Area Forecast Discussion
Issued by NWS Columbia, SC

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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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