Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 020841
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
441 AM EDT SAT AUG 2 2014

.SYNOPSIS...
HIGH PRESSURE WILL REMAIN WEDGED OVER THE CAROLINAS TODAY AS AN
UPPER TROUGH STAYS CENTERED TO OUR WEST. TO THE EAST...A FRONT WILL
REMAIN NEARLY STATIONARY ALONG THE COAST ALLOWING DEEP ATLANTIC
MOISTURE TO CONTINUE TO SPREAD OVER THE AREA. CONDITIONS ARE
EXPECTED TO RETURN TO A MORE TYPICAL LATE SUMMER PATTERN BY THE
MIDDLE OF NEXT WEEK AS THE BERMUDA HIGH STRENGTHENS TO OUR EAST.

&&

.NEAR TERM /THROUGH TONIGHT/...
430 AM EDT UPDATE...MADE SOME DOWNWARD TWEAKS TO MAX TEMPS AND
INCORPORATED THE LOWER CONSRAW GUIDANCE. IT LOOKS MORE AND MORE LIKE
CLOUDS WILL BE SLOW TO LIFT AND BREAK UP TODAY WHILE A PERSISTENT
WEDGE FLOW REMAINS IN PLACE. MAX TEMPS NOW FEATURE U70S NON/MTNS AND
M70S MTN VALLEYS.

AS OF 215 AM...A PERSISTENT UPPER LEVEL TROF PATTERN WILL CONTINUE
TO DOMINATE THROUGH THE NEAR TERM...WITH A WEAK HYBRID WEDGE
REMAINING ACROSS THE LOW LEVELS. THE LATEST 12K NAM LOOKS TOO FAR
WEST AND OVERDONE WITH THE AMOUNT OF CONVECTION AND INSTABILITY THIS
AFTERNOON. THE SFC WEDGE SHOULD WEAKEN...BUT WILL SIDE MORE WITH THE
ERN GFS AND TO SOME DEGREE THE SREF WITH THE PLACEMENT OF DEEP
CONVECTION ALONG WEAK WEDGE BNDRY. WILL STILL COUNT OF GOOD UPSLOPE
FLOW PRODUCING THE BEST PRECIP CHANCES ACROSS THE NC ESCARPMENT AND
BLUE RIDGE THIS AFTERNOON. CLOUDS SHOULD BE SLOW TO BREAK UP THIS
AFTERNOON OR THEY COULD PERSIST WIDESPREAD AS POCKETS OF S/W ENERGY
ENHANCE OVERALL LIFT. EASTERLY MOISTURE FLUX COULD WANE THIS
AFTERNOON WITH DEEP COASTAL CONVECTION LIKELY INCREASING ISOLATION
ACROSS THE EAST. NONETHELESS...SFC BASED INSTABILITY SHOULD BE LOW
END PER MODEL SOUNDINGS AS MAX TEMPS ARE STILL HELD ABOUT 6-8
DEGREES BELOW NORMAL. THUNDER CHANCES HAVE THUS BEEN REDUCED INTO
THE LOWER CHANCE RANGE MOST LOCALES THIS AFTERNOON. STORMS THAT DO
DEVELOP THIS AFTERNOON SHOULD REMAIN GENERAL WITH NO GREAT HEAVY
PRECIP SIGNATURES NOTED AND CTG LIGHTNING SHOULD BE THE MAIN THREAT.
OVERNIGHT...NUMEROUS CLOUDS WILL PERSIST BUT DRYING WILL COMMENCE
FROM THE TOP DOWN ACROSS THE WRN ZONES AFT 03Z. MIN TEMPS WILL BE
HELD A COUPLE DEGREES BELOW NORMAL IN CONTINUED WEAK...BUT NE/LY
FLOW.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 230 AM EDT SATURDAY...THE SHORT TERM FCST PICKS UP AT 12Z ON
SUNDAY WITH THE POSITIVELY TILTED UPPER TROUGH AXIS JUST TO OUR
WEST. OVER THE NEXT COUPLE OF DAYS...THE UPPER TROF IS EXPECTED TO
REMAIN LARGELY IN PLACE OVER THE EASTERN CONUS AND WILL LIKELY
DEAMPLIFY A BIT AS THE NORTHERN STREAM LIFTS AND THE PATTERN BECOMES
MORE ZONAL.

ON SUNDAY...HIGH PRESSURE FROM THE NW WILL PUSH A COLD FRONT OVER
THE WESTERN CAROLINAS AND ALLOW DRIER AIR TO SPREAD OVER THE CWFA.
AS THE BNDY STALLS OVER THE REGION...PRETTY MUCH ALL OF THE MODELS
DEPICT A FAIRLY SHARP GRADIENT OF DEEPER MOISTURE JUST TO OUR SE
WITH THE HIGHEST VALUES ALONG THE COAST. THUS...I KEEP ANY SOLID
CHANCE POPS RELEGATED TO THE SE ZONES WITH A SLIGHT CHANCE
ELSEWHERE. SOME DECENT INSTABILITY EXISTS OVER PORTIONS OF THE
UPSTATE AND PIEDMONT...THUS SCATTERED TS...SOME WITH STRONG UPDRAFTS
ARE POSSIBLE. TEMPS WILL CLIMB BACK INTO THE LOW TO MID 80S FOR
LOWER ELEVATIONS.

ON MONDAY...NO MAJOR CHANGES IN THE SFC PATTERN ARE EXPECTED WITH
THE STALLED FRONTAL BNDY LINGERING JUST TO OUR SE AND TROPICAL STORM
BERTHA APPROACHING THE SE COAST BY EARLY TUES. AN INCREASE IN DEEP
LYR MOISTURE ASSOCIATED WITH BERTHA IS EXPECTED TO REMAIN TO OUR
SOUTH AND EAST AND THE SYSTEM SHOULD HAVE LITTLE IMPACT ON OUR
SENSIBLE WX. OTHERWISE...I EXPECT MOSTLY DIURNAL SLIGHT CHANCE TO
SOLID CHANCE SHOWERS AND TS WITH TEMPS A FEW DEGREES WARMER THAN THE
PREVIOUS DAY.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 240 AM SATURDAY...THE MEDIUM RANGE PICKS UP AT 12Z ON TUESDAY
WITH THE PERSISTENT EASTERN CONUS UPPER TROF STILL LINGERING JUST TO
OUR NORTH. THE LATEST MODEL GUIDANCE IS NOW SUGGESTING THAT THE TROF
WILL LIKELY FLATTEN OUT AS WE MOVE TOWARDS THE END OF THE WORK WEEK
AND THE PATTERN DEAMPLIFIES.

AT THE SFC...WEAK HIGH PRESSURE CENTERED OVER THE OHIO RIVER VALLEY
WILL KEEP DRIER AIR IN PLACE OVER THE CWFA FOR TUES AND WED. BEYOND
THAT...THE LONG RANGE MODELS DIVERGE WRT THE SFC PATTERN EVOLUTION.
THE LATEST 00Z GFS BRINGS ANOTHER ROUND OF DRY AND COOL CANADIAN
HIGH PRESSURE DOWN FROM THE NORTH ON THURS AND THEN SLIDES THE HIGH
OFF THE ATLANTIC SEABOARD ON FRI. ON THE OTHER HAND...THE 12Z ECMWF
IS NOT AS PROGRESSIVE WITH THE HIGH AND DEVELOPS AN ELONGATED ZONE
OF LOW LVL CONVERGENCE SOUTH OF THE GREAT LAKES AND MOVES THIS
CONVERGENCE ZONE SOUTHWARD AND OVER THE FCST AREA ON THURS AND FRI.
THE CANADIAN SOLUTION IS MORE SIMILAR TO THE ECMWF...YET IT KEEPS
THE AFOREMENTIONED CONVERGENCE FARTHER NORTH ON DAYS 6 AND 7. FOR THE
TIME BEING...I WILL CONTINUE TO PLACE MORE FAITH WITH A ECMWF/CMC
TYPE SOLUTION AND NOT DRY THINGS OUT AS MUCH AS THE GFS. THIS
RESULTS IN DIURNALLY DRIVEN SLIGHT TO SOLID CHANCES FOR SHOWERS AND
TS EACH DAY/EVENING WITH THE BEST CHANCES ON FRI AND SAT. TEMPS ARE
EXPECTED TO WARM BACK UP TO NEAR CLIMO FOR EARLY AUGUST.

&&

.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...MOIST UPSLOPE FLOW OVER A SHALLOW WEDGE WILL CONTINUE IFR
STCU OVERNIGHT WITH POSSIBLE TEMPO DROP TO LIFR THROUGH DAYBREAK. A
SLOW RISE IN CIGS TO MVFR THROUGH 17Z AS SFC HEATING WILL BE
LIMITED. VFR CIGS PROBABLE AFT 19Z AND TSTMS WILL BE QUESTIONABLE AS
AMOUNT OF AVAILABLE SFC INSTABILITY IS UNCLEAR...BUT FOR NOW WILL
COUNT ON TRAVERSING ULVL VORT ENERGY TO SUPPORT A PROB30 MENTION 19Z
THROUGH 01Z IN DIFF HEATING.

ELSEWHERE...IFR CONDS WITH POSSIBLY LIFR CIGS THROUGH THE OVERNIGHT
LINGERING INTO MID MORNING AT ALL SITES...EXCEPT FOR KAVL AND KAND
WHERE MVFR WILL TEMPO. WEDGE IS HOLDING STRONG AND LOCKED IN LOW
WITH AREAS OF DZ TRAVERSING THE AREA UNDER THE RADAR...SO THE BL
WILL BE SLOW TO WARM WITH CIGS REACHING MVFR BY ROUGHLY 14Z THEN VFR
ARND 19Z. DEEP CONVECTION IS QUESTIONABLE THIS AFTERNOON...BUT ENUF
UPPER FORCING COULD PRODUCE SCT COVERAGE...SO A VCTS IS INCLUDED ALL
SITES DURING PEAK HEATING.

OUTLOOK...UNSETTLED WEATHER WITH ENHANCED PRECIPITATION CHANCES
ALONG WITH MORNING FOG/STRATUS ARE EXPECTED THROUGH THE WEEKEND.
TEMPERATURES WILL BEGIN TO MODERATE EARLY NEXT WEEK AS A MORE
SUMMERLIKE PATTERN GRADUALLY TAKES HOLD AGAIN...BUT PERIODIC
RESTRICTIONS FROM CLOUDS AND PRECIP ARE STILL LIKELY AT THAT TIME.

CONFIDENCE TABLE...

            08-14Z        14-20Z        20-02Z        02-08Z
KCLT       MED   77%     HIGH  81%     HIGH  98%     HIGH 100%
KGSP       LOW   54%     MED   70%     HIGH 100%     HIGH 100%
KAVL       MED   73%     HIGH  87%     HIGH 100%     HIGH  96%
KHKY       MED   69%     MED   71%     HIGH 100%     HIGH  95%
KGMU       MED   66%     MED   76%     HIGH 100%     HIGH 100%
KAND       MED   62%     MED   64%     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...JPT
NEAR TERM...SBK
SHORT TERM...JPT
LONG TERM...JPT
AVIATION...SBK






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