Area Forecast Discussion
Issued by NWS Columbia, SC

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FXUS62 KCAE 190632
AFDCAE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
232 AM EDT FRI SEP 19 2014

.SYNOPSIS...
HIGH PRESSURE CENTERED OVER THE GREAT LAKES REGION WILL EXTEND
SOUTHWARD THROUGH THE CAROLINAS TO GEORGIA OVER THE WEEKEND. LOW
PRESSURE WILL DEVELOP OFF THE GEORGIA COAST AND LIFT NORTHEAST.
A COLD FRONT WILL BRING A CHANCE FOR SHOWERS AND THUNDERSTORMS
FOR MONDAY.

&&

.NEAR TERM /THROUGH TODAY/...
EARLY THIS MORNING...MOST OF THE FORECAST AREA WILL REMAIN DRY.
THE ONE EXCEPTION IS ACROSS THE EXTREME NORTHERN PORTIONS OF THE
CWA WHERE MODERATE TO HEAVY RAINFALL HAS BEEN OCCURRING THE PAST
SEVERAL HOURS. THIS ACTIVITY IS EXPECTED TO CONTINUE FOR THE NEXT
FEW HOURS...WITH THE POTENTIAL TO PRODUCE EVEN MORE HEAVY RAINFALL
AND POSSIBLE FLOODING ISSUES. TEMPERATURES WILL CONTINUE TO FALL
EVER SO SLOWLY...BOTTOMING OUT IN THE MIDDLE TO UPPER 60S. CAN NOT
RULE OUT SOME PATCHY FOG FORMATION TOWARDS SUNRISE.

TODAY...SHOULD STILL SEE SOME LINGERING SHOWER ACTIVITY ACROSS THE
NORTHERN CWA. A STRONG SHORT WAVE WILL MOVE OUT OF THE TENNESSEE
VALLEY REGION THIS MORNING...THEN IT IS FORECAST TO BEGIN CUTTING
OFF ACROSS THE SOUTHEASTERN STATES LATER THIS AFTERNOON AND
EVENING. MEANWHILE AT THE SURFACE HIGH PRESSURE WILL CONTINUE TO
NUDGE IN FROM THE NORTH. SLIGHTLY COLDER AIR ALOFT COUPLED WITH
AFTERNOON HEATING MAY HELP TO DEVELOP ISOLATED SHOWERS AND
THUNDERSTORMS ACROSS THE REGION DURING THE LATE AFTERNOON AND
EVENING HOURS. WITH CLOUDS ACROSS THE REGION ONCE AGAIN
TODAY...TEMPERATURES WILL ONLY REACH TO AROUND 80 DEGREES.



&&

.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
THE UPPER LOW WILL BEGIN TO FILL AND LIFT NORTHEAST ON SATURDAY.
AN AREA OF SURFACE LOW PRESSURE WILL DEVELOP OVER COASTAL GEORGIA
IN RESPONSE TO THE UPPER LOW. HIGH PRESSURE WEDGING IN FROM THE
NORTH COUPLED WITH THE DEVELOPING SURFACE LOW MOVING UP THE COAST
WILL BRING INCREASING MOISTURE AND NORTHEAST WINDS TO THE FORECAST
AREA. COLD AIR ALOFT WILL INCREASE INSTABILITY...ESPECIALLY ACROSS
THE CSRA. THE NAM MODEL INDICATED STRONGER MOISTURE
CONVERGENCE...THUS HIGHER POPS THAN THE GFS. HAVE TRENDED WITH MOS
GUIDANCE WITH HIGHER POPS...MAINLY DIURNAL...FOR THE SATURDAY
PERIOD.

HIGHS WILL BE SEVERAL DEGREES BELOW CLIMATOLOGY UNDER THE
WEDGE-LIKE SETUP WITH HIGHS IN THE UPPER 70S NORTH TO LOWER 80S
SOUTH. WENT WITH CONSENSUS FOR LOWS IN THE LOW TO MID 60S.

THE AIR MASS DRIES OUT SUNDAY AS THE H850 FLOW BECOME DOWNSLOPE.
PWAT DECEASES TO AROUND ONE INCH WITH WEAK INSTABILITY. KEPT DRY
WEATHER FOR SUNDAY WITH HIGHS IN THE LOW TO MID 80S AND LOWS STILL
IN THE LOW TO MID 60S.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
THE UPPER LEVEL TROUGH WILL LIFT NORTHEAST ACROSS THE EASTERN THIRD
OF THE NATION MONDAY THROUGH WEDNESDAY. SURFACE LOW PRESSURE WILL
MOVE EAST THROUGH SOUTHEASTERN CANADA ON MONDAY DRAGGING THE NEXT
COLD FRONT ACROSS THE FORECAST AREA. WARM AIR ADVECTION AND
INCREASING MOISTURE ARE EXPECTED AHEAD OF THE FRONT. WILL KEEP LOW
CHANCE POPS MONDAY AS THE FRONT CROSSES THE FORECAST AREA. MAX
TEMPERATURES ON MONDAY ARE EXPECTED TO REACH THE LOWER 80S NORTH TO
UPPER 80S SOUTH.

COOLER AND DRIER AIR WILL REACH THE FORECAST AREA BY TUESDAY MORNING
IN THE WAKE OF THE FRONT. MAX TEMPERATURES ON TUESDAY ARE EXPECTED
TO BE AROUND 5 TO 7 DEGREES COOLER THAN ON MONDAY. GFS PRECIPITABLE
WATER VALUES DROP DOWN TO BELOW THREE QUARTERS OF AN INCH. A LARGE
AREA OF HIGH PRESSURE WILL BUILD ACROSS THE EASTERN HALF OF THE
NATION TUESDAY INTO THURSDAY BRINGING DRY WEATHER. SHOULD SEE HIGHS
IN THE MID 70S TO LOWER 80 AND OVERNIGHT LOWS IN THE UPPER 50S TO
LOWER 60S.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
VERY TRICKY FORECAST OVERNIGHT FOR TAF SITES. NAM MODEL TRYING TO
BRING IFR/LIFR VISIBILITIES AND CEILINGS TO MANY SITES BY MORNING...WHILE
THE GFS GUIDANCE KEEPS CEILINGS GENERALLY VFR AND VISIBILITIES
MVFR. BASED ON THE AMOUNT OF MID AND HIGH LEVEL CLOUDS SHOWING UP
ON SATELLITE...AND ALSO BASED ON CURRENT METAR OBS FROM AROUND THE
REGION...HAVE GENERALLY TRENDED CLOSER TO THE MORE OPTIMISTIC GFS
GUIDANCE. EVEN SO...STILL EXPECT MVFR CONDITIONS AT PERIODS OVERNIGHT
AND TOWARDS MORNING. VFR CONDITIONS WILL RETURN TO ALL SITES BY
15Z...THEN REMAINING VFR THE REMAINDER OF THE PERIOD. ALTHOUGH
WINDS WILL BE LIGHT AND VARIABLE MOST OF THE TIME...THE GENERAL
WIND FLOW WILL BE OUT OF THE EAST.

EXTENDED AVIATION OUTLOOK...LATE NIGHT AND MORNING FOG/STRATUS
POSSIBLE THROUGH SATURDAY.

&&

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

&&

$$










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