FXUS64 KBMX 252318
AFDBMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BIRMINGHAM AL
251 PM CST FRI DEC 25 2009

.UPDATE...AVIATION DISCUSSION.

&&

.DISCUSSION...

WITH THE COLD FRONT OUT OF THE STATE AND THE CLOUDS FOLLOWING NOT 
TOO FAR BEHIND...THINGS SHOULD BEGIN TO QUIET DOWN FOR THE NEXT 
COUPLE OF DAYS.  SKIES ARE ALREADY BEGINNING TO CLEAR ACROSS OUR 
WESTERN COUNTIES...AND THIS TREND WILL CONTINUE ACROSS THE REST
OF THE CWA THROUGH THE REMAINDER OF THE AFTERNOON AND EARLY
EVENING HOURS. THE SURFACE PRESSURE GRADIENT ALSO CONTINUES TO
RELAX AS YESTERDAYS STRONG LOW PRESSURE SYSTEM PULLS OFF TO THE
NORTH...SO OTHER THAN A COUPLE OF GUSTS TO 15 OR 17 MPH FOR THE
NEXT HOUR OR TWO...WE SHOULD GET LIGHT TO CALM WINDS OVERNIGHT.

HIGH PRESSURE WILL TRICKLE INTO THE REGION OVERNIGHT ALLOWING FOR 
SKIES TO REMAIN CLEAR TOMORROW...THOUGH TEMPERATURES WILL BE FAIRLY
COOL WITH THE COLD AIR ADVECTION THE NORTHERN GULF STATES WILL
SEE. TEMPERATURES SHOULD BOTTOM OUT AOB 30 DEGREES AREA WIDE
TONIGHT.

THE REMAINDER OF THE FORECAST LOOKS LIKE ITS GOING TO BE DOMINATED 
BY THIS VERY ACTIVE SOUTHERN JET STREAM.  MODELS HAVE WAVERED BACK 
AND FORTH WITH SOME POSSIBLE MOISTURE DURING THE DAY ON SUNDAY... 
BUT THE NAM/GFS/SREF HAVE REALLY COME IN LINE WITH ONE ANOTHER IN 
REGARDS TO A SOUTHWESTERLY SHORTWAVE THAT DEVELOPS ALONG THE 
SOUTHERN PERIPHERY OF THE LONGWAVE TROUGH OVER THE GREAT LAKES.  THE 
CORRESPONDING SURFACE LOW SHOULD STAY SOUTH OF US...LIKELY KEEPING 
THINGS DRY IN CENTRAL ALABAMA.  WILL KEEP A SLIGHT CHANCE OF SOME 
LIGHT RAIN SOUTH OF INTERSTATE 85 ON SUNDAY OTHERWISE LOOK FOR A DRY 
WEEKEND.

THE ACTION PICKS BACK LATE TUESDAY AND INTO THE DAY ON WEDNESDAY AS 
ANOTHER UPPER LEVEL TROUGH DIGS INTO THE SOUTHWEST UNITED STATES AND 
ACROSS MEXICO. THE INTERESTING THING WITH THIS...GFS ENSEMBLES ARE 
IN PRETTY GOOD AGREEMENT WITH THIS TROUGH DIGGING INTO THE SOUTHWEST 
U.S.  THIS AMPLIFICATION SHOULD BE RESPONSIBLE FOR TWO SURFACE LOWS 
THAT WILL MOVE INTO OR CLOSE TO THE NORTHERN GULF STATES.  THE FIRST 
IS A SHORTWAVE OUT AHEAD OF THE MAIN TROUGH THAT WILL KICK UP THE 
FIRST GULF LOW.  THIS ONE SHOULD STAY SOUTH OF THE AREA LIKE 
SUNDAY'S...BUT THIS WILL BEGIN THE FIRST OF TWO MAIN FORECAST 
CHALLENGES THIS WEEK.  COLD AIR WILL ALREADY BE IN PLACE ACROSS 
CENTRAL ALABAMA...ESPECIALLY WEDNESDAY MORNING. FOR NOW... WITH 
LOW-TO-MEDIUM CONFIDENCE IN THE LONG RANGE...HAVE INTRODUCED A
CHANCE OF RAIN OR SNOW THROUGH EARLY MORNING HOURS ON WEDNESDAY.

AFTER THAT ACTIVITY MOVES EAST OF THE STATE...THE MAIN TROUGH DIGS 
INTO THE SOUTH. ANOTHER SURFACE LOW DEVELOPS...AND THIS TIME...WITH
SOME FAIRLY STRONG CAA ADVECTION BEHIND IT...WE SEE ANOTHER SHOT
AT SOME WINTER PRECIPITATION IN THE FRIDAY/SATURDAY TIMEFRAME.
NORMALLY...I DO NOT LIKE TO INTRODUCE WINTER PRECIPITATION THIS
FAR INTO THE FORECAST FOR ALABAMA...BUT IF THERES GOING TO BE
MOISTURE IN THE AIR AND COLD TEMPERATURES TO BOOT... 

AFTER ALL...IT IS AN EL NINO WINTER.

27

&&

.AVIATION...00Z TAF DISCUSSION.

ONLY A FEW 3000 FOOT CLOUDS REMAIN AT ANB AND SHOULD DIMINISH BY 
03Z.  VFR CONDITIONS ARE EXPECTED AT ALL SITES THROUGH TOMORROW AS 
SURFACE HIGH PRESSURE BUILDS IN FROM THE WEST.  WINDS WILL BE FROM 
THE WEST TO NORTHWEST AT LESS THAN 5 KNOTS.

12/SIRMON

&&

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

&&

$$

27/16