000
FXUS64 KBMX 202338
AFDBMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BIRMINGHAM AL
538 PM CST FRI NOV 20 2009

.UPDATE...AVIATION DISCUSSION.

.DISCUSSION...

A SURFACE LOW PRESSURE SYSTEM IS BEGINNING TO TAKE SHAPE OVER
EASTERN TEXAS. THIS SYSTEM WILL CONTINUE TO TRACK ALONG THE
NORTHERN GULF THROUGH THE WEEKEND WHICH WILL BRING RAIN CHANCES
INTO THE AREA. BIG QUESTION MARKS WITH THIS SYSTEM AS FAR AS RAIN
CHANCES GO. THE GFS IS THE MOST AGGRESSIVE WANTING TO BRING RAIN
INTO THE AREA AS EARLY AS TONIGHT. HOWEVER...NAM AND SREF ARE NOT
NEARLY AS FAST. IN FACT...THE CONSENSUS IS FOR A SLOWER SOLUTION
WHEN ADDING THE ENSEMBLE MODELS. GIVEN THAT A STRONG HIGH
PRESSURE IS IN PLACE AND DRY CONDITIONS STILL PREVAIL...WILL BASE
THE FORECAST ON THE SLOWER SOLUTION.

WHAT THIS MEANS IS THAT RAIN SHOULD HOLD UP UNTIL SATURDAY
MORNING...WITH THE HEAVIER AMOUNTS NOT OCCURRING UNTIL MUCH LATER
IN THE AFTERNOON. IN FACT...THE LATEST SREF WANTS TO BRING THE
MAIN BULK OF THE RAIN SATURDAY NIGHT AND CONTINUING THROUGH
SUNDAY. DRY CONDITIONS WILL THEN RETURN LATE SUNDAY INTO MONDAY.

A WEAK COLD FRONT WILL MOVE THROUGH THE AREA ON WEDNESDAY.
MOISTURE WILL BE LIMITED WITH THIS FRONT...SO EXPECT RAIN CHANCES
TO REMAIN QUITE LOW.

THE WEAK FRONT WILL THEN BE OVERTAKEN ON THURSDAY WHEN A MUCH
STRONGER FRONT MOVES THROUGH GIVING WAY TO COOLER TEMPERATURES AND
DRY CONDITIONS FOR THE END OF NEXT WEEK.

10/ARM

.AVIATION...00Z TAF DISCUSSION.

HIGH CLOUDS WILL CONTINUE TO MOVE ACROSS THE AREA TONIGHT...WITH
LIGHT TO CALM WINDS. WITH CONSIDERABLE CLOUDINESS...DO NOT EXPECT
WIDESPREAD BR/VIS PROBLEMS OVERNIGHT. ALTHOUGH...CAN NOT RULE OUT A
FEW HOURS OF BCFG AT TCL. AS A SURFACE LOW APPROACHES FROM THE WEST
TOMORROW...EXPECT LIGHT RAIN SHOWERS TO SPREAD INTO CENTRAL
ALABAMA...FROM SOUTHWEST TO NORTHEAST...AND CONTINUE THROUGH THE
AFTERNOON AND INTO SATURDAY EVENING.

14

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