Area Forecast Discussion
Issued by NWS Birmingham, AL

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000
FXUS64 KBMX 281242
AFDBMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BIRMINGHAM AL
642 AM CST SAT FEB 28 2015

.UPDATE...
FOR 12Z AVIATION.

&&

.DISCUSSION...

MID TO HIGH LEVEL CLOUDS MOVING ACROSS THE AREA THIS MORNING WITH
WEAK RETURNS SHOWING UP ON RADAR...ASSOCIATED WITH THE CLOUD
COVER. FAIRLY DRY AIR BELOW THE CLOUD DECK...AND NO REPORTS OF ANY
PRECIP REACHING THE GROUND. MID LEVEL FLOW REMAINS ZONAL
TODAY...AS SURFACE HIGH PRESSURE BUILDS OFF THE ATLANTIC COAST AND
EXTENDS SOUTHWARD...STRENGTHENING THE WEDGE ACROSS GEORGIA AND
INTO EAST CENTRAL ALABAMA. WEDGE IS SLOW TO BUILD IN TODAY...AND
KEPT HIGH TEMPS ACROSS THE EAST IN THE LOWER 50S...BUT IF EASTERLY
FLOW DEVELOPS QUICKER...TEMPS WILL LIKELY NEED TO BE ADJUSTED
DOWNWARD. A WEAK IMPULSE IN ZONAL FLOW WILL PASS TO OUR SOUTH
TODAY...BUT WILL PULL MOISTURE NORTHWARD. THIS COMBINED WITH THE
LIFT PROVIDED BY THE WEDGE WILL BE ENOUGH FOR A FEW SHOWERS TO
DEVELOP ACROSS THE FAR SOUTHEAST THIS AFTERNOON. THIS ACTIVITY
WILL SPREAD NORTHWARD TONIGHT ACROSS EAST CENTRAL ALABAMA. EXPECT
RAIN TO BE VERY LIGHT.

AS A SHORTWAVE DROPS ACROSS THE GREAT LAKES SUNDAY AND
MONDAY...WEAK RIDGING AMPLIFIES ACROSS THE SOUTHERN US...PUSHING
THE MAIN DISTURBANCE TRACK TO OUR NORTH. WITH SOUTHERLY TO
SOUTHWESTERLY FLOW IN PLACE...MOISTURE RETURNS TO THE AREA. THE
WEDGE KEEPS A HOLD ON THE EAST...PROVIDING ANOTHER LIFTING
MECHANISM. WILL KEEP A MENTION OF LOW POPS IN THE FORECAST FOR
SUNDAY...BUT BETTER RAIN CHANCES WILL BE TO OUR NORTH...CLOSER TO
A FRONT DROPPING THROUGH THE OHIO RIVER VALLEY. FRONT MAKES IT TO
CENTRAL ALABAMA ON MONDAY...BUT BETTER FORCING IS WELL DISPLACED
TO THE NORTH AND WILL NOT INCLUDE THUNDER. FRONT WASHES OUT IN
ZONAL FLOW...AS SURFACE HIGH PRESSURE QUICKLY BUILDS ACROSS THE
OHIO RIVER VALLEY.

SOUTHERLY FLOW RETURNS MONDAY NIGHT AS THE RIDGE AXIS SHIFTS
EASTWARD AND THE LONGWAVE TROUGH AMPLIFIES OVER THE SOUTHWESTERN
CONUS. A SHORTWAVE AHEAD OF THE MAIN TROUGH WILL EJECT
NORTHEASTWARD ACROSS THE PLAIN...PULLING MOISTURE NORTHWARD
THROUGH THE MISSISSIPPI RIVER VALLEY AND REESTABLISHING
SOUTHWESTERLY FLOW ACROSS THE SOUTHEASTERN CONUS. ON ITS HEELS...A
STRONG TROUGH WILL DROP OUT OF CENTRAL CANADA AND PHASE WITH THE
TROUGH OVER THE SOUTHWESTERN CONUS. THESE FEATURES RESULT IN AN
AMPLIFIED TROUGH AND SURFACE LOW THAT CROSS THE CENTRAL
PLAINS...DRAGGING A COLD FRONT ACROSS THE MID AND LOWER
MISSISSIPPI RIVER VALLEY. MOISTURE POOLING WILL PRIMARILY BE TO OUR
NORTH TUESDAY...BUT CLOSE ENOUGH TO KEEP POPS IN THE FORECAST. THE
COLD FRONT WILL PUSH INTO NORTHWEST ALABAMA TUESDAY NIGHT AND
THROUGH CENTRAL ALABAMA ON WEDNESDAY. MODELS CONTINUE TO SHOW MOST
OF THE FORCING BEHIND THE FRONT WITHIN THE COOLER AIRMASS. AS
A STRONG ARCTIC HIGH DIVES SOUTHWARD BEHIND THE FRONT...IT IS
POSSIBLE THAT COLDER AIR WILL SPREAD INTO THE AREA BEFORE RAIN
MOVES TO THE EAST. WILL CONTINUE TO MENTION A WINTRY MIX WEDNESDAY
NIGHT AND THURSDAY MORNING AS MOISTURE PUSHES OUT OF THE AREA. TOO
EARLY TO DISCUSS IMPACTS...BUT WILL MONITOR TRENDS IN COLD AIR
UNDERCUTTING MOISTURE IN TIME FOR ANY FROZEN PRECIP.

14


&&

.AVIATION...
12Z TAF DISCUSSION.

VFR CONDITIONS ARE EXPECTED FOR ALL TERMINALS THROUGH THE DAY
TODAY...WITH BROKEN CIGS AROUND 10 TO 15K FEET EXPECTED TO
PERSIST. SURFACE WINDS WILL PREVAIL OUT OF THE EAST BETWEEN 7 TO
10 KNOTS. AS MOISTURE INCREASES FROM THE EAST OVERNIGHT
TONIGHT...IFR CIGS WILL LIKELY MOVE INTO ALL OF CENTRAL ALABAMA
AFTER 06Z AND HAVE GONE AHEAD AND INCLUDED THE LOW CIGS INTO THE
PLANNING PERIOD.

56/GDG

&&

.PRELIMINARY POINT TEMPS/POPS...
GADSDEN     52  38  52  43  55 /  10  20  30  60  50
ANNISTON    54  40  57  44  59 /  10  20  30  60  50
BIRMINGHAM  56  41  55  46  57 /   0  20  30  60  60
TUSCALOOSA  59  43  55  48  58 /  10  10  20  60  60
CALERA      57  43  57  47  59 /   0  20  20  60  60
AUBURN      53  41  55  46  64 /  10  20  30  50  40
MONTGOMERY  57  44  61  49  67 /  10  20  30  50  50
TROY        57  43  61  49  70 /  10  20  30  40  40

&&

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

&&

$$






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