Area Forecast Discussion
Issued by NWS Columbia, SC

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000
FXUS62 KCAE 202051
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
451 PM EDT SUN APR 20 2014

.SYNOPSIS...
LOW PRESSURE OFF THE SOUTH CAROLINA COAST WILL MOVE A LITTLE
FARTHER OUT TO SEA TONIGHT AS A RIDGE OF HIGH PRESSURE APPROACHES
FROM THE WEST. THIS RIDGE WILL EXTEND THROUGH THE FORECAST AREA
MONDAY. A WEAK COLD FRONT WILL REACH THE AREA TUESDAY AFTERNOON OR
EVENING.

&&

.NEAR TERM /THROUGH TONIGHT/...
LOW PRESSURE OFFSHORE MOVING SLOWLY AWAY FROM THE AREA. SATELLITE
SHOWING CLEAR SKY ACROSS THE PIEDMONT...BUT CONSIDERABLE CLOUDINESS
IN THE EAST. NORTH WINDS...WARM ADVECTION RESULTING IN
MILD TEMPERATURES MOST OF THE AREA DESPITE CLOUDS. MOST AREAS
IN THE MID 60S TO LOWER 70S LATE THIS AFTERNOON.

MODELS SUGGESTING DECREASING CLOUDS OVERNIGHT ALTHOUGH THEY MAY
LINGER IN THE EAST MIDLANDS AND PEE DEE AT LEAST THROUGH MIDNIGHT.
BUT AS LOW PRESSURE MOVES AWAY EXPECT MOISTURE ADVECTION TO SHIFT
TO THE COAST AND DRIER AIR TO SPREAD ACROSS AREA. GUSTY WINDS THIS
AFTERNOON WILL BE DIMINISHING AS SURFACE PRESSURE GRADIENT
CONTINUES TO WEAKEN. TEMPERATURE GUIDANCE SHOWS LARGE SPREAD FOR
MINIMUM TEMPERATURES TONIGHT. DEW POINTS EXPECTED TO BE LOW BUT
MIXING IN THE BOUNDARY LAYER AND POSSIBLE CLOUDS SHOULD KEEP
TEMPERATURES FROM FALLING TOO FAST. MOS HAS COOL BIAS SO WILL GO
ABOVE MOS CONSENSUS FOR LOWS.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
MONDAY THROUGH MONDAY NIGHT...STACKED LOW PRESSURE WILL CONTINUE
TRACKING FURTHER EAST INTO THE ATLANTIC ON MONDAY AS AN UPPER
RIDGE BUILDS OVER THE EASTERN CONUS. HIGH PRESSURE WILL RIDGE INTO
THE FORECAST AREA AT THE SURFACE PROVIDING MOSTLY SUNNY SKIES FOR
MONDAY AFTERNOON. MAXIMUM TEMPERATURES WILL RETURN TO NEAR NORMAL
IN THE LOWER 70S NORTH TO UPPER 70S SOUTH. CLOUDS WILL INCREASE
MONDAY NIGHT INTO TUESDAY MORNING AS AN UPPER TROUGH SHIFTS EAST
ACROSS THE CENTRAL CONUS AND APPROACHES THE REGION FROM THE WEST.
OVERNIGHT LOWS ARE FORECAST IN THE LOWER 50S.

TUESDAY THROUGH TUESDAY NIGHT...SURFACE LOW PRESSURE WILL MOVE EAST
TOWARD NEW ENGLAND ON TUESDAY DRAGGING A WEAK COLD FRONT ACROSS
THE AREA TUESDAY AFTERNOON/EVENING. DESPITE THE FAVORABLE DIURNAL
TIMING OF THE FRONT FOR THUNDERSTORMS...MOISTURE AND CONVERGENCE
APPEAR LIMITED. THE H85 FLOW WILL BE WESTERLY WITH GULF MOISTURE
MAINLY CUT OFF. MODEL PRECIPITABLE WATER VALUES MAX OUT AROUND 1.3
INCHES DURING THE 18Z-00Z TIME FRAME. NAM AND GFS BUFKIT SOUNDINGS
INDICATE ONLY WEAK INSTABILITY. SURFACE SOUTHWESTERLY FLOW WILL
INCREASE AHEAD OF THE FRONT PROMOTING WARM AIR ADVECTION ACROSS
THE AREA. GUIDANCE WAS CONSISTENT SHOWING AFTERNOON HIGHS MAINLY
IN THE LOWER 80S.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
WEDNESDAY AND THURSDAY ARE FORECAST TO BE WARM AND DRY AS AN UPPER
RIDGE BUILDS OVER THE EASTERN CONUS AND HIGH PRESSURE DOMINATES AT
THE SURFACE. EXPECT NEAR NORMAL MAX TEMPERATURES IN THE UPPER 70S
TO LOWER 80S. THE NEXT SYSTEM WILL AFFECT THE AREA FRIDAY INTO
SATURDAY. LOW PRESSURE MOVING EAST OVER THE NORTHEASTERN CONUS
WILL PUSH SURFACE HIGH PRESSURE OFFSHORE AND DRAG ANOTHER WEAK
FRONTAL BOUNDARY ACROSS THE AREA. CONFIDENCE REMAINS TOO LOW TO
INCREASE POPS AT THIS TIME DUE TO A LACK OF DEEP MOISTURE
ASSOCIATED WITH THIS SYSTEM. ABOVE NORMAL TEMPERATURES ARE
FORECAST FRIDAY THROUGH SUNDAY WITH HIGHS IN THE LOWER 80S AND
LOWS IN THE 50S.

&&

.AVIATION /21Z SUNDAY THROUGH FRIDAY/...
LOW PRESSURE SYSTEM OFFSHORE WILL SLOWLY MOVE NORTHEAST OVERNIGHT.
HIGH CONFIDENCE FOR VFR CONDITIONS THROUGH THE PERIOD. BROKEN TO
OVERCAST STRATO-CUMULUS ACROSS THE TAF SITES WILL ERODE DURING THE
EVENING. NORTH-NORTHEAST WINDS AROUND 10 KTS WITH GUSTS TO AROUND 20
KTS...DIMINISHING AS PRESSURE GRADIENT WEAKENS BY THIS EVENING.

.EXTENDED AVIATION OUTLOOK...THERE IS A CHANCE FOR MVFR OR LOWER
CONDITIONS IN CONVECTION TUESDAY AFTERNOON AND EVENING AS A COLD
FRONT CROSSES THE REGION.

&&

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

$$





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