FXUS62 KCAE 040801
AFDCAE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
301 AM EST FRI DEC 4 2009

.SYNOPSIS...
LOW PRESSURE WILL DEVELOP ALONG A STALLED FRONTAL BOUNDARY TO OUR 
SOUTH TONIGHT AND SATURDAY...SPREADING MOISTURE INTO OUR REGION.  
HIGH PRESSURE WILL BUILD IN SUNDAY. AN ACTIVE JET STREAM WILL LEAD 
TO LIGHT RAIN POTENTIAL MONDAY AND TUESDAY. A COLD FRONT IS EXPECTED 
TO MOVE THROUGH WEDNESDAY. 

&&

.NEAR TERM /THROUGH TODAY/...
CURRENT SURFACE ANALYSIS INDICATES FRONT STRETCHED WELL TO OUR 
SOUTH...WITH HIGH PRESSURE CENTER WELL TO OUR NW. UPPER TROUGH
EXTENDS FROM THE GREAT LAKES SW INTO THE FOUR CORNERS REGION. 
RELATIVELY DRY AIR WILL REMAIN IN PLACE TODAY. A STRONG SW UPPER
FLOW OVER OUR REGION WILL LEAD TO INCREASING HIGH TO MID LEVEL
CLOUDINESS PUSHING INTO OUR REGION.

&&

.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
MODELS INDICATE MAIN UPPER TROUGH ENERGY TO SWING AROUND TO 
THE MISS VALLEY BY TONIGHT...AND INDICATE A PAIR OF WEAK LOWS 
DEVELOPING ALONG THE FRONT OVER THE GULF AND ATLANTIC. LATEST MODEL 
RUNS ARE INDICATING GULF LOW TO REMAIN WEAK WHILE THE ATLANTIC LOW 
WILL DEVELOP AND MOVE NE. THIS APPEARS TO KEEP THE BEST MOISTURE 
TRANSPORT MAINLY TO OUR EAST...WITH PERHAPS UPPER LIFT PROVIDING
THE MAIN MECHANISM FOR ANY PRECIPITATION OVER OUR FORECAST AREA
(FA). LATEST MODEL RUNS ARE NOW TRENDING DOWN ON POP AND QPF FOR
OUR FA. SINCE MODELS ARE SHOWING SOME RUN TO RUN
INCONSISTENCY...CONFIDENCE ON SPECIFICS IS REDUCED AND WILL ONLY
TWEAK POPS DOWN A TAD...GENERALLY BLENDING ONGOING FORECAST WITH
MOS CONSENSUS ON POPS. IT STILL DOES NOT APPEAR THAT WE WILL HAVE
PRECIPITATION TYPE CONCERNS IN OUR FA. SUFFICIENTLY COLD AIR WILL
NOT BE IN PLACE AHEAD OF TIME. SOIL TEMPS ARE STILL QUITE
HIGH...AND EARLY DECEMBER IS A LITTLE EARLY CLIMATOLOGY WISE FOR
WINTER PRECIP. ARRAY OF DATA INCLUDING FORECAST SOUNDINGS AND
PARTIAL THICKNESS NOMOGRAM ALL POINT TO JUST LIQUID RAIN FOR OUR
FA.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
GFS/ECMWF CONTINUE TO INDICATE SURFACE HIGH PRESSURE BUILDING IN 
SUNDAY. LATEST RUNS INDICATE REDEVELOPING STRONG SW UPPER FLOW AND 
EMBEDDED IMPULSES...WITH WEAK ISENTROPIC LIFT AND LIGHT PRECIP
POTENTIAL RETURNING PERHAPS AS EARLY AS SUNDAY NIGHT...CONTINUING
UNTIL A FRONT MOVES THROUGH LATE WEDNESDAY.

&&

.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
DRYING HAS OCCURRED BEHIND A COLD FRONT. EXPECT MAINLY VFR 
CONDITIONS. THE MAIN FORECAST PROBLEM IS THE FOG POTENTIAL. HIGH 
SOIL MOISTURE AND CROSS-OVER TEMPERATURES SUPPORT EARLY MORNING FOG. 
HOWEVER...THE MODELS SHOW A LITTLE MIXING AND MAINTAIN TEMPERATURE
DEW POINT TEMPERATURE SPREADS. KEPT A VFR FORECAST...EXCEPT
FORECASTED A PERIOD OF MVFR FOG AT OGB BECAUSE OF THE ADDED
MOISTURE ASSOCIATED WITH THE RIVER VALLEY AND A SLIGHTLY LESS
PRESSURE GRADIENT INDICATING A LITTLE LESS MIXING. THIS WAS
SUPPORTED BY THE GFS LAMP GUIDANCE. ISENTROPIC LIFT AND MOISTURE
WILL BE ON THE INCREASE LATE IN THE TAF PERIOD WITH LOWERING
CEILINGS.

EXTENDED OUTLOOK...LOW PRESSURE MOVING INTO THE REGION WILL LIKELY 
BRING WIDESPREAD MVFR OR LOWER CONDITIONS LATE FRIDAY NIGHT AND 
SATURDAY.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.

&&

$$
PUBLIC...DCM
AVIATION...TTH