Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 291438
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1038 AM EDT FRI MAY 29 2015

.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL PERSIST ACROSS THE REGION THROUGH THE
WEEKEND AND INTO EARLY NEXT WEEK. DEEPER MOISTURE WILL GRADUALLY
SPREAD ALONG THE SOUTHERN APPALACHIANS WITHIN THE SOUTHERLY FLOW
BETWEEN LOW PRESSURE APPROACHING THE MID MISSISSIPPI VALLEY FROM THE
WEST AND THE OFFSHORE BERMUDA HIGH TO THE EAST. A COLD FRONT WILL
PUSH SOUTHWARD INTO THE REGION AROUND MID WEEK AND THEN LIKELY STALL
NEARBY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1025 AM...WIDELY SCATTERED SHOWERS HAVE DEVELOPED ACROSS THE
PIEDMONT AND FOOTHILLS IN ASSOCIATION WITH REMNANT OUTFLOW AND/OR
SEA-BREEZE BOUNDARY. LATEST SHORT TERM AND HIRES GUIDANCE INDICATES
A FEW MORE WEAK BOUNDARIES WILL PUSH OVER THE AREA WITHIN SOUTHEAST
LOW LEVEL FLOW THROUGH THE NEXT 24 HOURS OR SO. SLIGHTLY DRIER AIR
IN THE WAKE OF THE CURRENT BOUNDARY IS EXPECTED TO RESULT IN RATHER
WEAK CAPE ACROSS ROUGHLY THE SOUTHEAST THIRD OF THE FORECAST AREA
THIS AFTERNOON. AS SUCH...THERE IS ALMOST NO CONVECTIVE QPF RESPONSE
IN SHORT TERM OR HIRES MODELS IN THOSE AREAS THIS AFTERNOON. EVEN
FARTHER NORTH...QPF RESPONSE IS QUITE SPOTTY. THIS IS NOT TOO
TERRIBLY SURPRISING...SINCE PWATS WILL BE QUITE A BIT LOWER THIS
PM...AS YESTERDAY/S DEEP MOISTURE PLUME CONTINUES TO DIMINISH IN
RESPONSE TO RISING HEIGHTS...AND CONSIDERABLE STRATOCU/CU IS
EXPECTED IN THE SOUTHEAST UPSLOPE FLOW. OVERALL...THE INHERITED
FORECAST IS IN VERY GOOD SHAPE...HIGHLIGHTING THE TENN BORDER
COUNTIES WITH THE HIGHEST POPS (50-60) THIS AFTERNOON...WHERE BETTER
INSTABILITY SHOULD DEVELOP IN LIGHT OF LESS CLOUD COVER THIS
MORNING. POPS TAPER DOWN TO SLIGHT CHANCE OR LESS ACROSS MUCH OF THE
PIEDMONT THIS AFTERNOON. MAX TEMPS WILL BE VERY CLOSE TO CLIMO NEAR
THE BLUE RIDGE...BUT ABOUT A CATEGORY ABOVE CLIMO IN MOST OTHER
LOCATIONS.

AS OF 650 AM...I WILL ISSUE A QUICK UPDATE TO INCREASE THE MENTION
OF FOG ACROSS THE UNIFOUR AND PORTIONS OF THE NRN UPSTATE. IN
ADDITION...I WILL REMOVE POPS THROUGH MID MORNING. TRENDS WITHIN THE
TEMP...SKY...AND WIND APPEAR ON TRACK.

AS OF 310 AM...NEAR TERM MODELS INDICATED THAT AN OLD SEA BREEZE
WILL REMAIN OVER THE PIEDMONT THROUGH SUNRISE. THE POSITION OF THE
SEA BREEZE SHOULD GENERALLY ALIGN ALONG THE I-85 CORRIDOR.  WINDS
SHOULD REMAIN CALM TO LIGHT SSW WIND THROUGH THE MORNING HOURS. HIGH
PRESSURE CENTERED OVER THE WESTERN ATLANTIC AND AN ELONGATED COLD
FRONT ACROSS THE CENTRAL CONUS SHOULD RESULT IN SE WINDS THIS
AFTERNOON AND EVENING. AS THE WINDS SHIFT THIS AFTERNOON...THE OLD
BOUNDARY IS EXPECTED TO SLIDE ACROSS THE FOOTHILLS AND EAST FACING
MTN SLOPES. THE COMBINATION OF WEAK INSTABILITY...HIGHER
DEWPOINTS...AND WEAK UPSLOPE FLOW SHOULD TRIGGER SCT SHRA AND TSRA
THIS AFTERNOON INTO THE EARLY EVENING. THE GREATEST COVERAGE SHOULD
OCCUR OVER THE NC FOOTHILLS AND NRN MTNS. HIGH TEMPERATURES ARE
FORECAST TO RANGE AT TO SLIGHTLY ABOVE NORMAL. FORECAST SOUNDINGS
INDICATE THAT STORM MOTIONS SHOULD REMAIN SIMILAR TO VALUES OBSERVED
ON THURSDAY. THEREFORE...WE WILL HIGHLIGHT THE POTENTIAL FOR SLOW
MOVING HEAVY DOWNPOURS IN THE HWO.

TONIGHT...THE FORECAST AREA WILL REMAIN OF THE WESTERN EDGE OF A H5
587 DM RIDGE...HEIGHTS WILL BEGIN TO FALL DURING THE PRE DAWN HOURS.
MILD MID LEVEL TEMPERATURES SHOULD RESULT IN STEADY STABILIZATION
AFTER SUNSET. ANY CONVECTION ACROSS THE REGION SHOULD START TO
DISSIPATE WITH LOSS OF HEATING...I WILL INDICATE IN THE POPS.
OVERALL...CONDITIONS WILL REMAIN COMPARABLE TO EARLY THIS
MORNING...LIGHT SOUTH TO CALM WINDS...WAVES OF MID AND HIGH DEBRIS
CLOUDS...AND PATCHY FOG. LOW TEMPERATURES ARE FORECAST TO RANGE FROM
THE LOW 60S WITHIN THE MTN VALLEYS TO MID 60S EAST.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 245 AM FRIDAY MORNING...THE SHORT TERM FCST PICKS UP AT 12Z ON
SATURDAY WITH UPPER RIDGING LINGERING OVER THE REGION AND A LOW
AMPLITUDE UPPER TROF GRADUALLY MAKING ITS WAY TOWARDS THE CWFA. OVER
THE REMAINDER OF THE PERIOD...THE RIDGE AXIS SLIDES FARTHER OFF THE
EAST COAST WHILE THE TROF AXIS IS EXPECTED TO BE JUST TO OUR WEST BY
EARLY MON. AT THE SFC...THE CAROLINAS WILL STILL BE UNDER THE
INFLUENCE OF THE BERMUDA HIGH WITH WEAK SLY FLOW OVER THE REGION. AN
ELONGATED FRONTAL ZONE WITH DEEP LYR MOISTURE WILL APPROACH THE CWFA
LATE SAT/EARLY SUN...HOWEVER THE MODELS ARE SLOW TO BRING THE MOIST
AIR INTO THE CWFA. ITS LOOKING LIKE THE BULK OF THE DEEPER MOISTURE
WONT SPREAD OVER THE AREA UNTIL THE END OF THE PERIOD EARLY MON.
REGARDLESS...PRECIP CHANCES ARE MINIMAL FOR SAT AND CONSIDERABLY
HIGHER FOR SUN. SFC BASED INSTABILITY LOOKS FAIRLY IMPRESSIVE ON SUN
AFTERNOON/EVENING WITH AMPLE CAPE IN THE HAIL GROWTH REGION. SHEAR
AND HELICITY ARE MINIMAL...BUT WE COULD CERTAINLY SEE NUMEROUS PULSE
TYPE SVR TS THRU THE DAY ON SUN. TEMPS ARE STILL ON TRACK TO WARM A
FEW DEGREES OVER THE PERIOD WITH HIGHS REACHING THE MID TO UPPER 80S
EACH DAY.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 310 AM FRIDAY MORNING...THE MEDIUM RANGE FCST PICKS UP AT 12Z
ON MONDAY WITH AN UPPER TROF AXIS JUST TO OUR WEST AND UPPER RIDGING
TO OUR EAST OVER THE ATLANTIC. OVER THE NEXT 48 HRS OR SO...THE TROF
AXIS WILL GRADUALLY SLIDE OVER THE CAROLINAS AND THEN LIFT NE OF THE
AREA WHILE BROAD SCALE UPPER RIDGING BEGINS TO BUILD IN THE TROFS
WAKE. AT THE SFC...A LARGE PLUME OF DEEP LYR MOISTURE ASSOCIATED
WITH A DISSIPATING FRONTAL ZONE WILL KEEP THE FCST AREA UNDER
FAVORABLE CONDITIONS FOR WIDESPREAD SHOWERS AND TS ON MON AND TUES.
BY WED...SOME DRYING IS LIKELY...ESP OVER THE NW ZONES AS THE
DEEPER MOISTURE MOVES FARTHER EAST AND THE GREAT LAKES HIGH SLIDES
FARTHER SE AND SETS UP WEDGE TYPE SFC PATTERN OVER THE FCST AREA.
THIS WEDGE IS EXPECTED TO MAINTAIN ITSELF THRU DAY 7. HIGH TEMPS
WILL COOL A FEW DEGREES MON THRU WED WITH VALUES EXPECTED TO WARM
AGAIN ON DAYS 6 AND 7.

&&

.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
AT KCLT...WINDS ARE EXPECTED TO REMAIN LIGHT TO CALM EARLY THIS
MORNING...AS THE TERMINAL REMAINS WITHIN THE AXIS OF A WEAK SFC
RIDGE. BASED ON SURROUNDING OBS...IT APPEARS THAT A PERIOD OF MVFR
CEILINGS MAY DEVELOP DURING THE FIRST ONE OR TWO HOURS OF SUNLIGHT.
OTHERWISE...SKY IS FORECAST TO REMAIN VFR...WITH PERIODS OF SCT TO
BKN CLOUDS AROUND 040 KFT. MOS AND NEAR TERM MODELS AGREE THAT WINDS
SHOULD REMAIN FROM THE SSW THROUGH MID DAY...THEN TURNING FROM THE
SSE DURING THE AFTERNOON. THE LIGHT SE LLVL FLOW SHOULD FAVOR THE
FOOTHILLS AND MTNS FOR AFTERNOON CONVECTION...I WILL KEEP THE TAF
DRY.

ELSEWHERE...SEVERAL OF THE TERMINALS RECEIVED MEASURABLE RAINFALL
THURSDAY AFTERNOON AND EVENING. AREAS WITH WET GROUND HAVE RESULTED
IN THE FORMATION OF FOG AND STRATUS BEFORE THE RELEASE OF THE 12Z
TAFS. AT KHKY...I WILL MENTION LIFR VIS AND CIGS IN THE TAF UNTIL
VFR RETURNS BY KAVL MAY KEEP LIGHT FOG THROUGH 15Z...THEN VFR. BY
THE AFTERNOON...LLVL SE FLOW SHOULD BRING A ROUND OF HUMIDITY ACROSS
THE SOUTHERN APPALACHIANS THIS AFTERNOON. I WILL HIGHLIGHT THE
CONVECTION WITH AFTERNOON PROB30 FOR KAVL AND KHKY. CONVECTION
SHOULD DISSIPATE SHORT AFTER SUNSET.

OUTLOOK...MOIST SW FLOW WILL CONTINUE TO AFFECT THE TERMINAL
FORECAST AREA THROUGH THIS WEEKEND...AS A COLD FRONT LAYS OVER TO
THE NORTH OF THE AREA. EXPECT POCKETS OF MORNING FOG AND/OR STRATUS
MOST DAYS...WITH CONTINUED CHANCES OF AFTN/EVENING SHRA/TSRA EACH
DAY.

CONFIDENCE TABLE...

            14-20Z        20-02Z        02-08Z        08-12Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  87%
KGSP       HIGH  98%     HIGH 100%     HIGH 100%     MED   79%
KAVL       HIGH  86%     HIGH 100%     MED   77%     MED   64%
KHKY       MED   70%     HIGH 100%     HIGH 100%     MED   79%
KGMU       HIGH  98%     HIGH 100%     HIGH 100%     MED   79%
KAND       HIGH  90%     HIGH 100%     HIGH 100%     MED   79%

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...JDL/NED/WIMBERLEY
SHORT TERM...JPT
LONG TERM...JPT
AVIATION...NED


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