Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 290255
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
955 PM EST FRI NOV 28 2014

.SYNOPSIS...
CANADIAN HIGH PRESSURE WILL REMAIN ACROSS THE REGION THROUGH MONDAY
AND GRADUALLY WARM EACH DAY. A COLD FRONT WILL THEN PUSH ACROSS THE
FORECAST AREA FROM THE NORTH EARLY TUESDAY.

&&

.NEAR TERM /THROUGH SATURDAY/...
AS OF 930 PM...A QUIET EVENING ACROSS NORTHEAST GEORGIA AND THE WRN
CAROLINAS. TEMPS WERE DROPPING OFF QUICKER THAN FCST IN SOME
LOCATIONS...SO THE TEMP TREND WILL BE ADJUSTED TO ACCOUNT FOR THIS.
OTHERWISE...THE FCST WAS IN DECENT SHAPE.

REMAINDER OF PREVIOUS DISCUSSION...

THE CIRRUS SHUD INCREASE OVERNIGHT AS UPPER LEVEL MOISTURE INCREASES
AND A WEAK SHORT WAVE AND UPPER JET MAX MOVES THRU IN THE DEVELOPING
ZONAL FLOW. AT THE SFC...HIGH PRESSURE MOVES SLOWLY OFF SHORE THRU
THE PERIOD...BRINGING CALM OR LIGHT AND VARIABLE WINDS TONIGHT THEN
INCREASING SWLY WINDS SAT. LOWS TONIGHT SHUD BE 5 TO 10 DEGREES
BELOW NORMAL...TEMPERED BY THE INCREASE IN CIRRUS AND RISING LOW
LEVEL THICKNESSES. HIGHS WILL BE NEAR NORMAL ACROSS THE MTNS SAT AND
AROUND 5 DEGREES BELOW NORMAL ELSEWHERE AS THICKNESSES CONTINUE TO
RISE...FASTER ACROSS THE MTNS THAN THE PIEDMONT.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
AS OF 200 PM EST FRIDAY...THE SHORT TERM PERIOD INITIALIZES SATURDAY
EVENING AMIDST DEAMPLIFIED UPPER FLOW WITH SURFACE HIGH PRESSURE
PREVAILING ACROSS THE SOUTHEAST.  FURTHERMORE...SURFACE LOW PRESSURE
EJECTING OVER THE GREAT LAKES WILL MAKE WAY FOR CANADIAN HIGH
PRESSURE DIVING THROUGH THE NORTHERN ROCKIES.  WARM ADVECTION AHEAD
OF WEAK COLD FRONTAL BOUNDARY ASSOCIATED WITH DEPARTING NORTHERN LOW
WILL CONTINUE ACROSS THE DEEP SOUTH THROUGH THE REMAINDER OF THE
PERIOD.  MOIST UPGLIDE REGIME ACROSS THE MIDSOUTH WILL PREVAIL
THROUGH SUNDAY AND INTO MONDAY WITH THE PRIMARY MOISTURE AXIS SLOWLY
ADVECTING EASTWARD WITH TIME.

BY MONDAY MORNING GUIDANCE FAVORS COLD ADVECTION RAMPING UP ACROSS
THE MIDWEST INTO THE OHIO VALLEY ASSOCIATED WITH A REINFORCING COLD
FRONT. ISENTROPIC ASCENT REGION WILL SHIFT EAST AHEAD OF THE FRONT
LEADING TO IMPROVED UPGLIDE ACROSS THE SOUTHWEST NC AND NORTHEAST GA
MOUNTAINS BY EARLY MONDAY MORNING.  MODELS FAVOR INCREASING COVERAGE
ALONG THE MOUNTAINS THROUGH THE DAY AS THE COLD FRONT APPROACHES
FROM THE NORTHWEST EVENTUALLY SLIDING THROUGH THE CUMBERLAND PLATEAU
BY PERIODS END.  THUS...THE FORECAST WILL REMAIN DRY THROUGH SUNDAY
WITH SLIGHT CHANCE POPS BEING INTRODUCED ACROSS THE SOUTHWEST NC AND
NORTHEAST GA MOUNTAINS MONDAY MORNING.   POPS SPREAD OUT ACROSS THE
ENTIRETY OF THE NC/GA MOUNTAINS THROUGH THE DAY WITH CHANCE LEVEL
POPS FEATURED BY MONDAY EVENING.  TEMPERATURES WILL CONTINUE TO
MODERATE THROUGH THE PERIOD WITH HIGHS TOPPING OUT NEARLY 5-10
DEGREES ABOVE NORMAL FOR MOST LOCATIONS ON MONDAY.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 230 PM EST FRIDAY...LATEST GLOBAL MODELS CONTINUE TO INDICATE
THAT A BACK DOOR COLD FRONT WILL SLIP THROUGH THE FORECAST AREA
THROUGH MON NIGHT WITH A CAD SETTING UP BY TUE AS 1043+MB CANADIAN
HIGH PRESSURE OVER THE OHIO VALLEY SLIDES INTO NEW ENGLAND. BOTH THE
12Z GFS AND ECMWF TRENDED A BIT WETTER...ESPECIALLY OVER THE NC
ZONES ON TUE...IN LIGHT OF UPPER WAVE EMBEDDED WITH A SERIES OF
STRONGER UPPER DISTURBANCES MOVING THROUGH OVER MOIST ISENTROPIC
UPGLIDE REGIME. THEREFORE...HAVE RAISED POPS INTO THE SOLID CHANCE
RANGE OVER THE NORTHERN HALF OF THE CWA ON TUE. THERMAL PROFILE PER
12Z GFS IS SUPPORTIVE OF FREEZING RAIN MON NIGHT THROUGH TUE
MORNING...MAINLY AREAS NORTH OF I-40. HOWEVER...THE NEW 12Z ECMWF
KEEPS COLDER AIRMASS WELL NORTH OF THE CWA...SUGGESTING ALL LIQUID
PRECIP. THEREFORE...HAVE NOT MENTIONED ANY FROZEN PRECIP AT THIS
TIME. CONDITIONS SHOULD DRY OUT BY LATE WED...AS WEAK UPPER RIDGING
BUILD IN FROM THE WEST AND THE CAD ERODES IN RESPONSE TO AN
APPROACHING COLD FRONT FROM THE NW. THE GFS SUGGESTS THE FROPA WILL
OCCUR ON FRI WHILE THE ECMWF IS AROUND 24HRS LATE...OCCURRING ON
SAT. GIVEN THE UNCERTAINTY...HAVE MENTIONED SLIGHT CHANCE POPS OVER
THE PEDIMENT WITH LOW END CHANCE POPS OVER THE MTNS ZONES ON
FRI...RAMPING DOWN TOWARD FRI NIGHT. TEMPS ON TUE SHOULD REMAIN
AROUND 10-15 DEGREES BELOW NORMAL...WITH NEAR NORMAL WED THRU FRI.

&&

.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT AND ELSEWHERE...VFR THROUGH THE PERIOD. WITH THE CENTER OF
HIGH PRESSURE E OF THE AREA...ANY REMAINING LIGHT WIND WILL BE FROM
A SW DIRECTION OUTSIDE THE MTNS...AND CHANNELED FROM THE NW AT KAVL.
JET STREAK CIRRUS WILL KEEP SOME SCT HIGH CLOUDINESS OVERHEAD
OVERNIGHT. WINDS WILL RETURN FROM THE SW BY LATE MORNING SATURDAY
AND JUST A BIT STRONGER...BUT STILL UNDER 10 KT...WITH THE HIGH
CENTER FARTHER OFFSHORE.

OUTLOOK...LOW CLOUDS ARE POSSIBLE SUNDAY MORNING IN THE MOIST SLY
FLOW AHEAD OF A COLD FRONT. THE FRONT WILL SLOWLY SLIP SOUTH ACROSS
THE SOUTHERN APPALACHIANS ON MONDAY. ON TUESDAY...A STRONG RIDGE OF
HIGH PRESSURE WILL BUILD ACROSS THE REGION FROM THE NORTH WITH
INCREASING LOW LEVEL MOISTURE...LIKELY RESULTING IN WIDESPREAD
CEILING RESTRICTIONS THROUGH MID WEEK AS A COLD AIR DAMMING
WEDGE DEVELOPS.

CONFIDENCE TABLE...

            03-09Z        09-15Z        15-21Z        21-00Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KHKY       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGMU       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAND       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.

&&

$$
SYNOPSIS...SBK
NEAR TERM...PM/RWH
SHORT TERM...CDG
LONG TERM...JOH
AVIATION...PM


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