482  
FXUS62 KGSP 250227  
AFDGSP  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC  
1027 PM EDT TUE MAY 24 2016  
   
SYNOPSIS
 
 
HIGH PRESSURE WILL PREVAIL OVER THE SOUTHEAST MOST OF THIS WEEK. A  
MOIST SOUTHERLY FLOW WILL DEVELOP IN MID WEEK, WHICH WILL  
LEAD TO WARMER TEMPERATURES AND MAINLY AFTERNOON CHANCES OF SHOWERS  
AND THUNDERSTORMS EACH DAY THROUGH FRIDAY.  
 

 
   
NEAR TERM /THROUGH WEDNESDAY/
 
 
AS OF 1030 PM EDT: MINOR ADJUSTMENTS HAVE BEEN MADE TO LOWER  
PIEDMONT/FOOTHILL MINIMUM TEMPERATURES A DEGREE OR SO OVERNIGHT  
GIVEN THE GOOD RADIATIVE COOLING THUS FAR THIS EVENING. HOWEVER,  
STILL ANTICIPATE THAT MID LEVEL MOISTURE WILL SLOWLY INCREASE FROM  
THE WEST WITH AN APPROACHING UPPER SHORTWAVE - WITH ADDITIONAL  
SCATTERED STRATOCUMULUS POSSIBLY FANNING OUT IN NARROW MOISTURE  
BELOW A WEAK 800 MB INVERSION. THE INCREASING MOUNTAIN CLOUDS SHOULD  
KEEP MOST VALLEY FOG AT BAY BUT WITH THE BEST CHANCE OF FOG IN THE  
SOUTHWEST MOUNTAIN VALLEYS.  
 
WEAK SOUTHERLY FLOW AROUND THE PERIPHERY OF THE WESTERN ATLANTIC  
SURFACE HIGH WILL CONTINUE TO BRING MOISTURE INTO THE AREA THROUGH  
WEDNESDAY. THIS WILL HELP PUSH MAX TEMPS A COUPLE OF DEGREES WARMER  
ON WEDNESDAY AFTERNOON. ENOUGH DEEP-LAYER MOISTURE AND WEAK LIFT  
WILL ALSO ARISE OVER THE MOUNTAINS FOR SLIGHT TO LOW CHANCES OF  
THUNDER WEDNESDAY AFTERNOON. GIVEN THE INCREASE IN AFTERNOON  
CUMULUS, SBCAPE SHOULD BE LIMITED WITH GENERALLY LESS THAN 500 J/KG  
WITH SLIGHTLY HIGHER AMOUNTS LOCALIZED OVER THE PEAKS. THE MAIN  
THREAT WOULD BE WITH CLOUD-TO-GROUND LIGHTNING.  
 

 
   
SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/
 
 
AS OF 230 PM TUESDAY: THE SHORT TERM FCST PERIOD INITIALIZES  
WEDNESDAY EVENING AMIDST A BROAD, YET SLOWLY WEAKENING UPPER RIDGE  
CENTERED OVER THE SOUTHEAST STATES, WHILE A LARGE H5 TROF DIGS OVER  
THE DESERT SOUTHWEST. AT THE SURFACE, HIGH PRESSURE OVER THE  
WESTERN ATLANTIC WILL CONTINUE TO PROMOTE WEAK SOUTHERLY WAA ACROSS  
THE SOUTHERN APPALACHIANS AS CYCLOGENESIS GETS UNDERWAY AHEAD OF THE  
A FORE MENTIONED H5 TROF ATOP WESTERN KS/OK/TX. CLOSER TO HOME, A  
WEAK SHORTWAVE IMPULSE RIDING THROUGH THE APEX OF THE UPPER RIDGE  
COMBINED WITH AMPLE LLV DESTABILIZATION WILL HAVE RESULTED IN  
ISO/SCT SHRA AND TSRA OVER THE NC HIGH TERRAIN BY 00Z WEDNESDAY.  
WITH THAT, PROFILES ARE INDICATIVE OF PULSE TYPE CONVECTION AMIDST  
WEAK FLOW THROUGHOUT THE COLUMN AND EVER IMPROVING DEEP LAYER  
MOISTURE. PWATS AREN'T ALL THAT IMPRESSIVE, GENERALLY 1.25-1.5  
INCHES AT BEST, HOWEVER GIVEN THE WEAK FLOW AND MODESTLY ELEVATED  
LCLS, THINK THE PRIMARY CONVECTIVE CONCERN WILL BE WET MICROBURSTS  
AS WELL AS ISOLATED FLASH FLOODING AMIDST ANY SLOW MOVING  
HEAVIER/DEEPER CONVECTION.  
 
MOVING ALONG THROUGH THE PERIOD, NOT MUCH CHANGE SYNOPTICALLY ON  
THURSDAY AND FRIDAY AS THE SUBTROPICAL RIDGE PERSISTS OVER THE  
SOUTHEAST CONUS, WITH CONTINUED SOUTHERLY WAA AT THE SURFACE.  
PRECIPITATION CHANCES REMAIN ELEVATED OVER THE HIGH TERRAIN WHERE  
ANY INHIBITION WILL BE WEAKEST EACH DAY ALLOWING FOR MORE WIDESPREAD  
INITIATION WITH HEATING. AS FOR THE REMAINDER OF NORTHEAST GA AND  
THE WESTERN CAROLINAS, PRECIPITATION CHANCES WILL BE LOWER THROUGH  
THE PERIOD RELATIVE TO THE MTNS GIVEN PROXIMITY TO THE RIDGE CENTER,  
HOWEVER SAID CHANCES DO INCREASE WITH TIME AS GUIDANCE FAVORS  
GENERALLY UNSTABLE AND UNCAPPED PROFILES BOTH THURSDAY/FRIDAY WITH  
IMPROVING PWATS AND WEAK FLOW ALOFT. ALL SAID, THE THREAT FOR PULSE  
CONVECTION INDUCED FLASH FLOODING WILL INCREASE OVER THE NC MTNS  
GIVEN DEGRADING ANTECEDENT CONDITIONS EACH DAY. ANTECEDENT  
CONDITIONS OVER THE PIEDMONT REGIONS WILL ALSO BE DEGRADED WITH  
TIME, HOWEVER RELATIVELY LESS THAN THAT OF THE MTNS, YET STILL  
PRESENTING A NON ZERO THREAT FOR HYDRO ISSUES. LASTLY, GUIDANCE  
CONTINUES TO INDICATE, ALTHOUGH WITH SOME DISCONTINUITY REGARDING  
THE DETAILS, THAT A WEAK TROPICAL LOW IS TO FORM/STRENGTHEN OVER THE  
WESTERN ATLANTIC AND EVENTUALLY APPROACH THE SOUTHEAST COAST ON  
FRIDAY EVENING. ALTHOUGH ANY SPECIFIC IMPACTS FROM THIS FEATURE ARE  
BEYOND THE SCOPE OF THIS FCST TIME FRAME, IT SHOULD BE NOTED THAT  
FLOW OVER THE SOUTHEAST DOES LOOK TO BACK AS THE SYSTEM APPROACHES.  
THIS COULD YIELD IMPROVING UPSLOPE FLOW CONDITIONS ALONG THE BLUE  
RIDGE FOR FRIDAY.  
 

 
   
LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/
 
 
AS OF 2 PM TUESDAY: AN UPPER RIDGE EAST OF THE MISSISSIPPI AND  
BROAD UPPER TROUGH TO THE WEST ON ALL MODELS AT 00Z SATURDAY. THE  
RIDGE BROADENS OVER THE WEEKEND AND INTO THE FIRST HALF OF NEXT WEEK  
AS TROPICAL MOISTURE MOVES TOWARD THE CAROLINAS FROM THE BAHAMAS.  
DIURNAL CONVECTION IS EXPECTED EACH PM BUT SO MUCH DEPENDS ON WHERE  
THIS TROPICAL MOISTURE ENDS UP. THE GFS IS STILL BRINGING THE WEAK  
LOW MORE TO THE WEST THAN THE ECMWF. THE GFS GIVES THE WESTERN  
CAROLINAS AND NE GA TROPICAL RAINS LATE SUNDAY INTO THE FIRST HALF  
OF THE WEEK WHILE THE ECMWF HAS US MOSTLY DRY. NATIONAL GUIDANCE  
REMAINS OF OPINION THAT ORGANIZED TROPICAL DEVELOPMENT HAS LOW  
CHANCE. 7 DAY RAIN TOTAL GUIDANCE ARE NOW SHOWING UPSLOPE  
ENHANCEMENT RAINFALL OF AT LEAST 1.5 ALONG EASTERN ESCARPMENT. GFS  
NOW TAKES THE WEAK TROPICAL LOW UP I-26 FROM SUNDAY EVENING TO THE  
NC MTNS ON TUESDAY. WHENEVER THERE IS A NAMED TC, THE FIRST ONE  
WILL BE NAMED ALEX AND SECONDLY BONNIE. THAT MAY TAKE A WHILE THOUGH.  
 
LOW LEVEL WIND FLOW WILL DEPEND GREATLY ON THE TRACK OF THE  
COUNTERCLOCKWISE CIRCULATION OF LOW PRESSURE. THE ECMWF HAS MOSTLY  
LIGHT AND VARIABLE ON SATURDAY THEN EAST AND NE SUNDAY INTO TUESDAY  
WITH A PROJECTED LOW CENTER CROSSING THE NC COAST. ECMWF AND GFS HAS  
LESS THAN 500 CAPE SATURDAY PM. INSTABILITY GENERALLY 1000 TO 1500  
CAPE ARE FORECAST BY THE MODELS EACH PM.  
 
MAX TEMPS WELL INTO THE 80S ON SATURDAY, GRADUALLY COOLING OFF TO  
70S MTNS AND 80 TO 84 FOOTHILLS AND PIEDMONT MON AND TUESDAY DUE TO  
THE INCREASED CLOUDS AND TROPICAL SATURATION. MINS IN THE 60S.  
 

 
   
AVIATION /03Z WEDNESDAY THROUGH SUNDAY/
 
 
AT KCLT AND ELSEWHERE: DAYTIME CUMULUS HAS DISSIPATED, BUT MID LEVEL  
MOISTURE IS INCREASING SLIGHTLY OVER THE MOUNTAINS AHEAD OF A WEAK  
APPROACHING UPPER WAVE. MOST LOCATIONS MAY ALSO SEE AT LEAST FEW TO  
SCT HIGH BASED STRATOCUMULUS OVERNIGHT AS A NARROW MOISTURE ZONE IS  
TRAPPED BENEATH A WEAK INVERSION LAYER. SOME BRIEF FOG IN THE  
SOUTHWEST MOUNTAIN VALLEYS IS POSSIBLE TOWARD SUNRISE, BUT MID AND  
HIGH CLOUDS SHOULD KEEP THE FOG FROM BECOMING DENSE. CUMULUS  
PRODUCTION AND MID LEVEL MOISTURE WILL INCREASE THROUGH WED FROM THE  
WEST. ISOLD TO SCATTERED MOUNTAIN RIDGE TOP SHOWERS ARE EXPECTED  
THROUGH LATE WED, BUT WITH THE CONFIDENCE TOO LOW FOR ANY MENTION AT  
KAVL OR THE OTHER AIRFIELDS. EXPECT GENERALLY LIGHT SW WINDS THROUGH  
THE PERIOD, WITH MAX FLOW 5 TO 10 KT DURING MIXING ON WED AFTERNOON.  
 
OUTLOOK: MAINLY VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD, BUT  
PATCHY MORNING FOG CHANCES CONTINUE AT KAVL. SCATTERED AFTERNOON  
SHRA/TSRA COVERAGE WILL INCREASE THURSDAY THROUGH FRIDAY - WITH MORE  
UNCERTAINTY ON SAT.  
 
CONFIDENCE TABLE...  
 
02-08Z 08-14Z 14-20Z 20-00Z  
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%  
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%  
KAVL HIGH 100% HIGH 100% HIGH 100% HIGH 100%  
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%  
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 SCHEDULE 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...DEO  
NEAR TERM...HG  
SHORT TERM...CDG  
LONG TERM...DEO  
AVIATION...HG  
 
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