Area Forecast Discussion
Issued by NWS Columbia, SC

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000
FXUS62 KCAE 220537
AFDCAE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
1237 AM EST SAT NOV 22 2014

.SYNOPSIS...
A WEAK DRY COLD FRONT IS NOW SOUTH OF THE AREA...WITH COOL DRY
HIGH PRESSURE BUILDING BACK INTO THE REGION INTO SATURDAY.
MOISTURE RETURN EXPECTED SUNDAY AND SUNDAY NIGHT...WITH PLENTY OF
RAINFALL EXPECTED TO OCCUR SUNDAY INTO SUNDAY NIGHT. A FRONT WILL
MOVE INTO THE REGION MONDAY AND IS EXPECTED TO STALL NEAR THE
COAST TUESDAY.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
A WEAK UPPER RIDGE WILL CONTINUE BUILDING OVER THE EASTERN CONUS
THROUGH THE OVERNIGHT PERIOD. AT THE SURFACE...VERY DRY HIGH
PRESSURE IS CENTERED OVER THE MID-ATLANTIC COAST. SURFACE
OBSERVATIONS SHOW A STRONG GRADIENT IN DEW POINTS FROM NORTH TO
SOUTH ACROSS THE AREA. EXPECT DRIER AIR TO CONTINUE WORKING SOUTH
OVERNIGHT. WITH DECENT RADIATIONAL COOLING...OVERNIGHT LOWS IN THE
MIDDLE TO UPPER 20S. WINDS WILL BE LIGHT AND OUT OF THE NORTHEAST.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY NIGHT/...
MODELS CONTINUE TO INDICATE UPPER TROUGH TO SHIFT EAST INTO THE
CENTRAL CONUS...WITH UPPER HEIGHT RISES FOR THE SE CONUS. SURFACE
HIGH CENTER TO BEGIN SHIFTING EAST LATE SAT...BUT WEAK SURFACE
RIDGE AXIS CONTINUING TO EXTEND WEST INTO OUR FA. LATEST MODEL
RUNS SLOWER WITH APPROACH OF NEXT SYSTEM AND MOISTURE
RETURN...STILL INDICATING STRONG LOW LEVEL FLOW/MOISTURE FLUX AND
HIGH CONFIDENCE OF POPS...BUT TRENDING A LITTLE LATER SUNDAY INTO
SUNDAY NIGHT. LINGERING WEAK SURFACE RIDGE AXIS OF LOW LEVEL COOL
DRY AIR COULD LEAD TO IN SITU WEDGE DEVELOPING OVER THE FA WITH
THE ONSET OF RAINFALL...WITH SOME QUESTIONS AS TO WHETHER WEAK
WEDGE WILL HOLD OR WHETHER A WARM FRONT CAN TRAVERSE NORTH INTO
PORTIONS OF OUR FA AT SOME POINT SUNDAY/SUN NT. THIS COULD BE A
HIGH SHEAR/LOW INSTABILITY SITUATION FOR PORTIONS OF OUR FA...WITH
SOME THREAT OF SEVERE WEATHER...BUT CONFIDENCE LIMITED AT THIS
TIME DUE TO QUESTIONS REGARDING WEDGE AND WARM FRONT POSITION AND
INDICATIONS OF ONLY WEAK INSTABILITY SOUTH OF THE WARM FRONT.
ALSO...THE MAIN UPPER DYNAMICS AND STRONGEST LOW LEVEL JET ALSO
APPEAR WILL REMAIN TO OUR NORTH. FOR NOW...WILL CONTINUE
CATEGORICAL RAIN CHANCES AND INCLUDE SLIGHT CHANCE THUNDER SUN/SUN
NT.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
UNCERTAINTIES IN THE FORECAST EARLY NEXT WEEK. MODELS KEEP MAIN
UPPER TROUGH AXIS TO OUR WEST THROUGH TUESDAY WITH A SW UPPER FLOW
OVER OUR REGION. BEST ATMOSPHERIC MOISTURE WILL PUSH TOWARDS THE
COAST MONDAY. COLD FRONT WILL MOVE INTO THE REGION MONDAY AND
APPEARS WILL STALL NEAR THE COAST TUESDAY...WITH WAVE OF LOW
PRESSURE POSSIBLY DEVELOPING ALONG THE FRONT. WILL MAINTAIN
CHANCE POPS MON THRU TUE NT...TRENDED HIGHER TO THE EAST. GFS
SUGGESTS UPPER TROUGH TO MOVE INTO THE E CONUS BY
WEDNESDAY/THURSDAY WITH FRONT PUSHING OFFSHORE AND COOL DRIER AIR
MOVING INTO OUR REGION. DRY WEATHER WEDNESDAY THROUGH FRIDAY WITH
UPPER RIDGE BUILDING FROM THE WEST ON FRIDAY. TEMPERATURES ABOVE
NORMAL MONDAY...AND CLOSE TO OR JUST BELOW NORMAL TUESDAY THROUGH
FRIDAY.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
HIGH CONFIDENCE VFR CONDITIONS THROUGH THE 24 HR FORECAST TAF
PERIOD.

HIGH PRESSURE OVER THE CAROLINAS AND MID-ATLANTIC COAST WILL
PROVIDE LIGHT NORTHEAST WINDS OVERNIGHT AND THROUGH THE DAY
SATURDAY WITH MOSTLY CLEAR SKIES THROUGH 18Z. WINDS WILL PICK UP A
BIT AFTER 15Z AND SHIFT MORE TO THE EAST AROUND 5 TO 10 KNOTS.
HIGH CLOUDS WILL INCREASE FROM THE SOUTH LATE IN THE AFTERNOON AND
INTO THE EVENING.

CAN NOT RULE OUT BRIEF PERIODS OF MVFR FOG AT AGS/OGB DUE TO THE
POSSIBILITY OF STEAM FOG COMING OFF THE NEARBY RIVERS. WILL CARRY
A TEMPO GROUP FOR IFR VSBYS AT AGS 07Z-11Z.

EXTENDED AVIATION OUTLOOK...CEILING AND VISIBILITY RESTRICTIONS
ARE LIKELY IN RAIN SHOWERS LATE SATURDAY NIGHT THROUGH MONDAY AS
A LOW PRESSURE SYSTEM AFFECTS THE REGION.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
SC...FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR SCZ030.
GA...NONE.
&&

$$





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