Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 030747
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
347 AM EDT FRI JUL 3 2015

.SYNOPSIS...
A BROAD UPPER LEVEL TROUGH WILL REMAIN OVER THE SOUTHEAST THROUGH
MONDAY...STEERING A SERIES OF WEAK DISTURBANCES OVER THE REGION.
THESE FEATURES WILL INCREASE RAIN AND THUNDERSTORM CHANCES EACH
AFTERNOON AND EVENING...AND KEEP SKIES CLOUDIER THAN USUAL. SLIGHT
DRYING WILL OCCUR TUESDAY...BEFORE ANOTHER FRONT PUSHES THROUGH IN
THE MIDDLE OF THE WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 315 AM EDT FRIDAY...THE UPPER PATTERN THIS MORNING IS
HIGHLIGHTED BY A BROAD/DEEP TROF OVER THE EASTERN CONUS.  A RATHER
POTENT SHORTWAVE TROF WILL CONTINUE TO EJECT THROUGH THE MEAN FLOW
ALOFT ACROSS THE MIDWEST...INTO THE OH/TN VALLEYS DURING THE NEAR
TERM FCST PERIOD.  MEANWHILE AT THE SURFACE...AN AXIS OF CONVERGENCE
EXTENDS IN AN EAST/WEST ORIENTATION IN PROXIMITY TO THE I40 CORRIDOR
OVER WEST/MIDDLE TN WESTWARD INTO AR/MO.  THIS BOUNDARY CONTINUES TO
PROVIDE ENOUGH LIFT FOR CONVECTION THIS MORNING OVER THE TN VALLEY
REGION AND WILL CONTINUE ADVECTING EAST INTO WESTERN NC AND
NORTHEAST GA...BEFORE SPREADING INTO THE FOOTHILL/PIEDMONT REGIONS
OF NC/SC AROUND OR JUST AFTER DAYBREAK.  THUS POPS ARE FAIRLY
HEALTHY FOR RUSH HOUR WITH LIKELY LEVELS FAVORED ALONG THE I85/I26
CORRIDORS...WITH HIGH LEVEL CHANCE POPS FAVORED EAST OVER CLT AND
THE I77 CORRIDOR.

FOR THE AFTERNOON/EVENING...MODELS FAVOR THE NORTHERN TIER OF THE
FCST AREA AS THEY SEEM TO BE CUTTING DOWN INSTABILITY OVER THE
SOUTHERN TIER THANKS TO THE ONGOING/MORNING CONVECTION.  WOULD NOT
BE SURPRISED IF THERE IS SOME DIFFERENTIAL HEATING...HOWEVER THINK
THE CAPE FIELDS THIS AFTERNOON MIGHT BE A BIT MORE HOMOGENEOUS THAN
THE GUID LEADS ON AS SKIES WILL BE PARTLY/MOSTLY CLOUDY REGIONWIDE.
SOUNDINGS DO EXHIBIT ENOUGH INSTABILITY/SHEAR TO SUPPORT STRONG TO
PERHAPS ISOLATED SEVERE THUNDERSTORMS THAT COULD PRODUCE ISOLATED
DAMAGING GUSTS/HAIL.  MOST IMPRESSIVE HOWEVER CONTINUES TO BE PWATS
APPROACHING/EXCEEDING 2IN LEADING TO CONTINUED ISOLATED FLASH
FLOODING THREATS...ALL OF WHICH WILL BE HIGHLIGHTED IN THE HWO.  AS
FOR THE FCST...LIKELY POPS PERSIST ACROSS MUCH OF NORTHEAST GA AND
THE UPSTATE THIS AFTERNOON...WITH AN INCREASING GRADIENT NORTHWARD
TO CATEGORICAL POPS NORTH OF I40.  COVERAGE WILL DECREASE INTO THE
EVENING/OVERNIGHT HOURS AS BEST UPPER FORCING AND CONSEQUENT SURFACE
WAVE EJECT TO THE EAST...THEREFORE POPS WILL FALL OFF AS WELL.
TEMPERATURES THROUGH THE NEAR TERM WILL REMAIN BELOW NORMAL AS
CLOUDY SKIES LIMIT HEATING.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 315 AM FRI...AS UPPER TROUGH SWINGS ACRS THE SRN APPALACHIANS
SATURDAY...SFC LOW IS PUSHED OFF THE MID-ATLANTIC COAST. HOWEVER THE
BASE OF THE TROUGH CONCURRENTLY SHEARS OFF LEAVING A SLOW-MOVING
SHORTWAVE TO LINGER OVER OUR REGION INTO EARLY MONDAY. SOME SEMBLANCE
OF THE FRONT WILL REMAIN ACROSS THE CAROLINAS...AND THOUGH IT IS
INITIALLY HARD TO IDENTIFY ANY DISTINCT SOURCE OF FORCING...WEAK
CONVERGENCE SHOULD ENHANCE PRECIP CHANCES IN ADDITION TO EMBEDDED
VORTICES HIGHER ALOFT. ON SUNDAY THE BOUNDARY IS STRENGTHENED AS HIGH
PRESSURE BUILDS EWD IN THE WAKE OF THE LARGER SCALE TROUGH. DEEP
MOISTURE WILL REMAIN IN PLACE BOTH DAYS AND ROUNDS OF HEAVY RAIN WILL
CONTINUE...WITH PWAT VALUES BEING ABOVE THE 90TH PERCENTILE AT TIMES.
WINDS ALOFT WILL RELAX AS THE LOW PULLS AWAY SATURDAY...AND PROFILES
WILL REMAIN UNIDIRECTIONAL THRU THE PERIOD...SO SLOW MOVING AND/OR
TRAINING CELLS WILL BE A CONCERN. POPS AND QPF ARE EXPECTED TO BE
HIGHER SUNDAY ON ACCOUNT OF THE ENHANCED LLVL CONVERGENCE. CLOUD
COVER WILL LIMIT TEMPS TO ABOUT A CATEGORY BELOW CLIMO.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 130 AM FRIDAY...THE UPPER PATTERN BEGINS TO DEAMPLIFY OVER THE
CWFA MONDAY AS A SHORTWAVE PASSES THRU ONTARIO...GRADUALLY ABSORBING
THE STAGNANT UPPER LOW OVER THE SRN APPALACHIANS. THIS FEATURE WILL
HOWEVER STILL BE IN PLACE TO MAINTAIN ELEVATED POPS MONDAY...WITH
CLOUDY CONDITIONS KEEPING TEMPS A CATEGORY OR SO BELOW NORMAL.
HEIGHTS RISE INTO MIDWEEK...ALLOWING POPS TO FALL BACK TO A TYPICAL
CLIMATOLOGICAL RANGE. HOWEVER THE PATTERN REMAINS UNSETTLED ENOUGH TO
PRECLUDE A NORMAL NOCTURNAL MINIMUM. A COLD FRONT ASSOC WITH THE
CANADIAN LOW STALLS OVER THE TENN VALLEY WED OR WED NIGHT. GFS
DEPICTS THE FRONT HANGING UP IN THAT AREA AS THE BERMUDA HIGH
RETROGRADES SLIGHTLY. EC DIFFERS IN THAT THE FRONT ENTERS OUR AREA
JUST AS A SHORTWAVE CROSSING THE MID MISSISSIPPI VALLEY BEGINS TO
LIFT IT NWD AS A WARM FRONT. GFS IS THUS MORE UNSETTLED FOR THU
COMPARED TO THE EC. HOWEVER...THE EC SHOWS LOW PRESSURE MOVING ACRS
TO OUR NORTH THU NIGHT AND PULLING THE BOUNDARY ACRS THE SRN
APPALACHIANS AT THAT TIME. THE RETURN TO SWLY FLOW AROUND THE BERMUDA
HIGH WILL LEAD TO A GRADUAL WARMING TREND IN TEMPS...WITH AFTN MAXES
BEING SLIGHTLY ABOVE NORMAL BY THU.

&&

.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
AT KCLT...UNSETTLED TAF PERIOD AHEAD AS ROUNDS OF RESTRICTIONS
PREVAIL THROUGH THE OVERNIGHT AND THROUGH THE DAY ON FRIDAY.
INITIALIZED TAF AMIDST BKN IFR CIGS AND LIGHT SW WINDS AS STRATUS
CONTINUES TO SPREAD IN THE VERY MOIST PBL.  MODELS PROG SCATTERED
SHRA AROUND THE REGION SHORTLY AFTER DAYBREAK ASSOCIATED WITH AN
APPROACHING UPPER SHORTWAVE AND ASSOCIATED SURFACE LOW TO THE
NORTH.  THUS...INTRODUCED VCSH AT 13Z WITH A SLIGHT IMPROVEMENT TO
MVFR FOR CIGS.  BY LATE MORNING WINDS ARE EXPECTED TO INCREASE AHEAD
OF LLJ INTRUSION LEADING TO GUSTING...ALONG WITH PREVAILING SHRA AND
A PROB30 FOR AFTERNOON THUNDERSTORMS.

ELSEWHERE...MUCH THE SAME AS KCLT ABOVE HOWEVER WITH SLIGHT TIMING
ADJUSTMENTS.  INITIALIZED ALL TAFS WITH LIGHT/CALM SW WINDS UNDER
MIXED STRATUS DECKS WITH THE SC SITES GETTING IFR SCT LAYERS.
INTRUDING CONVECTION TO THE WEST AT THIS TIME WARRANTS OVERNIGHT
MENTION OF SHOWERS THEREFORE CARRIED VCSH AT ALL SITES BY 8Z-9Z
ASIDE FOR KHKY WHERE ONSET WILL BE CLOSER TO DAYBREAK.  BEYOND
THAT...PRECIP CHANCES INCREASE FURTHER WITH ALL SITES SEEING
PREVAILING SHRA WITH VCTS AND OR PROB30S FOR THUNDERSTORMS IN THE
AFTERNOON.  WINDS WILL BE QUITE GUSTY ON FRIDAY AT THE SC SITES AND
KAVL...LESS SO AT KHKY...ALL THANKS TO STRONG LLJ DEVELOPMENT WHICH
GUIDANCE FAVORS AT AROUND 40KTS/5KFT.

OUTLOOK...A LINGERING FRONTAL BOUNDARY WILL PERSIST THROUGH THE
WEEKEND INTO THE START OF THE NEXT WORK WEEK.  THIS WILL LEAD TO
ON/OFF CHANCES FOR SHOWERS EACH DAY...ENHANCED DIURNALLY.
AFTERWARDS...THE PATTERN BECOMES INCREASINGLY DIURNAL FOR THE
REMAINDER OF THE WEAK.  RESTRICTIONS WILL BE POSSIBLE ASSOCIATED
WITH CONVECTION...AND ALSO EACH MORNING ATOP RAIN SOAKED AREAS.

CONFIDENCE TABLE...

            07-13Z        13-19Z        19-01Z        01-06Z
KCLT       HIGH  84%     HIGH  86%     HIGH  97%     HIGH 100%
KGSP       HIGH  85%     HIGH  84%     HIGH 100%     HIGH 100%
KAVL       HIGH  92%     HIGH  96%     HIGH 100%     HIGH 100%
KHKY       MED   76%     MED   76%     HIGH  97%     HIGH 100%
KGMU       HIGH  86%     HIGH  82%     HIGH 100%     HIGH 100%
KAND       MED   70%     HIGH  86%     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...WIMBERLEY
NEAR TERM...CDG
SHORT TERM...WIMBERLEY
LONG TERM...LEV/WIMBERLEY
AVIATION...CDG



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