Area Forecast Discussion
Issued by NWS Columbia, SC

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000 FXUS62 KCAE 262325 AFDCAE AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE COLUMBIA SC 725 PM EDT THU MAR 26 2015 .SYNOPSIS... A COLD FRONT WILL SLOWLY SHIFT SOUTH THROUGH OUR REGION TONIGHT AND FRIDAY. COLDER AIR WILL FILTER IN BEHIND THE FRONT. NEAR OR BELOW FREEZING TEMPERATURES EXPECTED LATE SATURDAY NIGHT AND EARLY SUNDAY MORNING...AS THE CENTER OF A COOL CANADIAN HIGH PRESSURE AIR MASS SETTLES IN OVERHEAD. A FRONT IS EXPECTED TO MOVE THROUGH MONDAY PROVIDING A SLIGHT CHANCE OF SHOWERS. SOME MOISTURE RETURN EXPECTED MID TO LATE NEXT WEEK. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... AMPLIFIED UPPER LEVEL TROUGH FROM THE GREAT LAKES REGION SOUTHWEST ACROSS THE SOUTHERN PLAINS WILL CONTINUE TO MOVE EAST AND DRIVE A STRONG COLD FRONT TOWARD THE REGION TONIGHT. AT THE MOMENT...AIR MASS IS RELATIVELY DRY WITH SHALLOW LOW LEVEL MOISTURE. MODEL K-INDEX VALUES REMAIN LOW THROUGH THE EARLY EVENING. IT APPEARS THAT CHANCE OF SHOWERS WILL REMAIN QUITE LOW THROUGH THE EARLY EVENING AS MOISTURE LIMITED AND MID LEVEL CAP REMAINS. MOISTURE FLUX WILL INCREASE DURING THE EVENING AND OVERNIGHT AS UPPER TROUGH MOVES CLOSER TO THE REGION. STRONG MID LEVEL SHORT WAVE IN THE NORTHERN GULF OF MEXICO WILL TRACK NORTHEAST OVERNIGHT AND ENHANCE UPPER LEVEL LIFT AND REGION UNDER FAVORABLE ENTRANCE REGION 250MB JET-MAX. CHANCE OF SHOWERS INCREASING AFTER 06Z FROM WEST TO EAST AS FRONT APPROACHES AND MOISTURE/LIFT INCREASES. RAIN MAY BE DELAYED IN THE SOUTHEAST MIDLANDS UNTIL PRE-DAWN HOURS. INSTABILITY APPEARS WEAK WITH SURFACE BASED CAPE BELOW 500 J/KG. STRONG DEEP LAYER SHEAR HOWEVER AND THREAT FOR A FEW EMBEDDED THUNDERSTORMS LATE TONIGHT AS COLD FRONT APPROACHES. LOW THREAT SEVERE THUNDERSTORMS. MOS CONSENSUS USED FOR OVERNIGHT MINIMUM TEMPERATURES...IN THE LOW 50S NORTH TO THE LOW 60S SOUTHEAST. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/... COLD FRONT...AND ASSOCIATED SHOWER AND ISOLATED THUNDERSTORM ACTIVITY...IS EXPECTED TO MOVE SLOWLY SOUTH THROUGH OUR FORECAST AREA LATE TONIGHT AND FRIDAY. COLDER AIR WILL FILTER INTO THE REGION BEHIND THE FRONT...AND MOST PRECIP EXPECTED TO TREND SE OUT OF OUR FA DURING THE DAY FRIDAY...THOUGH A PERIOD OF LIGHT SHOWER ACTIVITY POSSIBLE BEHIND THE FRONT FRI NT AS STRONG UPPER TROUGH MOVES THROUGH. SECONDARY UPPER AND SURFACE TROUGH TO MOVE THROUGH SATURDAY...BUT A DRY ATMOSPHERE IS EXPECTED TO PRECLUDE ANY PRECIP. COOL CANADIAN HIGH PRESSURE CENTER WILL BUILD INTO THE REGION LATE SATURDAY NIGHT. APPEARANCE OF GOOD RADIATIONAL COOLING CONDITIONS PROVIDES CONCERN FOR NEAR OR BELOW FREEZING TEMPERATURES...AND POSSIBLY FROST...LATE SAT NT/EARLY SUN. FREEZE WATCHES AND WARNINGS MAY BE REQUIRED. GROWERS AND OTHER INTERESTS SHOULD CLOSELY MONITOR. && .LONG TERM /SUNDAY THROUGH THURSDAY/... WEAKENING UPPER TROUGH TO REMAIN ALONG THE EAST COAST SUNDAY. A FRONT IS PROGGED TO COME THROUGH MON/MON NT. SOME TIMING DIFFERENCES NOTED BETWEEN GFS AND ECMWF. GFS FASTER WITH THE FRONT AND INDICATING LESS MOISTURE WITH IT. ECMWF SLOWER TO MOVE IT THROUGH WITH APPEARANCE OF BETTER MOISTURE. ENSEMBLE AVERAGE POPS AROUND 20 PERCENT DURING THAT TIME FRAME. WILL INTRODUCE SLIGHT CHANCE POPS. HIGH PRESSURE BEHIND FRONT TO MOVE IN BY TUE. SOME MODEL DIFFERENCES CONTINUE NEXT WEEK...WITH GFS FASTER WITH MOISTURE RETURN WED...WITH ECMWF HOLDING OFF UNTIL THU. ENSEMBLE POPS IN THE SLIGHT CHANCE RANGE WED AND CHANCE THU. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... SOUTHWESTERLY FLOW AND MIXING AHEAD OF AN APPROACHING COLD FRONT WILL RESULT IN MAINLY VFR CONDITIONS THIS EVENING. THE RAIN CHANCE APPEARS LOW EARLY TONIGHT WITH SHALLOW MOISTURE AND WEAK INSTABILITY PLUS A MID-LEVEL CAP. THE GREATER SHOWER CHANCE WILL BE AFTER 06Z. THE MODELS SHOW CEILING RESTRICTIONS RETURNING LATE TONIGHT. BELIEVE MAINLY MVFR CONDITIONS WILL OCCUR BUT A PERIOD OF IFR CONDITIONS MAY OCCUR AROUND SUNRISE IN HEAVIER SHOWERS. THE GFS AND NAM MOS PLUS SREF GUIDANCE INDICATE THE LOWEST CEILINGS DURING THAT PERIOD. THUNDERSTORMS ARE POSSIBLE...BUT WITH LIMITED INSTABILITY AND AN UNFAVORABLE DIURNAL TIMING BELIEVE THE CHANCE IS TOO LOW TO INCLUDE IN THE TERMINAL FORECASTS AT THIS TIME. SOUTHWEST WINDS AHEAD OF THE FRONT TONIGHT WILL VEER TO NORTHWEST AND NORTH BEHIND THE FRONT FRIDAY. THE NAM BUFKIT MOMENTUM TRANSFER TOOL SUPPORTS GUSTS NEAR 20 KNOTS BEHIND THE FRONT. THE MODELS SHOW LINGERING LOW-LEVEL MOISTURE BEHIND THE FRONT DURING THE DAY FRIDAY...BUT MIXING SHOULD HELP HOLD UP CEILINGS. AN AVERAGE OF THE GFS AND NAM MOS PLUS SREF GUIDANCE SUPPORTED MAINLY MVFR CONDITIONS. EXTENDED AVIATION OUTLOOK...RESTRICTIONS ARE POSSIBLE INTO FRIDAY NIGHT ASSOCIATED WITH LINGERING LOW-LEVEL MOISTURE BEHIND THE COLD FRONT. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$

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