FXUS64 KBMX 042346
AFDBMX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BIRMINGHAM AL
544 PM CST THU DEC 4 2008

.UPDATED...00Z AVIATION DISCUSSION.

&&

.DISCUSSION...RATHER ACTIVE LATE FALL/EARLY WINTER WEATHER PATTERN
WILL CONTINUE FOR THE NEXT SEVEN DAYS. FORECAST CONFIDENCE IS
AVERAGE OR BETTER UNTIL MONDAY...WITH A BIT MORE UNCERTAINTY IN
THE TUESDAY THROUGH THURSDAY TIME FRAME NEXT WEEK.

EXPECT A FAIRLY RAPID CHANGE IN CONDITIONS LATE THIS AFTERNOON AND
EVENING...AS STRONG HIGH PRESSURE SINKING INTO THE LOWER MIDWEST
QUICKLY PUSHES LINGERING LOW CLOUDS AND PATCHY DRIZZLE OUT OF THE
AREA. PRELIM POPS FOR TONIGHT LISTED BELOW ARE NOT FINAL BY ANY
MEANS...AND WILL MAKE LAST MINUTE ADJUSTMENTS DOWNWARD BEFORE
ISSUANCE. SKIES ARE ALREADY CLEARING IN FAR NORTHWESTERN MARION
COUNTY...AND THE SHARP CLEARING LINE WILL BE WORKING THROUGH
TUSCALOOSA AND BIRMINGHAM EARLY IN THE EVENING. WITH CLEAR SKIES
AND DRY AIR...EXPECT TEMPS TO DROP QUICKLY IN THE NORTHWEST. TEMPS
LAST NIGHT WERE IN THE TEENS IN MISSOURI...AND THAT AIR MASS WILL
BE GLANCING BY OUR NORTH. WILL TAKE THE LOW SIDE OF GUIDANCE
OVERNIGHT.

IN THE ACTIVE FLOW...AS A STRONG UPPER LEVEL RIDGE BUILDS ON THE
WEST COAST...AN INCONSEQUENTIAL TROUGH WILL PASS THROUGH THE AREA
TOMORROW AND THE FLOW WILL BECOME MORE NORTHWESTERLY. A CLIPPER
SYSTEM WILL PASS BY TO THE NORTH ON SATURDAY...AND ANOTHER COLD
HIGH PRESSURE SYSTEM WILL BUILD IN BEHIND A DRY COLD FRONT. THE
UPPER FLOW WILL BE A BIT DIRTY...WITH PATCHES OF CLOUDS TRANSITING
IN THE FLOW.

THE PATTERN WILL BEING TO MORPH AGAIN FAIRLY RAPIDLY BY LATE IN
THE WEEKEND AND INTO NEXT WEEK...AS THE WESTERN RIDGE BREAKS DOWN.
ENERGY COMING OFF THE NORTHERN PACIFIC WILL SPILL DOWN INTO THE
GREAT PLAINS...AND ANOTHER UPPER LEVEL TROUGH WILL BEGIN TO TAKE
SHAPE. MONDAY NIGHT INTO TUESDAY...MODELS BEGIN TO DIVERGE FAIRLY
SIGNIFICANTLY. GFS WANTS TO RAM OVERRUNNING RAINS ACROSS THE
ENTIRE AREA MONDAY NIGHT...WHILE THE EURO/GEM ALL OFFER
SIGNIFICANTLY LESS AGGRESSIVE SOLUTIONS. SINCE GFS HAS BROKEN RUN
TO RUN CONSISTENCY HERE...WILL BACK DOWN FROM MEX GUIDANCE ON POPS
AND ONSET OF PRECIP MONDAY NIGHT...AND BEGIN TO TIGHTEN UP A
GRADIENT OF POPS FROM HIGH CHANCE WEST TO SLIGHT CHANCE EAST.

THIS THEN CASTS UNCERTAINTY FURTHER INTO THE PERIOD...FOR THE
REMAINDER OF TUESDAY...AND THROUGH THE DAY WEDNESDAY AND RIGHT ON
INTO NEXT THURSDAY. WHILE THE GFS SOLUTION WOULD BRING THE BACK
EDGE OF THE SYSTEM THROUGH THE AREA BY LATE WEDNESDAY...THE
EURO HOLDS ON THROUGH LATE THURSDAY WITH A VERY WET SOAKING. GFS
HINTS AT A POSSIBLE COASTAL LOW DEVELOPMENT...WHICH MAY PINCH OFF
POPS/QPF FROM THE NORTH...WHILE THE EURO HOLDS BACK WITH THE UPPER
LOW AND GOES NEGATIVE TILT...WITH PLENTY OF WARM UNSTABLE AIR
WORKING NORTHWARD...WHICH COULD POTENTIALLY BRING STRONG OR BETTER
THUNDERSTORMS TO THE AREA. IN THE WAKE OF SUCH UNCERTAINTY...WILL
TREND FROM CURRENT FORECAST TOWARDS MEX GUIDANCE ON WEDNESDAY...
THEN HANG ON TO SLIGHT CHANCE POPS WEDNESDAY NIGHT INTO THURSDAY
FOR NOW. WILL STAY CLOSE TO MEX TEMPS FOR THIS UNCERTAIN TIME...
AND HOPE FOR BETTER CONSISTENCY BY TOMORROW.

JD/81

&&

.AVIATION...00Z TAF DISCUSSION.

THE RAIN ASSOCIATED WITH A COLD FRONT HAS ENDED ACROSS THE
AREA...LEAVING LOW CEILINGS AND PATCHY DRIZZLE BEHIND. THE CLEARING
LINE IS NEARING TCL AND BHM AT THIS TIME...AND WILL CONTINUE TO MOVE
SOUTHEAST OVERNIGHT...WITH CEILINGS RISING QUICKLY BEHIND THE
CLEARING LINE. EXPECT IFR CEILINGS AT ALL TERMINALS PRIOR TO
CLEARING...WHICH IS EXPECTED BY 02Z AT TCL AND BHM...03Z AT
EET...AND 04Z AT ANB. CLEARING AT MGM AND TOI WILL OCCUR BETWEEN
07-08Z...WITH PATCHY DZ BR CONTINUING FOR THE NEXT SEVERAL HOURS.

ONCE CLOUDS MOVE OUT...EXPECT VFR CONDITIONS THRU THE REMAINDER OF
THE FORECAST PERIOD.

14

&&

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

&&

$$

81/81/14






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