FXUS62 KCAE 050754
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
254 AM EST SAT DEC 5 2009
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE WILL MOVE ACROSS THE REGION
TODAY...PROVIDING A CHANCE OF RAIN MAINLY THIS MORNING. HIGH
PRESSURE WILL BUILD IN FOR SUNDAY. AN ACTIVE JET STREAM WILL LEAD TO
LIGHT RAIN POTENTIAL MONDAY...WITH INCREASING CHANCES TUESDAY AND
WEDNESDAY AS THE NEXT SIGNIFICANT WEATHER SYSTEM APPROACHES.
&&
.NEAR TERM /THROUGH TODAY/...
STALLED FRONT AND MAIN MOISTURE BAND REMAINS TO OUR SOUTH. AN
AREA OF LOW PRESSURE IS OVER THE EASTERN GULF OFFSHORE SW FL. THE
MODELS TAKE THIS LOW ACROSS CENT/S FL AND INTO THE ATLANTIC TODAY
WHERE IT DEVELOPS AND CONTINUES TO MOVE NE. WITH THIS TRACK...MOST
OF THE MOISTURE TRANSPORT WITH THAT SYSTEM WILL REMAIN EAST OF OUR
FORECAST AREA (FA). A STRONG UPPER DISTURBANCE IS PUSHING THROUGH
THE LOWER MISSISSIPPI VALLEY...AND WILL BE MOVING NE THROUGH OUR
REGION TODAY. AHEAD OF THE DISTURBANCE...AN AREA OF PRECIPITATION
CURRENTLY STRETCHES ACROSS ALABAMA SOUTHWARD INTO THE NORTHERN
GULF. THE AIR IS COOLER TO OUR WEST...AND SOME SNOW IS CURRENTLY
BEING REPORTED ACROSS NORTHERN AND CENTRAL ALA. FORECAST SOUNDINGS
OVER OUR FA INDICATE A SUFFICIENT DEPTH OF ABOVE FREEZING
TEMPERATURES OVER OUR FA TO THWART ANY SNOW CONCERNS. PARTIAL
THICKNESS NOMOGRAMS DO SUGGEST SOME MELTING SNOWFLAKES POSSIBLY
MIXED WITH RAIN ACROSS OUR EXTREME NW FA...BUT WITH SURFACE WET
BULB TEMPS ABOVE 40 AND SOIL TEMPS STILL IN THE 50S...THERE ARE NO
CONCERNS. MODELS SEEM TO BE TRENDING FASTER WITH THIS SYSTEM...AND
IT APPEARS MOST OF THE PRECIPITATION WILL OCCUR THIS
MORNING...MOVING EAST OUT OF THE FA DURING THE AFTERNOON.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
HIGH PRESSURE WILL BUILD IN WITH DRY AIR AND NO WEATHER CONCERNS.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
MODELS CONTINUE TO INDICATE REDEVELOPING STRONG WSW UPPER FLOW AND
EMBEDDED IMPULSES...WITH WEAK ISENTROPIC LIFT AND LIGHT PRECIP
POTENTIAL RETURNING BY MONDAY. LATEST GFS/ECWMF SPEED UP THE NEXT
APPROACHING SYSTEM A LITTLE...WITH RAIN POTENTIAL TUESDAY AND
WEDNESDAY. BOTH BRING IN HIGH PRESSURE FOR THU/FRI...WITH RETURNING
MOISTURE AGAIN BY SATURDAY.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
ISENTROPIC LIFT ASSOCIATED WITH LOW PRESSURE MOVING INTO THE AREA
FROM THE SOUTH WILL RESULT IN LOWERING CEILINGS. USED AN AVERAGE OF
THE NAM MOS AND GFS LAMP FOR THE TIMING OF IFR. EXPECT MAINLY IFR
DURING THE 09Z TO 18Z TIME FRAME. AS THE LOW LIFTS NORTH OF THE
REGION WINDS WILL BE DOWNSLOPE WITH DIMINISHING MOISTURE. USED THE
GFS MOS AND LAMP FOR THE TIMING OF IMPROVING CEILINGS AND
VISIBILITIES.
WIDESPREAD MVFR OR IFR CONDITIONS MAY OCCUR MONDAY THROUGH WEDNESDAY
ASSOCIATED WITH LOW PRESSURE MOVING BACK INTO THE REGION.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
PUBLIC...DCM
AVIATION...TTH
