Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 271728
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
128 PM EDT WED AUG 27 2014

.SYNOPSIS...
HIGH PRESSURE WILL WEAKEN ACROSS THE REGION TODAY AND A COLD FRONT
WILL DROP DOWN INTO NORTH CAROLINA FROM THE NORTH ON THURSDAY. THE
FRONT IS EXPECTED TO DISSIPATE AND NOT MOVE ACROSS THE AREA.
MOISTURE AND TEMPERATURES WILL GRADUALLY INCREASE THIS WEEKEND AS A
BERMUDA HIGH REDEVELOPS.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 AM...VSBL SAT PIC SHOWS GENLY SKC...EXCEPT SOME CU OVER
THE SW MOUNTAINS. CURRENT GRIDS ARE IN GOOD SHAPE WITH ONY MINOR
TWEAKS FOR TRENDS.

AS OF 640 AM...KAVL HAS SEEN DENSE FOG SETTLE IN OVER THE PAST ONE
TO TWO HOURS. THE FOG SHOULD LINGER THROUGH SUNRISE...DISSIPATING BY
14Z. I WILL UPDATE THE FORECAST TO ADJUST FOG MENTION. OVERALL...THE
CURRENT FORECAST APPEARS ON TRACK.

AS OF 545 AM...I WILL ISSUE A QUICK UPDATE TO ADJUST THE DENSITY AND
PLACEMENT OF PATCHY FOG ACROSS THE MTNS AND NC FOOTHILLS AND
PIEDMONT. HIGH TEMPERATURES EAST OF I-85 WILL BE INCREASED BY A HALF
DEGREE...BASED ON 6Z GUIDANCE TRENDS. OTHERWISE...THE CURRENT
FORECAST APPEARS IN GREAT SHAPE.

AS OF 320 AM...ANOTHER FAIR WEATHER DAY IN THE OFFING ACROSS THE
WESTERN CAROLINAS AND NORTHEAST GEORGIA. THE SFC PATTERN WILL
FEATURE BROAD HIGH PRESSURE ACROSS THE DEEP SOUTH AS TROPICAL
CYCLONE CRISTOBAL TRACK NORTHEAST OFF THE ATLANTIC COAST. LIGHT
NORTHWEST TO NORTH WINDS WILL LIKELY CONTINUE THROUGH THE DAYLIGHT
HOURS...WITH GENERALLY CALM CONDITIONS SHORTLY AFTER SUNSET THIS
EVENING. BETWEEN SUNRISE AND 21Z...GFS INDICATES THAT H85 TEMPS WILL
WARM FROM 16C TO 20C. THE COMBINATION OF LIGHT DOWNSLOPE
FLOW...MOSTLY SUNNY CONDITIONS...AND MILD LLVL TEMPS SHOULD YIELD
HIGHS CLOSE TO NORMAL THIS AFTERNOON. I WILL FORECAST HIGHS IN THE
LOW TO MID 80S WITHIN THE MTN VALLEYS TO UPPER 80S TO NEAR 90 ACROSS
THE PIEDMONT. FORECAST SOUNDINGS INDICATE DEEP DRY ACROSS THE
REGION...PW VALUES AS LOW AS A HALF INCH...NEARLY 2SD BELOW NORMAL.
THE ENVIRONMENT TODAY WILL SUPPORT ZERO POPS.

TONIGHT...NEAR TERM GUIDANCE INDICATES THAT TROPICAL CYCLONE
CRISTOBAL WILL TRACK NORTH OFF THE MID ATLANTIC COAST. THE
CIRCULATION AROUND THE LOW WILL ASSIST THE SOUTHWARD DRIVE OF A WEAK
BACK DOOR FRONT TONIGHT. THE BOUNDARY IS EXPECTED TO REACH THE
NORTHERN TIER OF THE FORECAST AREA BY SUNRISE THURSDAY...NAM IS A
LITTLE FASTER. THE APPROACH OF THE BOUNDARY SHOULD RESULT IN
INCREASING HIGH CLOUDS FROM THE NORTH LATE TONIGHT. AS A
RESULT...LOW TEMPERATURES ARE FORECAST TO REMAIN A FEW DEGREES
WARMER THAN THIS MORNING/S VALUES.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 330 AM WEDNESDAY...VERY LITTLE CHANGE TO EARLIER THINKING AS
LATEST MODEL RUNS GENERALLY AGREE WITH THE FORECAST. THE COLD FRONT
DROPPING DOWN FROM THE NORTH IS STILL EXPECTED TO STALL VARIOUSLY
ACROSS THE AREA FROM I-40 TO THE VA BORDER ON THURSDAY. THIS COULD
PROVIDE SOME FOCUS FOR SHOWER ACTIVITY OVER THE NRN TIER OF ZONES...
AND THE NAM IS MOST SUPPORTIVE OF THAT. A SLIGHT CHANCE POP WILL BE
EXPANDED JUST A BIT OVER THE NC PIEDMONT BASED ON NEIGHBORING FCSTS.
OTHERWISE...THE MTNS SHOULD SEE SOME ACTIVITY THANKS TO DIFFERENTIAL
HEATING. FRIDAY LOOKS FAIRLY BENIGN AS WELL WITH THE MODELS SHOWING
VERY LITTLE RESPONSE WHILE REBUILDING THE UPPER RIDGE OVER THE
CAROLINAS AND SOUTHEAST COAST. GOING WITH THE IDEA THAT IT IS
DIFFICULT TO SUPPRESS ALL SHOWER ACTIVITY OVER THE MTNS AT THIS TIME
OF YEAR...WILL INCLUDE A SLIGHT CHANCE OVER THE RIDGETOPS. TEMPS
WILL BE VERY CLOSE TO NORMAL THROUGH THE PERIOD.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 330 AM WEDNESDAY...STILL LOOKS LIKE A RETURN TO TYPICAL
SUMMERTIME ACROSS THE REGION FOR THE WEEKEND AND EARLY NEXT WEEK.
THE UPPER RIDGE ALONG THE EAST COAST WILL SUPPORT A BERMUDA HIGH
THAT WILL DO ITS PART BY BRINGING GULF MOISTURE BACK INTO THE REGION
STARTING ON SATURDAY. THAT SHOULD FUEL MAINLY DIURNAL SHOWERS AND
STORMS THAT WILL BE MOST NUMEROUS ON SUNDAY WHEN A JET STREAK
PASSING TO THE NW BRINGS A SHOT OF UPPER DIVERGENCE ACROSS THE
REGION AND A SHORT WAVE LIFTING TO THE NE WILL PASS OVER THE TN
VALLEY/SRN APPALACHIANS DURING PEAK HEATING. THE PRECIP PROBABILITY
WAS LIMITED TO THE CHANCE RANGE FOR NOW...UNTIL THERE IS MORE RUN TO
RUN CONSISTENCY. PRECIP COVERAGE WILL DROP OFF MONDAY AND TUESDAY
WITH LESS UPPER SUPPORT. TEMPS WILL BE ABOVE NORMAL.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AT KCLT AND AIRFIELDS EAST OF THE MTNS...EXPECT CONTINUED VFR
CONDITIONS FOR VSBY AND SKY THROUGH THE PERIOD. THE SFC PATTERN WILL
SUPPORT A GENERALLY N-NW WIND ACROSS THE TERMINALS. SPEEDS WILL REMAIN
5-10 KTS DURING THE DAYLIGHT HOURS...BECOMING CALM DURING THE NIGHT.

AT KAVL...CLEAR AND CALM CONDITIONS WILL PROMOTE VALLEY FOG
FORMATION AGAIN TONIGHT. EXPECT LIFR CONDITIONS IN FOG IN THE
10Z-14Z TIMEFRAME. OTHERWISE VFR CONDITIONS WILL PREVAIL.

OUTLOOK...A BACKDOOR COLD FRONT IS EXPECTED TO TRIGGER SCT MOUNTAIN
THUNDERSTORMS THUSDAY AFTERNOON AND EVENING. THE AIRMASS WILL
MOISTEN OVER THE WEEKEND TO SUPPORT ISOLD TO SCT DIURNAL
THUNDERSTORMS...ESPECIALLY ACROSS THE MTNS. MORNING LOW CLOUDS AND
FOG WILL REMAIN POSSIBLE DURING THE EARLY MORNING...ESPECIALLY IN
THE MTN VALLEYS.

CONFIDENCE TABLE...

            17-23Z        23-05Z        05-11Z        11-17Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       HIGH 100%     HIGH 100%     HIGH  85%     HIGH  81%
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...PM
NEAR TERM...LG
SHORT TERM...PM
LONG TERM...PM
AVIATION...LG






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