105 FXUS62 KCAE 040639 AFDCAE AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE COLUMBIA SC 139 AM EST MON MAR 4 2013 .SYNOPSIS... WEAK HIGH PRESSURE WILL BUILD INTO THE REGION OVERNIGHT THROUGH MONDAY. THE NEXT LOW PRESSURE SYSTEM WILL APPROACH FROM THE WEST MONDAY NIGHT SPREADING INCREASING CHANCES OF RAIN OVER THE AREA FOR TUESDAY THROUGH WEDNESDAY AFTERNOON. THE LOW WILL DEPART ON WEDNESDAY EVENING WITH HIGH PRESSURE RETURNING FOR THURSDAY AND FRIDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... CLEAR SKIES OVERNIGHT AND BOUNDARY LAYER DECOUPLING EXPECTED. SO WITH MODERATELY GOOD RADIATIONAL COOLING CONDITIONS...TEMPERATURES SHOULD FALL INTO THE MID TO UPPER 20S. && .SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY NIGHT/... HIGH PRESSURE WILL REMAIN OVER THE REGION TODAY...THEN IT IS FORECAST TO BEGIN MOVING OUT OF THE AREA AS WE MOVE INTO TUESDAY. AS THE HIGH MOVES OFF TO THE SOUTHEAST...SURFACE WINDS ARE EXPECTED TO TURN OUT OF THE SOUTH TUESDAY. THIS SHOULD ALLOW FOR AN INCREASE IN LOW-LEVEL MOISTURE...ALONG WITH WARMING TEMPERATURES ON TUESDAY. READINGS IN THE 60S ARE ONCE AGAIN EXPECTED TO RETURN. IN ADDITION TO THE WARMER TEMPS...ANOTHER SURFACE LOW AND UPPER TROUGH WILL BE DEVELOPING OFF TO THE WEST OF THE REGION...AND THEN TRACKING EASTWARD THROUGH THE DAY TUESDAY. EXPECTING THE MORNING HOURS ON TUESDAY TO REMAIN DRY...BUT BY TUESDAY AFTERNOON THE MODELS ARE INDICATING AN INCREASING CHANCE FOR RAINFALL ACROSS THE WESTERN COUNTIES. THIS AREA OF LOW PRESSURE AND ITS ASSOCIATED COLD FRONT WILL SWEEP THROUGH THE REGION TUESDAY NIGHT INTO WEDNESDAY MORNING. AT THIS TIME IT APPEARS AS IF THIS WILL BE THE TIME FRAME IN WHICH WE SHOULD HAVE THE BEST CHANCE FOR SEEING RAINFALL. CAN NOT RULE OUT AN ISOLATED THUNDERSTORM OR TWO ALONG AND AHEAD OF THE MAIN FRONT...BUT STILL NOT CONFIDENT ENOUGH TO PLACE IN THE FORECAST. ONE ISSUE STILL REVOLVES AROUND THE TIMING OF THE SYSTEM. BETWEEN THE GFS AND THE ECMWF...THE GFS APPEARS TO BE THE FASTER OF THE TWO MODELS RIGHT NOW. IN GENERAL...WENT WITH A BLEND OF THE TWO FOR THE TIMING AND MOVEMENT OF THE PRECIP. THE COLD FRONT WILL BE PUSHING EAST OF THE CWA DURING THE MORNING HOURS ON WEDNESDAY...TAKING BEST RAINFALL CHANCES ALONG WITH IT. FOR NOW...THE BEST CHANCE FOR RAIN EARLY WEDNESDAY MORNING...THEN RAIN CHANCES WILL CONTINUE TO DIMINISH FROM THE SOUTHWEST AS THE MORNING AND AFTERNOON PROGRESS. && .LONG TERM /THURSDAY THROUGH MONDAY/... DRY WEATHER LOOKS TO DOMINATE THROUGH THE LONG TERM PERIOD AS WE MOVE INTO SUNDAY. AT THE SURFACE...HIGH PRESSURE WILL BE BUILDING INTO THE REGION THROUGH THE PERIOD...WHILE ALOFT FORECAST MODELS SHOWING A BUILDING RIDGE PATTERN ACROSS THE EASTERN REGIONS AS WE MOVE INTO THE WEEKEND. SURFACE FLOW ON THURSDAY WILL BE OUT OF THE NORTH...WHICH WOULD INDICATE COLD ADVECTION PATTERN. HOWEVER WITH MORE SUNSHINE EXPECTED ON THURSDAY THAN WHAT IS EXPECTED FOR WEDNESDAY...EXPECTING AFTERNOON TEMPS TO ACTUALLY BE A FEW DEGREES WARMER THAN WEDNESDAY. AS WE MOVE TOWARDS AND EVEN INTO THE WEEKEND...AFTERNOON HIGHS ARE EXPECTED TO MODERATE EACH DAY. HIGHS ON SATURDAY SHOULD REACH THE MID 60S...THEN ON SUNDAY THEY APPEAR AS IF THEY WILL BE ABLE TO FINALLY REACH 70 DEGREES IN MANY LOCATIONS. && .AVIATION /07Z MONDAY THROUGH FRIDAY/... HIGH CONFIDENCE IN VFR CONDITIONS THROUGH THE PERIOD. HIGH PRESSURE BUILDING INTO THE AREA PROVIDING A DRY AIRMASS. POTENTIAL FOR FOG EARLY THIS MORNING REMAINS TOO LOW TO INCLUDE IN TAFS DUE TO DRY AIRMASS AND LIGHT NORTHWEST WIND. HIGH CLOUDS INCREASING TODAY. NORTHWEST WIND THIS MORNING BACKING TO SOUTHWEST BY 05/00Z. .EXTENDED AVIATION OUTLOOK... INCREASING CONFIDENCE IN MVFR CONDITIONS FROM MIDDAY TUESDAY INTO TUESDAY NIGHT AS A DEVELOPING LOW PRESSURE SYSTEM CROSSES THE AREA. STRONG AND GUSTY NORTHWEST WINDS POSSIBLE WEDNESDAY IN THE WAKE OF THE LOW PRESSURE SYSTEM. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$ 77