Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 021431
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1031 AM EDT THU JUL 2 2015

.SYNOPSIS...
A BROAD UPPER LEVEL TROUGH WILL REMAIN OVER THE SOUTHEAST THROUGH
THE WEEKEND...STEERING A SERIES OF WEAK LOW PRESSURE SYSTEMS OVER
THE REGION. THESE SYSTEMS WILL INCREASE RAIN AND THUNDERSTORM
CHANCES EACH AFTERNOON AND EVENING. HIGH TEMPERATURES WILL BE NEAR
NORMAL THROUGH NEXT WEEK...WITH LOWS JUST ABOVE NORMAL.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM EDT...LIGHT TO MODERATE SHOWERS CONTINUE TO ROUND THE
TROUGH AXIS TO THE WEST AND CROSS THE WESTERN HALF OF THE FORECAST
AREA THIS MORNING. ADDITIONAL...STRONGER SHOWERS AND TSTMS HAVE
DEVELOPED FROM TYS TO N OF CHA ON THE STRENGTH OF A MORNING MCS
OUTFLOW AND ALSO WITH APPROACHING UPPER SHORTWAVE SUPORT IN THE
BROADER SCALE TROUGH AXIS STRETCHED FROM THE OH VALLEY TO THE DEEP
SOUTH. STEERING FLOW WILL CARRY THIS ACTIVITY INTO THE WRN NC
MTNS...WITH THE HEAVIEST RATES LIKELY IN THE SW MOUNTAINS NEAR THE
SMOKIES. HYDRO CONCERNS WILL THUS STEADILY INCREASE...BUT THIS MAY
JUST PRIMING THE PUMP FOR ANY ADDITIONAL HEAVY RAINFALL THROUGH
FRIDAY. WILL AWAIT THE FULL SUITE OF 12Z MODEL DATA BEFORE DECIDING
ON ANY FLOOD WATCHES SINCE THE RATES HAVE BEEN FAIRLY TAME THUS FAR.

OTHERWISE...A SURFACE FRONT IS EXPECTED TO REMAIN STALLED JUST TO
OUR NORTH WITH LOW PRESSURE SLIDING EASTWARD ALONG THE BOUNDARY.
CLOUD COVER WILL LIMIT HEATING AND INSTABILITY...AND WITH LIMITED
SHEAR AND LITTLE DRY AIR ALOFT FOR EVAPORATIVE COOLING...CONVECTION
IS EXPECTED TO SOMEWHAT TAME. RAINFALL COULD BE SOMEWHAT ROBUST AS
MENTIONED PREVIOUSLY...BUT STEERING FLOW SHOULD KEEP CELLS
MOVING...AND LOW LEVEL FLOW PARALLEL TO THE BLUE RIDGE WILL LIMIT
ANY UPSLOPE ANCHORING. HIGH TEMPERATURES WILL RUN ONE TO TWO
CATEGORIES BELOW NORMAL UNDER CLOUDS...BUT MINIMUM TEMPERATURES
CLOSER TO CLIMO DUE TO MOISTURE.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
OF 240 AM THURSDAY...THE SHORT TERM FCST PICKS UP AT 12Z ON
FRIDAY WITH THE UPPER TROF FLATTENING OUT WHILE NUMEROUS LOBES OF
SHORTWAVE ENERGY STREAM ACROSS THE FCST AREA FROM THE WEST.

ON FRIDAY...DEEP LYR MOISTURE WILL BE IN PLACE OVER THE REGION FRI
MORNING AS A COMPLEX SFC LOW DEVELOPS JUST TO THE NORTH. AS THE LOW
SLOWLY MOVES TOWARDS THE COAST...ANOTHER LEE TROF WILL SET UP OVER
THE CAROLINAS LATE FRI AND LINGER WELL INTO SAT. POPS STEADILY RAMP
UP THRU THE DAY/EVENING WITH HIGH END CHANCE TO LIKELY VALUES
CARRIED OVER THE ENTIRE CWFA BY THE AFTERNOON. QPF AMOUNTS HAVE BEEN
LOWERED A BIT SINCE YESTERDAYS FCST...HOWEVER A SOLID INCH OR SO IS
POSSIBLE OVER SOME OF THE UPSLOPE AREAS AND HIGHER TERRAIN. SPC
KEEPS OUR CWFA IN THE MARGINAL RISK AREA WITH THE BIGGEST THREAT
BEING SVR STRAIGHT LINE WINDS. AS WE MOVE INTO SAT...THE SFC
LOW BEGINS TO MOVE OFF THE COAST AND ANOTHER LEE TROF DEVELOPS IN
ITS WAKE KEEPING WINDS OUT OF THE SW AND TIGHTENING THE PRESSURE
GRADIENT. PW VALUES WILL REMAIN HIGH THRU SAT...SO FLASH FLOODING
CONTINUES TO BE A CONCERN GOING FORWARD. TEMPS START OUT ABOUT 2 TO
4 DEGREES BELOW CLIMO ON FRI AND WARM A FEW DEGREES OVER THE NEXT
FEW DAYS ENDING RIGHT AROUND NORMAL FOR EARLY JULY.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
OF 240 AM THURSDAY...THE MEDIUM RANGE FCST PICKS UP AT 12Z ON
SUNDAY WITH HEIGHTS RISING AS BROAD UPPER RIDGING DEVELOPS OVER MUCH
OF THE SOUTHERN CONUS. THE MODELS GENERATE NUMEROUS WEAK UPPER
SHORTWAVES THRU THE PERIOD WITH WEAK UPPER WINDS PREVAILING THRU DAY
7. NO SIGNIFICANT PATTERN CHANGES ARE EXPECTED THRU THE MEDIUM RANGE
WITH RIDGING REMAINING IN PLACE WELL BEYOND DAY 7. AT THE SFC...THE
REGION WILL REMAIN UNSETTLED THRU MOST OF THE PERIOD WITH PREVAILING
SOUTH TO SWLY LOW LVL FLOW. THE CWFA IS EXPECTED TO REMAIN UNDER
WEAK LEE TROFFING ON SUN AND MON AS A SERIES OF SHORT LIVED MESO
LOWS ATTEMPT TO SPIN UP OVER THE CAROLINAS. THE LONG RANGE GUIDANCE
SUGGESTS THAT A MORE SUBSTANTIAL FRONT WILL APPROACH THE FCST AREA
FROM THE WEST ON WED AND THURS...HOWEVER THE STRENGTH AND TIMING OF
THE SYSTEM IS UNCLEAR. THE MODELS AGREE THAT DEEPER LYR MOISTURE WILL
PERSIST OVER THE REGION THRU MOST OF THE PERIOD WITH THE HIGHEST PW
VALUES GENERALLY OVER THE NORTHERN ZONES EARLY IN THE PERIOD AND
THEN SHIFTING SOUTHWARD ON MON AND TUES. AS FOR THE SENSIBLE
FCST...I KEPT DIURNAL HIGH END CHANCES FOR CONVECTION EACH
DAY/EVENING WITH SOME LIKELY POPS OVER THE NC/TENN BORDER REGION FOR
SUN. TEMPS START OUT AROUND CLIMATOLOGY ON SUN AND WARM SLIGHTLY
OVER THE NEXT FEW DAYS WITH HIGHS TOPPING OUT JUST ABOVE CLIMO BY
EARLY NEXT WEEK.

&&

.AVIATION /15Z THURSDAY THROUGH MONDAY/...
AT KCLT...ANY LOWER STRATUS UNDER THE ALTOCUMULUS DECK HAS MANAGED
TO STAY WELL SW OF KCLT THIS MORNING...AND BREAKS GOING FORWARD
SHOULD PERMIT HEATING AND A VFR CUMULUS FIELD UNDER LINGERNIG
MID/HIGH CLOUDS. THE HRRR CONTINUES TO ADVERTISE SHRA/TSRA MAKING A
RUN EASTWARD FROM THE BLUE RIDGE MID AFTN SO WILL STAY ON COURSE
WITH TEMPO TSRA STARTING 19Z. WINDS WILL FAVOR THE SW...WITH DAYTIME
GUSTS DUE TO MIXING. GUIDANCE BRINGS MVFR CIGS TOWARD KCLT AT
DAYBREAK FRIDAY...BUT FOR NOW CONFIDENCE IS LOW ENOUGH TO KEEP A LOW
VFR CIG AT THE FIELD.

ELSEWHERE...A BAND OF IFR TO LOWER MVFR STRATUS DEVELOPED UNDER THE
ALTOCUMULUS DECK THIS MORNING...BUT BREAKS ALOFT ARE ALLOWING SOME
HEATING AND SCATTERING. OTHERWISE...SHOWERS WILL AFFECT MAINLY KAVL
TO NEAR KGSP TO KHKY THROUGH EARLY AFTN...BUT WITH THE HRRR SHOWING
BETTER CONVECTION SWEEPING EAST OFF THE MTNS THIS AFTN. WILL
CONTINUE TO HOLD ONTO PROB OR VCTS EAST OF THE MTNS...WITH TEMPO
TSRA AT KAVL AFTER 17Z. LIMITED INSTABILITY WILL MEAN LOW CHANCES
FOR SEVERE WEATHER...BUT A MOIST ATMOSPHERE COULD SUPPORT MODERATE
RAINFALL AT TIMES. WINDS WILL FAVOR THE SW WITH DAYTIME
GUSTS...EXCEPT AT KAVL WHERE WINDS WILL CHANNEL UP THE VALLEY FROM
THE NW. PREFERRED GUIDANCE KEEPS VSBY VFR FRIDAY MORNING...BUT MOVES
MVFR CIGS IN WELL BEOFRE DAWN.

OUTLOOK...A GRADUALLY WEAKENING UPPER TROUGH WILL SUPPORT MAINLY
AFTERNOON AND EVENING THUNDERSTORMS THROUGH EARLY NEXT WEEK.
RESTRICTIONS MAY OCCUR WITH PASSING STORMS...AND EACH MORNING OVER
RAIN SOAKED AREAS.

CONFIDENCE TABLE...

            14-20Z        20-02Z        02-08Z        08-12Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  93%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     MED   74%
KAVL       HIGH  98%     HIGH 100%     HIGH  96%     MED   69%
KHKY       HIGH 100%     HIGH 100%     HIGH 100%     MED   65%
KGMU       HIGH  98%     HIGH 100%     HIGH 100%     MED   76%
KAND       HIGH 100%     HIGH 100%     MED   78%     MED   76%

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...JAT
NEAR TERM...HG/JAT
SHORT TERM...JPT
LONG TERM...JPT
AVIATION...HG/JAT



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