681
FXUS62 KGSP 091151
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
651 AM EST MON NOV 9 2009
SYNOPSIS
A RIDGE OF HIGH PRESSURE WILL REMAIN OVER THE AREA THROUGH TODAY.
THEN ABUNDANT MOISTURE ASSOCIATED WITH IDA IS EXPECTED TO MOVE OVER
THE REGION AHEAD OF A COLD FRONT TUESDAY. THE FRONT WILL CROSS THE
AREA LATE TUESDAY INTO EARLY WEDNESDAY. HIGH PRESSURE WILL THEN
RETURN FOR THE LATTER PART OF THE WEEK.
NEAR TERM /THROUGH TONIGHT/
ONE MORE DRY/PLEASANT DAY IS IN STORE FOR THE WESTERN CAROLINAS/
NORTH GEORGIA BEFORE THE BOTTOM FALLS OUT. THICKNESS VALUES TODAY
ARE PROGGED TO BE SIMILAR TO SUNDAY. HOWEVER...A COOLING EASTERLY
FLOW AND INCREASING HIGH CLOUDS SHOULD PUT A HALT TO YESTERDAY/S
NEAR-RECORD READINGS.
CONDITIONS SHOULD DETERIORATE RATHER QUICKLY AFTER MIDNIGHT
TONIGHT...AS TROPICAL MOISTURE PLUME/STRONG ISENTROPIC LIFT
OVERSPREADS THE REGION IN ADVANCE OF HURRICANE IDA. THE GFS IS THE
MODEL THAT MOST CLOSELY REPRESENTS OFFICIAL NHC TRACK GUIDANCE...
ALTHOUGH THE MODEL IS A BIT FASTER THAN THE OFFICIAL TRACK GUIDANCE.
FOR OUR FORECAST...THE GFS WAS BLENDED WITH HPC GUIDANCE AS WELL AS
SLIGHTLY SLOWER/FURTHER WEST MODELS SUCH AS THE ECMWF AND CANADIAN
GEM IN ORDER TO SLOW THE ONSET OF PRECIP SOMEWHAT. NEVERTHELESS...
WE WILL ADVERTISE CATEGORICAL POPS NUDGING THEIR WAY INTO OUR
NORTHEAST GEORGIA COUNTIES BY 12Z TUESDAY.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/
AS OF 250 AM MONDAY...MODELS CONTINUE TO STRUGGLE WITH VARIOUS
SOLUTIONS AS HURRICANE IDA MAKES LANDFALL ALONG THE GULF COAST TUE
MRNG. LATEST NHC TRACK HAS IT MAKING LANDFALL OVER THE W PANHANDLE
OF FL TUE MRNG...THEN MOVG E ACROSS FAR S AL AND ALONG THE GA-FL
BORDER TOWARD THE ATLANTIC COAST. THIS IS CLOSER TO THE ECMWF AND
GEM SOLUTIONS WITH THE GFS BEING FARTHER N AND THE NAM FARTHER S. SO
USING A BLEND CLOSER TO THE ECMWF...EXPECT BEST MOISTURE...
ISENTROPIC LIFT AND UPSLOPE FLOW DURG DAY TUE. WITH THE UPPER TROF
MOVG IN FROM THE W BROUGHT CATEGORICAL POPS INTO THE W ZONES TUE
MRNG...SPREADING ACROSS THE CWA TUE AFTN WITH LIKELY POPS CONTINUING
TUE NIGHT BEFORE TAPERING OFF FROM THE W WED MRNG AS UPSLOPE WEAKENS
AND MOISTURE TRACKS E. FOLLOWED HPC QPF TUE THRU TUE NIGHT WHICH
SHOWS OVER 4 INCHES OF RAIN ALONG THE BEST UPSLOPE AREAS OF THE W
BLUE RIDGE ESCARPMENT...INCLUDING THE S NC MTNS AND THE FOOTHILLS OF
UPSTATE SC AND NE GA. WILL GO WITH A FLASH FLOOD WATCH FOR THAT AREA
TUE-WED MRNG. WITH LOW LEVEL FLOW WRAPPING AROUND APPROACHING LOW
TUE...SFC WINDS WILL BE NELY AND AS THKNS DECREASES WITH THE
APPROACHING UPPER TROF...TEMPS WILL BE BELOW AVG. EXPECT SOME
SUNSHINE IN THE W LATER WED AND TEMPS WILL RECOVERY A COUPLE DEG BUT
STAY COOLER IN THE E. MRNG LOWS WILL BE ABOVE AVG WED...COOLING TO
BELOW AVG THU MRNG AS COOLER AIR GETS PULLED IN BEHIND DEPARTING LOW.
LONG TERM /THURSDAY THROUGH SUNDAY/
AS OF 250 AM MONDAY...EXPECT UPPER TROF AND SFC REMNANTS OF IDA TO
CONT TRACKING OFF TO THE E THU WITH COOL...DRY AIR OVER THE AREA AS
SFC RIDGE BUILDS IN FROM THE N. TEMPS SHOULD BE BELOW AVG THU...THEN
RECOVER FRI THRU THE WEEKEND AS UPPER RIDGE BUILDS OVER THE AREA...
THE SFC HIGH MOVES OFFSHORE AND N FLOW WEAKENS. S RETURN FLOW
AROUND THE HIGH WILL BRING INCRSNG MOISTURE INTO THE S
APPALACHIANS LATER IN THE WEEKEND SO BACKED OFF POPS SAT
AFTN...WITH JUST SLIGHT CHC SUN OVER THE MTNS AND ADJACENT
FOOTHILLS.
AVIATION /12Z MONDAY THROUGH FRIDAY/
AT KCLT AND ELSEWHERE...WINDS WILL GRADUALLY INCREASE OUT OF THE
NORTHEAST LATER THIS MORNING...BUT SHOULD REMAIN AROUND 5 KT OR SO
THROUGH MOST OF THE PERIOD. OTHERWISE...THE NEXT 18 HOURS OR SO WILL
SEE LITTLE MORE THAN BKN-OVC CIRRUS. BY THE END OF THE FORECAST
PERIOD...THE INITIAL SURGE OF LOW LEVEL MOISTURE ASSOCIATED WITH THE
CIRCULATION AROUND HURRICANE IDA WILL LIKELY RESULT IN STRATOCU
DEVELOPMENT. AT THIS POINT...I DO NOT HAVE SUFFICIENT CONFIDENCE TO
FORECAST ANY CIGS BELOW MVFR.
OUTLOOK...A COLD FRONT WILL APPROACH FROM THE WEST TUESDAY...AS THE
REMNANTS OF IDA MOVE SLOWLY ALONG THE GULF COAST. ABUNDANT TROPICAL
MOISTURE WILL RESULT IN PERIODS OF MODERATE-HEAVY RAIN ALONG WITH
CIG/VSBY RESTRICTIONS ACROSS THE AREA FROM LATE TUE MORNING INTO
EARLY WEDNESDAY.
GSP WATCHES/WARNINGS/ADVISORIES
GA...FLASH FLOOD WATCH FROM TUESDAY MORNING THROUGH WEDNESDAY
MORNING FOR GAZ010-017-018-026-028.
NC...FLASH FLOOD WATCH FROM TUESDAY MORNING THROUGH WEDNESDAY
MORNING FOR NCZ062>065-509.
SC...FLASH FLOOD WATCH FROM TUESDAY MORNING THROUGH WEDNESDAY
MORNING FOR SCZ001>005-010.
SYNOPSIS...RB
NEAR TERM...JDL
SHORT TERM...RB
LONG TERM...RB
AVIATION...JDL
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