF DISCUSSION.

SURFACE HIGH PRESSURE REMAINS CENTERED OFF THE NC/VA COAST AND WILL 
SLOWLY CONTINUE TO MOVE EAST. LOCALLY...WINDS WILL REMAIN OUT OF THE 
EAST TO SOUTHEAST...AND BE GUSTY AT TIMES DUE TO AN INCREASED 
PRESSURE GRADIENT. WINDS IN THE MIXED LAYER ARE EXPECTED TO BE RANGE 
FROM 10-20KTS TODAY. LOW LEVEL WINDS INCREASE OVERNIGHT AS WARM AIR 
ADVECTION REGIME IS IN FULL SWING...WITH WINDS AROUND 2K FT AT 
140-170 DEGREES AT 30-35KTS. DO NOT ANTICIPATE ANY LLWS PROBLEMS 
GIVEN SURFACE WINDS SHOULD REMAIN AT 5-8KTS OVERNIGHT. 

ELEVATED SURFACE WINDS OVERNIGHT WILL ALSO PREVENT ANY WIDESPREAD 
FOG DEVELOPMENT. THERE IS WEAK ISENTROPIC LIFT BOTH TO OUR WEST AND 
EAST...WHICH WILL INCREASE LOW LEVEL MOISTURE. THE BEST CHANCE FOR 
MVFR CIGS WILL BE AT ANB AS LOW CIGS TRY TO SPREAD WESTWARD ACROSS 
GA.  

14

&&

.PRELIMINARY POINT TEMPS/POPS...
GADSDEN     43  69  52  73  57 /   0   0   0  10  30 
ANNISTON    46  68  53  72  59 /   0   0   0  10  20 
BIRMINGHAM  49  70  56  73  60 /   0   0   0  10  20 
TUSCALOOSA  49  73  55  75  61 /   0   0   0  10  20 
CALERA      49  70  55  73  60 /   0   0   0  10  20 
AUBURN      47  68  53  72  58 /   0   0   0   0  10 
MONTGOMERY  49  73  55  75  60 /   0   0   0   0  10 
TROY        48  72  53  74  59 /   0   0   0   0  10 

&&

.BMX WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 6 PM FOR ALL COUNTIES.

&&

$$