Area Forecast Discussion
Issued by NWS Columbia, SC

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000
FXUS62 KCAE 020650
AFDCAE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
250 AM EDT THU OCT 2 2014

.SYNOPSIS...
THE PRESSURE RIDGE EXTENDING THROUGH THE FORECAST AREA WILL SHIFT
JUST OFF THE COAST THIS AFTERNOON. AN APPROACHING COLD FRONT WILL
MOVE THROUGH THE AREA LATE FRIDAY NIGHT AND EARLY SATURDAY MORNING.
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL OCCUR AHEAD OF
THE FRONT. THE COOLEST TEMPERATURES OF THE SEASON SO FAR WILL FOLLOW
THE FRONT.

&&

.NEAR TERM /THROUGH TONIGHT/...
NOCTURNAL COOLING WITH LIGHT WIND AND SUFFICIENT LOW-LEVEL
MOISTURE HAS HELPED CAUSE AREAS OF FOG EARLY THIS MORNING. HEATING
AND MIXING SHOULD DISSIPATE THE FOG BEFORE 1000 AM. THE SURFACE
RIDGE EXTENDING THROUGH THE FORECAST AREA WILL SHIFT JUST OFF THE
COAST THIS AFTERNOON. THE PRESSURE GRADIENT WILL REMAIN WEAK WITH
THE RIDGE NEAR THE AREA BUT A SOUTH TO SOUTHEAST WIND WILL BECOME
MORE DOMINATE AS THE RIDGE MOVES EASTWARD THIS AFTERNOON. THE NAM
AND GFS INDICATE BUILDING UPPER-LEVEL RIDGING TODAY. IT WILL BE
ANOTHER WARM DAY AND EXPECT HIGHS IN THE UPPER 80S TO AROUND 90.
RECORD HIGHS FOR TODAY/S DATE ARE 93 AND 95 AT AGS AND
CAE...RESPECTIVELY. THE RIDGE SHOULD KEPT THE DEEPER MOISTURE WEST
OF THE FORECAST AREA THROUGH TONIGHT. USED THE GUIDANCE CONSENSUS
FOR THE TEMPERATURE FORECAST.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY/...
THE NAM AND GFS SHOW THE COLD FRONT APPROACHING FRIDAY WITH FRONTAL
PASSAGE LATE FRIDAY NIGHT OR EARLY SATURDAY MORNING. THE GFS IS
ABOUT 6 HOURS FASTER WITH THE FRONTAL TIMING. HOWEVER...BOTH MODELS
INDICATE DEEPEST MOISTURE IN THE FORECAST AREA AHEAD OF THE FRONT
LATE FRIDAY AFTERNOON INTO THE EVENING ASSOCIATED WITH A MID-LEVEL
SHORTWAVE TROUGH. WE FORECASTED THE HIGHEST POPS DURING THAT PERIOD.
THE MODELS DISPLAY H85 WINDS 30 TO 35 KNOTS. THIS SHEAR SUPPORTS
ORGANIZED THUNDERSTORMS AND DAMAGING WIND GUSTS COULD POSSIBLY
OCCUR BUT THE CHANCE APPEARS LOW AT THIS TIME BECAUSE OF EXPECTED
WEAK INSTABILITY. THE NAM DISPLAYS SURFACE-BASED LI/S -2 TO -4.
THE WEAK INSTABILITY APPEARS REASONABLE BECAUSE THE MODELS ARE
CONSISTENT SHOWING MUCH OF THE UPPER-LEVEL LIFT STAYING WELL NORTH
OF THE FORECAST AREA. DRYING BEHIND THE FRONT SHOULD DOMINATE
SATURDAY. THE NAM AND GFS MOS INDICATE BREEZY CONDITIONS SATURDAY
WITH WINDS 15 TO 20 MPH. USED THE WARMER TEMPERATURE GUIDANCE JUST
AHEAD OF THE FRONT FRIDAY. MIXING AND CLOUDINESS ASSOCIATED WITH
THE FRONT SUPPORTED THE WARMER TEMPERATURE GUIDANCE FRIDAY NIGHT.
ALSO USED THE WARMER TEMPERATURE GUIDANCE SATURDAY. MOS IS USUALLY
TOO COOL WHEN THERE IS AN EARLY MORNING FRONTAL PASSAGE AND WE GET
OFF TO A RELATIVELY WARM START WITH DOWNSLOPE WIND.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
THE DRY AIR MASS BEHIND THE COLD FRONT WILL LIKELY DOMINATE THROUGH
MUCH OF THE MEDIUM-RANGE PERIOD. MOISTURE MAINLY ASSOCIATED WITH A
MID-LEVEL SHORTWAVE TROUGH APPEARS LIMITED TUESDAY. THE GFS AND
ECMWF MOS HAVE POPS 20 TO 30 PERCENT TUESDAY...AND LESS THAN 20
PERCENT DURING THE REST OF THE PERIOD. THE COOLEST TEMPERATURES
SHOULD BE SATURDAY NIGHT AND SUNDAY NIGHT WITH THE PRESSURE RIDGE
NEAR THE AREA. THE GFS AND ECMWF MOS SUPPORT LOWS MAINLY IN THE
MIDDLE AND UPPER 40S THOSE NIGHTS.

&&

.AVIATION /07Z THURSDAY THROUGH MONDAY/...
HIGH PRESSURE WILL BE OVER THE AREA THROUGH THE TAF PERIOD.

MOSTLY CLEAR SKIES AND NEAR CALM WIND WILL AID THE DEVELOPMENT OF
FOG OVERNIGHT...PARTICULARLY AT KAGS AND KOGB. ALREADY SEEING A
DECLINE IN VSBY AT AGS AND OGB. GFS LAMP METEOGRAM AND GFS LAMP
PROBABILITY GUIDANCE SEEMS TO DOWNPLAY THREAT OF DENSE FOG FOR BOTH
AGS AND OGB.

SHOULD SEE AT LEAST PATCHY MVFR FOG DEVELOP BEFORE SUNRISE AS THE
NOCTURNAL JET WEAKENS. HAVE INDICATED MVFR/IFR FOG AT OGB AND
IFR/LIFR AT AGS THROUGH 13Z. FORECASTED MVFR FOG AT KCAE/KCUB/DNL
AROUND SUNRISE. CONDITIONS SHOULD IMPROVE TO VFR AROUND 13Z. WINDS
WILL BE MAINLY FROM THE SOUTH DURING THE AFTERNOON WITH SCATTERED
CLOUDS 4 KFT TO 6 KFT.

EXTENDED AVIATION OUTLOOK...FOG AND LOW CLOUDS COULD BRING
RESTRICTIONS EARLY FRIDAY MORNING. RESTRICTIONS POSSIBLE IN SHOWERS
AND THUNDERSTORMS FRIDAY AFTERNOON AND FRIDAY NIGHT AS A COLD FRONT
CROSSES THE REGION. POST FRONTAL GUSTY WINDS COULD DEVELOP SATURDAY.

&&

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

$$





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