Area Forecast Discussion
Issued by NWS Birmingham, AL

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FXUS64 KBMX 161634 AAA
AFDBMX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BIRMINGHAM AL
1034 AM CST TUE DEC 16 2014

.UPDATE...
MORNING UPDATE.

&&

.DISCUSSION...

THE COLD FRONT IS NOW SOUTH OF CENTRAL ALABAMA THIS MORNING.
DESPITE BREEZY WEST TO NORTHWESTERLY WINDS...NOT MUCH COLD
ADVECTION BEHIND THIS SYSTEM TO BRING TEMPERATURES DOWN BELOW
CLIMO VALUES FOR THIS TIME OF THE YEAR. MOISTURE ASSOCIATED WITH
THE UPPER LEVEL SHORT WAVE WILL KEEP CLOUD COVER ACROSS THE NORTH
THROUGH THE DAY. THIS WILL CURB WARMING SOMEWHAT...AND EXPECT
LOWER 50S ACROSS THE NORTH TO MID 60S ACROSS THE SOUTHEAST.

14

&&

.AVIATION...
12Z TAF DISCUSSION.

RAIN SHOWERS AND LOW CLOUDS ASSOCIATED ALONG/AHEAD OF FRONT IN
SOUTHEAST WILL BE MOVING OUT. ACROSS THE NORTH TERMINALS...(I-20
CORRIDOR) MAY SEE SOME WRAP AROUND CLOUDINESS AT TCL/BHM/EET/
ASN/ANB TODAY BUT MORE THAN LIKELY WILL BE MORE SCATTERED IN
NATURE AND ABOVE 3KFT WITH THE LOWER CIGS FURTHER TO THE NORTH.
WINDS WILL BE A LITTLE GUSTY AT TIMES THIS MORNING WITH TIGHTER
GRADIENTS IN VICINITY OF THE FRONT...BUT SHOULD TAPER DOWN THIS
AFTERNOON...WITH IMPROVING CONDITIONS TONIGHT.

08/MK


&&

.PREV DISCUSSION...
/ISSUED 723 AM CST TUE DEC 16 2014/

A COLD FRONT IS CURRENTLY LOCATED ALONG THE I-59 CORRIDOR EARLY THIS
MORNING WITH SHOWERS CONTINUING TO MOVE ACROSS CENTRAL ALABAMA AHEAD
OF THE FRONT. CURRENT WATER VAPOR IMAGERY INDICATES A CLOSED UPPER
LEVEL LOW MOVING ACROSS NORTHERN ILLINOIS INTO THE GREAT LAKES.
TEMPERATURES OVER THE NEXT FEW HOURS WILL BEGIN TO DROP ACROSS THE
WEST WITH WEAK COLD AIR ADVECTION. SHOWERS SHOULD COME TO AN END
SHORTLY AFTER SUNRISE AS THE FRONT PROGRESSES ACROSS THE REMAINDER
OF CENTRAL ALABAMA BY 15Z. MOST OF THE AREA WILL HAVE PLENTY OF
INSOLATION TODAY TO OVERCOME THE WEAK COLD AIR ADVECTION. FURTHER TO
THE NORTH...WRAP AROUND CLOUDS LOOK TO MOVE IN ALONG AND NORTH OF
I-20 WITH TEMPERATURES HAVING A HARD TIME MAKING IT OUT OF THE LOW
50S. FURTHER SOUTH WITH INSOLATION...TEMPERATURES SHOULD WARM INTO
THE UPPER 50S AND LOW 60S. TEMPERATURES TODAY WILL BE HIGHLY
DEPENDENT UPON HOW FAR SOUTH THE WRAP AROUND CLOUDS PROGRESS AND
FURTHER UPDATES TO TEMPERATURES AND CLOUD COVER MAY BE NEEDED
THROUGHOUT THE DAY.

UPPER LEVEL FLOW IS FORECAST TO BE ZONAL LATE TODAY INTO WEDNESDAY
WITH ONLY WEAK COLD AIR ADVECTION BEHIND THE FRONT. THIS SHOULD LEAD
TO TEMPERATURES TO AROUND NORMAL FOR THIS TIME OF YEAR WITH LOWS IN
THE 30S AND HIGHS IN THE 50S AND 60S. AN UPPER LEVEL TROUGH MOVES OUT
OF THE DESERT SOUTHWEST INTO THE CENTRAL AND SOUTHERN PLAINS LATE
WEDNESDAY INTO THURSDAY. THIS SYSTEM WILL LEAD TO SOME LIFT ACROSS
THE AREA BUT MOISTURE REMAINS LIMITED WITH PW VALUES GENERALLY UNDER
0.75 INCHES THROUGH THURSDAY NIGHT. THEREFORE...HAVE ONLY A CHANCE
TO SLIGHT CHANCE OF SHOWERS WITH BEST CHANCES ACROSS THE
NORTHWESTERN COUNTIES WHERE THE BEST LIFT AND MOISTURE WILL BE.

ON FRIDAY...AN UPPER LEVEL TROUGH MOVES OUT OF THE DESERT SOUTHWEST
AND PIVOTS ACROSS THE SOUTHERN PLAINS. CYCLOGENESIS WILL TAKE PLACE
ALONG THE NATURAL BAROCLINIC ZONE ALONG THE TEXAS GULF COAST.
ISENTROPIC UPGLIDE AHEAD OF THE UPPER LEVEL SYSTEM WILL HELP TO
SATURATE THE ATMOSPHERE WITH WIDESPREAD RAIN CHANCES RETURNING TO
THE FORECAST FOR CENTRAL ALABAMA ON FRIDAY. THE OPERATIONAL RUNS OF
THE GEM...ECMWF AND GFS STILL DIFFER BUT ARE BEGINNING TO TREND
TOWARDS A CONSENSUS. THE GEM STILL FAVORS A SOUTHERN TRACK OF THE
LOW JUST OFF THE GULF COAST FRIDAY NIGHT INTO SATURDAY. THE ECMWF
HAS ALSO TRENDED FURTHER SOUTH AND WEAKER SINCE LAST NIGHTS RUN WITH
LOW TRACKING FROM NEAR SLIDELL...TO MOBILE...TO DOTHAN. THE GFS HAS
TRENDED FURTHER SOUTH AND WEAKER AS WELL WITH A SURFACE LOW TRACKING
JUST A TOUCH NORTH OF THE ECMWF. IN ADDITION...THE GFS ENSEMBLE MEAN
LOOKS LIKE IT WOULD BE NEAR THE OPERATIONAL RUN. REGARDLESS OF THE
TRACK...MOISTURE WILL BE PLENTIFUL WITH PW VALUES INCREASING TO 1.25
INCHES LATE FRIDAY INTO EARLY SATURDAY. DUE TO THIS AND BETTER MODEL
CONSISTENCY WENT AHEAD FRIDAY INTO EARLY SATURDAY WITH THE HIGHEST
POPS FRIDAY NIGHT INTO SATURDAY MORNING. WITH THESE HIGHER
PRECIPITATION CHANCES EXPECT LOWS ON SATURDAY MORNING WILL BE WARMER
THAN MOS GUIDANCE SUGGESTS AND CURRENTLY HAVE LOWS SATURDAY MORNING
IN THE MID 40S TO LOW 50S. DUE TO THE WEAKER AND FURTHER SOUTH
TRACK...WENT AHEAD AND REDUCED THE MENTION OF THUNDERSTORMS TO ONLY
THE SOUTHERN ROW OF COUNTIES OR SO. IN ADDITION...THE WEAKER SYSTEM
WILL NOT PULL IN AS MUCH COLD AIR IN ITS WAKE AND INCREASED
TEMPERATURES THROUGHOUT MUCH OF THE EXTENDED PORTION OF THE
FORECAST. TEMPERATURES WILL BE NEAR NORMAL FOR THIS TIME OF THE YEAR
WITH HIGHS MAYBE A TOUCH BELOW NORMAL. HIGHS WILL GENERALLY BE IN
THE 50S WITH LOWS IN THE 30S.

05/MA

&&

.PRELIMINARY POINT TEMPS/POPS...
GADSDEN     54  32  53  33  53 /  10   0   0  10  20
ANNISTON    56  33  55  35  55 /  10   0   0  10  10
BIRMINGHAM  55  35  53  37  53 /  10   0   0  10  20
TUSCALOOSA  58  34  55  37  54 /  10   0   0  10  20
CALERA      57  35  55  37  55 /  10   0   0  10  10
AUBURN      60  37  57  38  59 /  10   0   0  10  10
MONTGOMERY  63  34  59  37  61 /  10   0   0  10  10
TROY        64  34  59  37  62 /  10   0   0  10   0

&&

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

&&

$$






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