Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 010013
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
813 PM EDT SUN AUG 31 2014

.SYNOPSIS...
A BERMUDA HIGH WILL REMAIN IN PLACE THROUGH EARLY IN THE
WEEK... RESULTING IN TYPICAL SUMMERTIME HEAT AND ISOLATED TO
SCATTERED AFTERNOON THUNDERSTORMS EACH DAY.

&&

.NEAR TERM /THROUGH MONDAY/...
AS OF 755 PM EDT...A SERIES OF WEAK SHORTWAVES CONTINUE TO LIFT NE
ACROSS EXTREME NW NC THIS EVENING. THIS UPPER ENERGY WILL PULL AWAY
TO THE NE AFTER MIDNIGHT WITH ANY RESIDUAL VORT LOBES PASSING ALONG
THE SPINE OF THE SRN APPALACHIANS BEING QUITE WEAK OVERNIGHT. IN
ADDITION...THE LOSS OF DAYTIME HEATING SHOULD PERMIT LINGERING
PIEDMONT CONVECTION TO DIMINISH ONCE THE LINGERING OUTFLOWS
DISSIPATE. FOG AND LOW CLOUDS WILL BE AN ISSUE OVERNIGHT MAINLY IN
THE MOUNTAIN VALLEYS WHERE CROSSOVER TEMPS WILL BE REACHED AND ALSO
ALONG AND N OF INTERSTATE 40 WHERE HEAVIER RAIN FELL TODAY. MINS
HAVE BEEN ADJUSTED UP A DEGREE IN MOST AREAS TONIGHT.

OTHERWISE...BERMUDA HIGH WILL REMAIN STRONG THROUGH MONDAY. A BIT
MORE MIXING IS EXPECTED TOMORROW...WITH RH VALUES A LITTLE MORE
TOLERABLE. EXPECT HIGHS A LITTLE ABOVE NORMAL. ISOLD TO SCT DIURNAL
CONVECTION WILL FAVOR THE HIGH TERRAIN MON AFTN.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
AS OF 215 PM SATURDAY...TYPICAL LATE SUMMER WEATHER IS EXPECTED
THROUGH THE SHORT TERM...AS SUBTROPICAL/BERMUDA HIGH PRESSURE
GENERALLY MAINTAINS ITS HOLD ACROSS THE SOUTHEAST. A SHORT WAVE
TROUGH PASSING NORTH OF OUR REGION LATE TUE. ASSOCIATED COLD FRONT
WILL APPROACH THE SOUTHERN APPALACHIANS FROM THE TENN VALLEY TUE
EVENING... POSSIBLY ENHANCING CONVECTIVE CHANCES ACROSS THE NC MTNS
DURING THIS TIME. HOWEVER...WITH THE PRIMARY SYNOPTIC SCALE FORCING
PASSING BY TO OUR NORTH...WEAK SHEAR...AND WEAKENING INSTABILITY
ASSOCIATED WITH THE NOCTURNAL COOLING CYCLE...IT/S NOT CLEAR HOW
LONG INTO TUE NIGHT CONVECTION WILL CONTINUE BEFORE DISSIPATING.
CHANCE POPS HAVE GENERALLY BEE LIMITED TO THE EVENING HOURS.

THE FRONT IS EXPECTED TO INTRODUCE A SLIGHTLY COOLER/SLIGHT DRIER
AIR MASS TO THE AREA...WITH TEMPS EXPECTED TO TOP OUT CLOSER TO
CLIMO FOR WED AFTERNOON. IT DOES NOT APPEAR THAT ANY DRYING WILL BE
SUBSTANTIAL ENOUGH TO PRECLUDE AFTERNOON DESTABILIZATION AND DIURNAL
CONVECTIVE DEVELOPMENT. NEAR-CLIMO POPS (LOW CHANCE MTNS/SLIGHT
CHANCE EAST) WILL BE ADVERTISED WED AFTERNOON.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 230 PM EDT SUNDAY...LATEST GLOBAL MODELS HAVE TRENDED WEAKER
UPPER RIDGING ACROSS THE SOUTHERN CONUS...LEADING TO INCREASING
CHANCES FOR CONVECTION THROUGHOUT THE MEDIUM RANGE PERIOD. WED NIGHT
THRU FRI...MODELS STILL DEPICT UPPER RIDGING AMPLIFYING ACROSS THE
REGION THRU THU...THEN WEAKENS BY FRI IN RESPONSE TO A NORTHERN
UPPER TROUGH TRAVERSING THE UPPER MIDWEST. A FRONTAL BOUNDARY JUST
TO OUR SOUTH WILL BE WASHED OUT BY THURSDAY AS A BERMUDA HIGH
RE-BUILDS ACROSS THE SOUTHEAST AND REMAIN IN PLACE THRU FRI. DESPITE
THE UPPER RIDGING ALOFT...ATLANTIC MOISTURE INFLUX AND MODERATE
DIURNAL BUOYANCY (1500-2500J/KG SBCAPE) WILL BE SUPPORTIVE OF
SCATTERED CONVECTION. HENCE...HAVE UPDATED POPS TO INCREASE TO
AROUND 40-50 RANGE. SAT AND SUNDAY...THE UPPER RIDGE FLATTENS OUT
OVER THE SOUTHEAST AS THE UPPER TROUGH MOVES ACROSS THE GREAT LAKES
REGION SAT AND INTO THE OHIO VALLEY BY SUN. THIS WILL ALLOW COOLER
SURFACE HIGH TO SLIDE SOUTH...PUSHING A BACK DOOR COLD FRONT THROUGH
THE FORECAST AREA BY SAT NIGHT/EARLY SUN. WITH GOOD LLVL
CONVERGENCE...UPPER DPVA...MOIST PROFILE AND MODERATE
INSTABILITY...WE SHOULD SEE RATHER ACTIVE WEATHER PATTERN WITH HEAVY
RAINFALL BEING THE PRIMARY THREAT ATT. TEMPS WILL BE AROUND 2-3
DEGREES ABOVE NORMAL THURSDAY AND NEAR NORMAL FRI INTO SUN.

&&

.AVIATION /00Z MONDAY THROUGH FRIDAY/...
AT KCLT...ANY RESIDUAL LATE EVENING CONVECTION WILL PASS WELL N OF
THE AIRFIELD WITH ANY DEPARTING UPPER SHORTWAVES. EXPECT MAINLY FEW
CU UNDER A WEAK CAP OVERNIGHT WITH SCT HIGH CLOUDS. LOW LEVELS WILL
BE MOIST...BUT MOS AND MODEL CONSENSUS CURRENTLY POINT TO NOTHING
WORSE THAN MVFR FOG AROUND DAYBREAK. EXPECT MAINLY LIGHT SW
FLOW...PICKING UP WITH MIXING AND TURNING MORE SW TO WSW THROUGH
MONDAY. CONVECTIVE CHANCES LOOK QUITE LOW ON MONDAY GIVEN THE LACK
OF TRIGGERS.

ELSEWHERE...ADDITIONAL WEAK SHORTWAVES WILL RIDE NE ALONG THE SPINE
OF THE APPALACHIANS OVERNIGHT...BUT WITH ANY WEAK CONVECTION
REMAINING GENERALLY W OF KAVL. LOW CLOUDS AND FOG WILL BE THE
PRIMARY CONCERN FROM KAVL TO KHKY...WHERE CROSSOVER TEMPS WILL BE
REACHED AND GIVEN THE RECENT PERFORMANCE. WILL GO AHEAD AND FEATURE
IFR FOG AT KAVL BUT HOLD ON TO MVFR AT KHKY GIVEN THAT THE AFTN
PRECIPITATION MISSED THE AIRFIELD TO THE N AND MOST CONSENSUS LEANS
STRONGLY TO MVFR AT PRESENT. BRIEF MVFR FOG WILL BE POSSIBLE AT THE
UPSTATE SITES TOWARD DAYBREAK AS WELL. EXPECT SW TO WSW WINDS TO
INCREASE AGAIN WITH MIXING MON AT THE FOOTHILL SITES...WHILE NW
WINDS AT KAVL EARLY WILL TURN TO SRLY THROUGH MON AFTN. EXPECT
MAINLY SCT CUMULUS WITH HEATING...BKN AT TIMES FROM KAVL TO
KHKY...WITH CONVECTIVE CHANCES TOO LOW TO MENTION AT THIS POINT FOR
MON AFTN.

OUTLOOK...GENERALLY VFR CONDITIONS ARE EXPECTED THROUGH MOST OF THE
WEEK...BUT RESTRICTIONS ARE POSSIBLE EARLY EACH MORNING DUE TO LOW
CLOUDS AND FOG...PRIMARILY IN THE MOUNTAIN VALLEYS. DIURNALLY DRIVEN
SHRA/TSRA ARE EXPECTED EACH AFTERNOON WITH THE MOST COVERAGE OVER
THE MOUNTAINS.

CONFIDENCE TABLE...

            00-06Z        06-12Z        12-18Z        18-24Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       HIGH 100%     MED   79%     HIGH  86%     HIGH 100%
KHKY       HIGH 100%     HIGH  95%     HIGH 100%     HIGH 100%
KGMU       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAND       HIGH 100%     HIGH  87%     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...JOH
NEAR TERM...HG
SHORT TERM...JDL
LONG TERM...JOH
AVIATION...HG





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