344  
FXUS62 KGSP 301446  
AFDGSP  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC  
1046 AM EDT SAT JUL 30 2016  
   
SYNOPSIS
 
 
A TYPICAL MID-SUMMER WEEKEND IS ON TAP FOR THE REGION AS A BROAD AND  
WEAK PRESSURE PATTERN LINGERS ATOP THE SOUTHEAST. LITTLE CHANGE IN  
THE WEATHER PATTERN IS EXPECTED THROUGH THE START OF NEXT WEEK.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
AS OF 1030 AM SATURDAY: MADE SEVERAL ADJUSTMENTS MAINLY TO SKY AND  
POP GRIDS TO ACCOUNT FOR CONTINUED MIDLEVEL CLOUDINESS MOVING ACROSS  
THE PIEDMONT. STILL SEEING SOME RETURNS ACROSS THE UPSTATE WITH  
THESE CLOUDS BUT MOSTLY VIRGA AT THIS TIME. AN AREA OF CONVECTION  
THAT HAS MOVED ACROSS EASTERN TN IS RIGHT ON OUR BORDER SO HAVE  
ADJUST POPS ACROSS THE MOUNTAINS TO ACCOUNT FOR THIS. ADDITIONALLY,  
ANOTHER AREA (ACTUALLY IT'S ALL ALONG THE SAME IMPULSE) IN NORTHERN  
GA IS PRODUCING SOME SHOWERS DOWNSTREAM INTO NE GA. THE CLOUD COVER  
HAS HELD TEMPS DOWN A LITTLE MORE THAN EXPECTED BUT WITH AFTERNOON  
MIXING/CLEARING THE OVERALL HIGH TEMPS SHOULD CATCH UP. MADE TWEAKS  
TO HOURLY TRENDS WITH SOME MINOR CHANGES TO AFTERNOON HIGHS BUT  
CHANGES ARE MAINLY NEGLIGIBLE.  
 
OTHERWISE, A BROAD, YET MEDIUM AMPLITUDE H5 TROF CONTINUES TO DIG  
ACROSS THE EAST/CENTRAL CONUS, WHILE THE PERSISTENT ANTICYCLONE THAT  
HAS BEEN RESPONSIBLE FOR MANY DRY/HOT DAYS OVER THE SOUTHEAST  
FLATTENS. AT THE SURFACE OVER THE SOUTHEAST, WEAK HIGH PRESSURE  
LOOKS TO PREVAIL OVERALL, HOWEVER WITH EMBEDDED LEE TROFFING OVER  
PORTIONS OF NORTHEAST GA AND THE WESTERN CAROLINAS.  
 
THERMAL PROFILES ONCE AGAIN EXHIBIT MODEST LOW/MID LVL LAPSE  
RATES BENEATH POOR RATES IN THE MID/UPPER LEVELS, WHILE SHEAR IS  
SLIGHTLY IMPROVED FROM DAYS PAST THANKS IMPROVED FLOW AMIDST THE  
SYNOPTIC TROF. GIVEN THESE PARAMETERS, AS WELL AS AN ANALYSIS  
OF CAM COMPOSITES, THE FCST WILL FEATURE A BROAD BRUSH OF  
ISOLATED/SCATTERED THUNDERSTORMS THIS AFTERNOON, LIKELY INITIATING  
ALONG THE BLUE RIDGE BEFORE COLD POOL PROPAGATION DIRECTS SAID  
CONVECTION EAST INTO THE NC/SC PIEDMONT. GIVEN THE POOR LAPSE  
RATES ALOFT, NOT EXPECTING ANY SEVERE CONVECTION, HOWEVER A FEW  
STRONGER STORMS CANNOT BE RULED OUT. POPS WILL LOWER THROUGH THE  
EVENING INTO THE OVERNIGHT, HOWEVER LINGERING AT LOW END SLIGHT  
CHANCE LEVELS REGIONWIDE THROUGH SUNDAY MORNING. TEMPERATURES TODAY  
WILL ONCE AGAIN BE QUITE WARM, GENERALLY MID/UPPER 90S ALONG/SOUTH  
OF I85, WITH UPPER 80S TO LOWER 90S ACROSS THE NORTHERN PIEDMONT  
AND FOOTHILLS, AND UPPER 70S TO MID 80S FAVORED OVER THE HIGHER  
ELEVATIONS. DEWPOINTS ARE EXPECTED TO MIX OUT A BIT INTO THE  
AFTERNOON, HOWEVER REMAINING AT LEVELS SUPPORTIVE OF HEAT INDICES  
NEARING THE CENTURY MARK ACROSS THE SOUTHERN TIER OF THE FCST AREA.  
 

 
   
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/
 
 
AS OF 155 AM SATURDAY...AN UPPER TROUGH AXIS MOVES INTO THE AREA  
SUNDAY AND REMAINS IN PLACE ON MONDAY. A SERIES OF WEAK SHORT WAVES  
WILL ROTATE THROUGH THE TROUGH AND OVER OR NEAR THE AREA EACH DAY.  
AT THE SURFACE, A WEAK COLD FRONT MOVES TOWARD THE AREA SUNDAY WITH  
A LEE TROUGH DEVELOPING OVER THE CWFA. THE FRONT DROPS INTO THE AREA  
FOR MONDAY. ALL THIS SHOULD LEAD TO A RELATIVELY GOOD ENVIRONMENT  
FOR DEEP CONVECTION BOTH DAYS. THEREFORE, PRECIP CHANCES WILL BE  
HIGHER THEN CLIMO, BUT WITH A FAIRLY TYPICAL DIURNAL AND PLACEMENT  
TREND. CANNOT RULE OUT A FEW STRONG/SEVERE STORMS BOTH DAYS, BUT  
POOR LAPSE RATES, LOW SHEAR, AND RELATIVELY WEAK DCAPE SUGGEST  
CHANCES ARE LOW. TEMPS WILL REMAIN ABOVE NORMAL WITH LOW TO MID 90S  
COMMON BOTH DAYS. HUMIDITY WILL BE HIGH ENOUGH FOR HEAT INDEX VALUES  
TO RISE INTO THE LOW 100 RANGE, MAINLY SOUTH OF I-85.  
 

 
   
LONG TERM /TUESDAY THROUGH FRIDAY/
 
 
AS OF 320 AM SATURDAY...UPPER TROUGH AXIS OVER THE EAST COAST ON  
TUESDAY SLIDES OFF SHORE ON WEDNESDAY AS RIDGING BUILDS OVER THE  
CENTRAL CONUS. THIS KEEPS A NW FLOW OVER THE AREA THROUGH THURSDAY  
ALLOWING A SERIES OF SHORT WAVES TO MOVE THROUGH THE FLOW AND OVER  
OR NEAR THE CWFA. DIFFERENCES DEVELOP IN THE GUIDANCE BY FRIDAY,  
WITH THE ECMWF SHOWING SHORT WAVE RIDGING DEVELOPING OVER THE AREA,  
WHILE THE GFS DEVELOPS A WEAK SHORT WAVE TROUGH. A QUASI-STATIONARY  
FRONT REMAINS OVER THE AREA TUESDAY AND WEDNESDAY KEEPING A CHANCE  
OF DIURNAL CONVECTION OVER THE CWFA EACH DAY. TUESDAY IS THE DRIER  
OF THE TWO DAYS WITH ONLY ISOLATED CONVECTION EXPECTED. THE FRONT  
WASHES OUT THURSDAY BUT SOUTHERLY LOW LEVEL FLOW DEVELOPS AND  
CONTINUES INTO FRIDAY. THIS KEEPS MOISTURE AND INSTABILITY OVER THE  
AREA, RESULTING IN CONTINUED SCATTERED MAINLY DIURNAL CONVECTION  
EACH DAY. TEMPS REMAIN ABOVE NORMAL THROUGH THE PERIOD, BUT DO DROP  
TOWARD NORMAL FOR THURSDAY.  
 

 
   
AVIATION /15Z SATURDAY THROUGH WEDNESDAY/
 
 
AT KCLT: ONLY CHANGE FOR THE 15Z AMD WAS TO REMOVE VCSH UNTIL  
18Z. WINDS HAVE ALREADY STARTED VEERING MORE TO THE W AS THE LEE  
TROUGH SETS UP AGAIN SO THE WSW WINDS LOOK GOOD. OTHERWISE, VFR  
THROUGH THE PERIOD. MID/HIGH CLOUDS GIVING WAY TO FEW/SCT LOW VFR CU  
THIS AFTERNOON. PROFILES TODAY REMAIN RELATIVELY UNSTABLE IN THE  
LOW/MID LEVELS, HOWEVER EXHIBIT POOR LAPSE RATES IN THE MID/UPPER  
LEVELS WHICH WOULD LIMIT OVERALL DEPTH/INTENSITY OF TSRA. THEREFORE,  
STILL THINKING CONVECTION WILL INITIATE ABOUT THE REGION BY  
EARLY/MID AFTERNOON THEREFORE PREVIOUS PROB30 WAS DROPPED IN FAVOR  
OF A 4HR TEMPO FROM 19-23Z. WINDS WILL REMAIN LIGHT WNW/WSW THIS  
MORNING BEFORE BACKING SW BY LATE MORNING IN THE 6-8KTS RANGE.  
 
ELSEWHERE: TRENDS VERY SIMILAR TO THAT OF KCLT ABOVE, HOWEVER WITH  
EARLY RESTRICTIONS DUE TO FOG/CIGS BY WAY OF BRIEF TEMPOS AT KHKY  
AND KAVL. LIGHT SHRA IS TRYING TO ESTABLISH ITSELF ACROSS THE  
UPSTATE AT THIS TIME THUS DID DECIDE TO PREVAIL VCSH THROUGH THE  
NEXT FEW HOURS AT ALL SC SITES. OTHERWISE, MID/HIGH CLOUDS WILL  
PREVAIL THROUGH LATE MORNING BEFORE LOW VFR CU DEVELOPS AT ALL  
SITES. KEPT ALL TSRA MENTION IN BY WAY OF VCTS/PROB30 WITH TIMING  
BASED UPON LATEST CAMS. WINDS WILL REMAIN GENERALLY OUT OF THE  
WSW AROUND 6-10KTS ASIDE FOR AT KAVL WHERE WNW FLOW WILL PREVAIL.  
 
OUTLOOK: BROAD TROFFING CONTINUES TO BUILD ACROSS THE EAST/CENTRAL  
CONUS LASTING INTO MID WEEK. MOISTURE IN THE LOW/MID LEVELS  
COMBINED WITH A SERIES OF IMPULSES WORKING THROUGH THE MEAN FLOW  
ALOFT WILL YIELD CONTINUED/INCREASED CHANCES FOR SHRA/TSRA THROUGH  
MID/LATE WEEK. AS SUCH, RESTRICTIONS ASSOCIATED WITH SHRA/TSRA  
ARE POSSIBLE, AS WELL AS EARLY MORNING FOG/CIGS.  
 
CONFIDENCE TABLE...  
 
14-20Z 20-02Z 02-08Z 08-12Z  
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%  
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%  
KAVL HIGH 88% HIGH 100% HIGH 100% MED 70%  
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 87%  
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%  
KAND HIGH 100% HIGH 100% 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:  
 
WWW.WEATHER.GOV/GSP/AVIATION  
 

 
   
GSP WATCHES/WARNINGS/ADVISORIES
 
 
GA...NONE.  
NC...NONE.  
SC...NONE.  
 

 
 

 
SYNOPSIS...RWH  
NEAR TERM...CDG/TDP  
SHORT TERM...RWH  
LONG TERM...RWH  
AVIATION...CDG/TDP  
 
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