233  
FXUS62 KGSP 061027  
AFDGSP  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC  
627 AM EDT FRI MAY 6 2016  
   
SYNOPSIS
 
 
THE WEATHER WILL REMAIN UNSETTLED TODAY AS A DEEP UPPER LOW CENTER  
MOVES AWAY TO THE NORTHEAST. ANOTHER FRONT IS EXPECTED TO STALL JUST  
TO OUR NORTH ON SATURDAY AND SUNDAY. THE FRONT SHOULD LIFT BACK TO  
THE NORTH ON MONDAY...AS HIGH PRESSURE OFF THE SOUTHEAST COAST  
EXPANDS AND WARM SOUTHERLY FLOW RETURNS.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
AS OF 630 AM EDT...MOISTURE WITH THE UPPER LOW HAS BECOME  
INCREASINGLY ANEMIC...WITH TEMPERATURES WARMING...MT. MITCHELL IS  
NOW THE COLDEST AT 32F. BEECH WEBCAM STILL SHOWS SOME SNOW ON GRASSY  
AREAS BUT ROADS LOOK CLEAR...REALLY MORE OF A FOG CONCERN WITH THE  
CLOUDS OVER THE MOUNTAINTOPS. WITH THIS...HAVE OPTED TO CANCEL THE  
ADVISORY EARLY. HAVE MADE SOME SIGNIFICANT REDUCTIONS TO POPS THIS  
MORNING TO ACCOUNT FOR TRENDS BUT DID RAMP BACK UP SLIGHTLY THIS  
AFTERNOON AS WE SHOULD GET SOME CONVECTIVE SHOWERS AS LAPSE RATES  
STEEPEN WITH SURFACE WARMING. OTHER CHANGES ARE FOR AVIATION  
PURPOSES WHICH RESULT IN LITTLE TO NO IMPACT TO THE PUBLIC FORECASTS.  
 
OTHERWISE...NEAR TERM WILL BE DOMINATED BY THE SLOWLY LIFTING AND  
FILLING CUT OFF UPPER LOW CURRENTLY OVER VA. FOR NOW THE UPPER LOW  
IS ELONGATED STRETCHING MORE NORTH-SOUTH THAN EAST-WEST BUT AS THE  
SHORTWAVE AXIS ROUNDS THE BASE...THE LOW WILL LIFT TOWARD PA/NC  
TODAY. ANOTHER SHORTWAVE WILL ROUND THE BASE TONIGHT...AND BY THE  
END OF THE PERIOD THE UPPER TROUGH AXIS WILL BE GENERALLY OFF THE  
CAROLINA COAST WITH NEGATIVE VORTICITY ADVECTION DEVELOPING OVER THE  
FORECAST AREA.  
 
SHOULD SEE ANOTHER ROUND OF BELOW-NORMAL HIGHS TODAY WITH THE CAA  
REGIME IN PLACE. LAPSE RATES WILL REMAIN PRETTY STEEP BUT WITH THE  
SLOW NORTH/NORTHEASTWARD MOVEMENT OF THE LOW...WE START LOSING UPPER  
DIFFLUENCE. THE SYSTEM BECOMES MORE MOISTURE-STARVED AS WELL WITH  
QUITE A BIT OF DRYING ALOFT BY MIDDAY. HAVE LEFT SLIGHT CHANCE POPS  
ACROSS EASTERN ZONES AND ALSO ACROSS THE MOUNTAINS BUT OTHERWISE  
HAVE REDUCED POP TRENDS A LITTLE MORE QUICKLY. CANNOT TOTALLY RULE  
OUT THUNDER CHANCES ESPECIALLY WITH THE STEEP LAPSE RATES  
CONTRIBUTING TO VERY LOW CAPE VALUES /LIKE LESS THAN 200 J/KG/ ABOVE  
A DEEPLY MIXED SURFACE LAYER...AND LIKE YESTERDAY SOME TEENY TINY  
HAIL IS MOST CERTAINLY POSSIBLE. BIGGER CONCERN...AT LEAST AS FAR AS  
SENSIBLE WEATHER GOES...WILL BE THE CONTINUED LOW-END WIND  
GUSTS...WELL BELOW ADVISORY CRITERIA BUT COMBINED WITH THE  
BELOW-NORMAL TEMPERATURES MIGHT CONTINUE TO MAKE IT FEEL A LITTLE  
COOL OUT THERE. SHOULD SEE A CLEARING TREND LATE IN THE PERIOD WITH  
LOWS TONIGHT CREEPING BACK UP TO NEAR NORMAL TEMPERATURES.  
 

 
   
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/
 
 
AS OF 255 AM FRIDAY...THE ISSUE FOR THE WEEKEND IS HOW FAR TO THE  
SOUTH A BACK DOOR COLD FRONT MAKES IT BEFORE STALLING...AND HOW MUCH  
PRECIP ACTIVITY WILL DEVELOP ALONG THE BOUNDARY. BEFORE WE GET  
THERE...SOME PRECIP COULD DEVELOP ALONG THE TN BORDER ON SATURDAY AS  
A WEAK UPPER WAVE DROPS DOWN FROM THE NW. THIS WILL BE HANDLED WITH  
A SLIGHT CHANCE...WHICH TAPERS OFF IN THE LATE AFTERNOON AFTER THE  
WAVE AND DEEPER MOISTURE PASS. THE OPERATIONAL MODEL GUIDANCE IS IN  
FAIRLY GOOD AGREEMENT WITH DROPPING THE BACK DOOR BOUNDARY ONLY AS  
FAR SOUTH AS THE VA/NC BORDER ON SUNDAY. THE DIFFERENCE IS IN THE  
DETAILS...WHERE THE GFS AND SREF DEVELOP MORE PRECIP SOUTH OF THE  
BOUNDARY SUNDAY AND SUNDAY NIGHT. THE FCST FOLLOWS MORE IN LINE WITH  
THE NAM/ECMWF IN KEEPING THE BETTER PRECIP CHANCES TO OUR N WITH  
ONLY A TOKEN SLIGHT CHANCE/CHANCE ON THE N AND NW FRINGE OF THE FCST  
AREA. UNLESS THERE IS MORE UPPER FORCING THAN INDICATED...PRECIP  
SEEMS UNLIKELY E OF THE BLUE RIDGE ACROSS NORTHEAST GA AND UPSTATE  
SC BECAUSE OF DOWNSLOPE DRYING. FURTHERMORE...THE UPPER RIDGE WILL  
BUILD IN FROM THE WEST DURING THE DAY WHICH SHOULD MAKE THE  
SITUATION LESS FAVORABLE FOR PRECIP WITH TIME. TEMPS WILL REBOUND TO  
NEAR NORMAL ON SATURDAY...THEN GUIDANCE HAS HIGH TEMPS CLIMBING 5-10  
DEG ABOVE NORMAL FOR SUNDAY. CONFIDENCE IS NOT GREAT THAT WE WILL  
WARM UP THAT QUICKLY...BUT THE WARMUP IS GENERALLY IN LINE WITH THE  
WESTERLY DOWNSLOPE BY SUNDAY AFTERNOON.  
 

 
   
LONG TERM /MONDAY THROUGH THURSDAY/
 
 
AS OF 330 AM FRIDAY...NEXT WEEK LOOKS LIKE A RETURN TO SOMETHING  
MORE TYPICAL OF LATE SPRING WITH TEMPS ABOVE NORMAL AND DIURNALLY  
DRIVEN CONVECTIVE PRECIP. MONDAY LOOKS LIKE THE DAY WITH THE  
SMALLEST CHANCE FOR SHOWERS AS A FLAT UPPER RIDGE MOVES ACROSS THE  
REGION AND WE LACK ANY MEANINGFUL MID/UPPER FORCING. AFTER MONDAY  
THOUGH...WE END UP WITH WHAT AMOUNTS TO A NEARLY ZONAL UPPER FLOW  
ACROSS MOST OF THE SOUTH. HIGH PRESSURE OVER THE WESTERN ATLANTIC  
WILL ALLOW FOR MOISTURE TO RETURN FROM THE GULF THROUGH MID-WEEK...  
WHICH SHOULD PROVIDE THE FUEL FOR DIURNAL PRECIP DEVELOPMENT. THE  
MAIN PROBLEM WILL BE THE TIMING OF ANY WEAK SHORT WAVES CAUGHT UP IN  
THE ZONAL FLOW THAT WOULD MOVE THROUGH AND ENHANCE PRECIP CHANCES.  
THE GFS HAS ONE MOVING THRU WEDNESDAY AND ANOTHER LATE THURSDAY...  
WITH SOME SHORT WAVE RIDGING IN BETWEEN. THE ECMWF REMAINS A BIT  
MORE SUBDUED IN THAT REGARD. THE PATTERN FAVORS A PRECIP CHANCE  
CLOSE TO CLIMATOLOGY FOR LATE SPRING...MEANING A CHANCE OF SHOWERS  
AND STORMS MAINLY IN THE AFTERNOON AND EVENING OVER THE MOUNTAINS  
AND FOOTHILLS...AND A SLIGHT CHANCE OVER THE PIEDMONT. OVERALL...  
FEW CHANGES WERE MADE TO THE ONGOING FORECAST. MAINLY...TEMPS WERE  
RAISED A BIT LATE IN THE PERIOD.  
 

 
   
AVIATION /12Z FRIDAY THROUGH TUESDAY/
 
 
AT KCLT AND ELSEWHERE...STILL ISOLATED -SHRA ACROSS THE AREA AS THE  
UPPER LOW BEINGS TO LIFT OUT. COULD SEE A RESURGENCE IN -SHRA THIS  
AFTERNOON AS LAPSE RATES INCREASE DUE TO SURFACE HEATING...BUT FOR  
NOW NOT ENOUGH TO INCLUDE PROB30 JUST YET. SHOULD SEE SCT-BKN  
MIDLEVEL CLOUDS...6-9KFT...ACROSS THE AREA INTO THIS AFTERNOON BUT  
CLEARING SKIES THEREAFTER. N/NNW WINDS THROUGH THE PERIOD AND GUSTY  
THIS AFTERNOON WITH INCREASING DEEP MIXING...GENERALLY GUSTS  
20-30KT. GUSTS WILL SUBSIDE AFTER SUNSET.  
 
OUTLOOK...DRYING WILL CONTINUE INTO SATURDAY. A COLD FRONT WILL  
APPROACH FROM THE NORTH SUNDAY...WITH ASSOCIATED PRECIPITATION  
POSSIBLY APPROACHING KAVL TO KHKY BEFORE THE FRONT STALLS. WARMING  
CONDITIONS WITH A RETURN TO SW FLOW ARE EXPECTED THROUGH EARLY NEXT  
WEEK.  
 
CONFIDENCE TABLE...  
 
10-16Z 16-22Z 22-04Z 04-06Z  
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%  
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%  
KAVL HIGH 94% 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. COMPLET 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...PM  
NEAR TERM...TDP  
SHORT TERM...PM  
LONG TERM...PM  
AVIATION...TDP  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab SC Page
The Nexlab NC Page
The Nexlab GA Page Main Text Page