Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 031504
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1104 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 1045 AM EDT...THE FIRST WAVE OF CONVECTION TODAY HAS ALREADY
TRAVERSED NE GA...THE SRN TIER...AND THE WESTERN UPSTATE AND LEFT
GENERALLY STABLE AIR IN PLACE UNDER A DECAYING STRATIFORM
PRECIPITATION REGION. THE ASSOCIATED OUTFLOW...HOWEVER...IS JUST
PUSHING EAST INTO THE EASTERN UPSTATE AND CLT METRO AREA...AND
COVERAGE IS EXPECTED TO INCREASE IN THAT REGION. ANY TRAINING HEAVY
RAIN PRODUCING CELLS THIS AFTN SHOULD STAY S OF THE FORECAST AREA IN
THE BETTER INSTABILITY...SO NO SHORT FUSE FLASH FLOOD WATCHES WILL
BE NEEDED. HOWEVER...CONSIDERATION WILL BE GIVEN TO PERHAPS A LARGER
AREA/LONGER DURATION WATCH THIS AFTERNOON FOR THE UPCOMING WEEKEND.
TEMPS HAVE BEEN LOWERED AT LEAST TWO DEGREES IN MOST AREAS GIVEN THE
PRECIPITATION AND CLOUDS.

OTHERWISE...THE UPPER PATTERN CONTINUES TO BE HIGHLIGHTED BY A
BROAD/DEEP TROUGH OVER THE EASTERN CONUS...WITH VARIOUS SHORTWAVES
MOVING THROUGH THE APPALACHIANS AND AFFECTING THE FORECAST AREA.
MOST IMPRESSIVE CONTINUES TO BE PWATS APPROACHING/EXCEEDING 2IN
LEADING TO A CONTINUED ISOLATED FLASH FLOODING THREAT...CURRENTLY
HIGHLIGHTED IN THE HWO. LIKELY TO CAT POPS WILL PERSIST ACROSS THE
WRN CWFA FOR THE ARRIVAL OF UPSTREAM ACTIVITY FROM TIME TO TIME
THROUGH THE NEAR TERM. COVERAGE WILL DECREASE INTO THE EVENING/EARLY
OVERNIGHT HOURS...BUT COULD MAKE A COMEBACK FROM THE SW TOWARD
DAYBREAK. 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 /15Z FRIDAY THROUGH TUESDAY/...
AT KCLT...ISOLD CONVECTION IS STARTING TO FIRE AHEAD OF THE
STRATIFORM RAIN REGION DIMINISHING AS IT APPROACHES FROM THE WEST.
THE TAF HAS THUS BEEN ADJUSTED TO BRING A TEMPO TSRA THREAT IN AT
16Z WITH GENERALLY SHRA BEYOND 20Z. ANTICIPATE STEADY SW WINDS...BUT
WITH GUSTS DEVELOPING THROUGH THE AFTN HOURS AND NEAR ANY TSTMS.
CONDITIONS WILL IMPROVE BEYOND 00Z AS THE PRIMARY SHORTWAVE FORCING
AND SURFACE WAVE EJECT NORTHEAST.

ELSEWHERE...KAVL AND THE UPSTATE TAF SITES HAVE BEEN WORKED OVER
THIS MORNING AND IT WOULD BE A SURPRISE TO SEE MUCH ADDITIONAL
THUNDER DEVELOP THERE. HOWEVER...SHRA WILL BE WIDESPREAD AND IFR TO
MVFR CIGS WILL TAKE ADDITIONAL TIME TO SCATTER INTO EARLY AFTN. THE
STABILIZED ATMOSPHERE SHOULD ALSO KEEP ADDITIONAL ACTIVITY ARRIVING
FROM THE WEST FROM BECOMING TOO ROBUST. EXPECT INCREASING SW WIND
GUSTS AT THE UPSTATE SITES. COVERAGE MAY IMPROVE NEAR KHKY THROUGH
THE AFTN HOURS AS THE NC FOOTHILLS HAVE NOT BEEN NEARLY AS WORKED
OVER. WINDS WILL BE LIGHTER AND IFR TO MVFR CIGS COULD GET MORE
LOCKED IN THERE IF THE RAIN SHIELD ARRIVES SOON ENOUGH. EXPECT A
LULL IN ACTIVITY THIS EVENING BEFORE PRECIP ARRIVES AGAIN FROM THE
SW LATE TONIGHT.

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 WEEK. RESTRICTIONS WILL BE POSSIBLE ASSOCIATED WITH
CONVECTION...AND ALSO EACH MORNING ATOP RAIN SOAKED AREAS.

CONFIDENCE TABLE...

            15-21Z        21-03Z        03-09Z        09-12Z
KCLT       HIGH  83%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH  87%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       HIGH  90%     HIGH  94%     HIGH 100%     LOW   57%
KHKY       HIGH  81%     HIGH 100%     HIGH 100%     MED   71%
KGMU       HIGH  87%     HIGH 100%     HIGH 100%     HIGH 100%
KAND       HIGH  94%     HIGH 100%     HIGH  85%     MED   69%

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/HG
SHORT TERM...WIMBERLEY
LONG TERM...LEV/WIMBERLEY
AVIATION...CDG/HG


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