901  
FXUS62 KGSP 241106  
AFDGSP  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC  
706 AM EDT SUN MAY 24 2015  
   
SYNOPSIS
 
 
DRY CANADIAN HIGH PRESSURE WILL REMAIN ATOP THE REGION TODAY. THE  
HIGH TAKES ON A SUMMERTIME BERMUDA HIGH PATTERN ON MEMORIAL DAY AND  
REMAINS THERE THROUGH THE WEEK. A MOIST SOUTHERLY FLOW DEVELOPS WITH  
INCREASING CHANCES FOR CONVECTION.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
AS OF 700 AM...FCST IS ON TRACK. I DID REMOVE THE FOG FROM THE MTN  
VLYS...AS NO FOG HAS DEVELOPED. ALSO BUMPED UP SKY COVER SLIGHTLY TO  
ACCOUNT FOR THE INCREASED CIRRUS ON THE IR SAT IMAGERY.  
 
AS OF 230 AM...A LARGE UPPER RIDGE WILL REMAIN OVER THE AREA  
TODAY...WHILE THE CENTER OF THE SFC RIDGE SETS UP OFF THE MID  
ATLANTIC COAST. THE INCREASING SOUTHEASTERLY LLVL FLOW ATOP THE CWFA  
SHUD BEGIN TO TRANSPORT SOME SHALLOW ATLANTIC MOISTURE INTO THE  
AREA. HOWEVER...MID LVL SUBSIDENCE WILL RESULT IN ANOTHER DRY DAY.  
THICKNESSES WILL BE SIMILAR TO YESTERDAY...WITH MAX TEMPS ABOUT A  
CATEGORY ABOVE NORMAL.  
 
TONIGHT...MODELS IN GOOD AGREEMENT ON A SHALLOW MOIST LAYER REACHING  
THE UPPER SAVANNAH VALLEY AND SOUTHERN BLUE RIDGE ESCARPMENT  
OVERNIGHT. SO EXPECT STRATUS TO DEVELOP...AT LEAST ACRS THE WESTERN  
HALF OF THE CWFA BY DAYBREAK MONDAY. MOST OF THE GUIDANCE TRIES TO  
SQUEEZE OUT A FEW LIGHT SHWRS ALONG THE ESCARPMENT WITHIN THE  
SOUTHEASTERLY UPSLOPE FLOW. HOWEVER...FCST SNDGS SHOW THE DEPTH OF  
THE NEAR-SATURATED LAYER TO BE VERY SHALLOW. SO WILL GO WITH A DRY  
FCST OVERNIGHT. TEMPS WILL BE A COUPLE CATEGORIES ABOVE NORMAL  
WITHIN THE SE FLOW AND INCREASING CLOUDS LATE.  
 

 
   
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/
 
 
AS OF 155 AM SUNDAY...THE UPPER RIDGE AXIS OVER THE AREA SLIDES TO  
THE COAST ON MONDAY ALLOWING A SWLY FLOW TO DEVELOP. THIS PATTERN  
HOLDS ON TUE WITH A SERIES OF WEAK SHORT WAVES SLIDING THRU THE FLOW  
AND OVER OR NEAR THE CWFA. AT THE SFC...RIDGING FROM THE BERMUDA  
HIGH WEAKENS ALLOWING A LOW LEVEL SLY TO SWLY FLOW TO DEVELOP AS  
WELL. THIS WILL HELP CREATE A DEEP PLUME OF GULF MOISTURE WHICH  
MOVES INTO THE AREA...ESPECIALLY THE WRN CWFA DURING THIS PERIOD.  
THEREFORE...EXPECT SCT CONVECTION TO DEVELOP OVER THE WRN CWFA  
MONDAY DIMINISHING TO NO CONVECTION OVER THE I-77 CORRIDOR. PRECIP  
CHC INCREASES ACROSS THE BOARD ON TUE AS MOISTURE AND FORCING  
INCREASE. ALTHOUGH THERE WILL BE A DIURNAL TREND TO THE CONVECTIVE  
COVERAGE...EXPECT AT LEAST SOME SHRA TO LINGER THRU THE NITE GIVEN  
THE COPIOUS LOW LEVEL MOISTURE AND GENERAL UPSLOPE FLOW. THE THREAT  
OF SEVERE WEATHER WILL BE MITIGATED BY POOR LAPSE RATES AND  
RELATIVELY WEAK INSTABILITY. ABOVE NORMAL TEMPS MON WILL REMAIN  
NEARLY STEADY OR RISE A COUPLE OF DEGREES TUE DEPENDING ON LOCATION.  
 

 
   
LONG TERM /WEDNESDAY THROUGH SATURDAY/
 
 
AS OF 315 AM SUNDAY...THE UPPER RIDGE AXIS OVER THE EAST COAST  
WEAKENS AND ALLOWS A SERIES OF SHORT WAVES TO MOVE OVER OR NEAR THE  
AREA THRU THE PERIOD. AT THE SFC...A BERMUDA HIGH REMAINS IN PLACE  
OVER THE AREA IN A PATTERN MORE TYPICAL OF SUMMER. THIS KEEPS A  
MOIST SWLY FLOW OVER THE AREA. THIS PATTERN WILL LEAD TO MAINLY  
DIURNAL CONVECTION EACH DAY...POSSIBLY LINGERING THRU THE NITE WED  
NITE. COVERAGE WILL LIKELY BE HIGHER WED AND THU THEN ON FRI AND  
SAT...DUE TO GREATER MOISTURE EARLY IN THE PERIOD. TEMPS WILL REMAIN  
ABOVE NORMAL THRU THE PERIOD.  
 

 
   
AVIATION /11Z SUNDAY THROUGH THURSDAY/
 
 
AT KCLT...NO MAJOR CHANGES TO THE THINKING FOR THE 12Z TAFS. AS HIGH  
PRESSURE SLIDES EAST...SOUTHEASTERLY FLOW WILL INCREASE A BIT TODAY  
COMPARED TO YESTERDAY. WINDS WILL START OUT CALM OR LGT SE...THEN  
INCREASE TO THE 8-12 KT RANGE WITH A FEW LOW-END GUSTS POSSIBLE THIS  
AFTN. THERE WILL BE A FEW WISPS OF THIN CIRRUS THRU THE DAY...WITH A  
FEW FAIR WX CUMULUS WITH BASES AROUND 5000 FT. SOME LLVL MOISTURE  
WILL INCREASE OFF THE ATLANTIC...WITH GUIDANCE SHOWING LOW CIGS  
DEVELOPING TO THE WEST OF KCLT BEFORE DAYBREAK. GUIDANCE IN GOOD  
AGREEMENT THAT IT SHUD REMAIN WEST OF THE TERMINAL THRU 12Z...SO NO  
LOW CIGS WILL BE SHOWN IN THE 12Z TAF.  
 
ELSEWHERE...SE WINDS WILL PICK UP TO THE 8-12 KT RANGE UNDER A FEW  
FAIR WX. A FEW FAIR WX CUMULUS CLOUDS WITH BASES IN THE 4500 TO 6000  
FT RANGE ARE EXPECTED THIS AFTN. MODELS IN GOOD AGREEMENT THAT IFR  
OR LOW MVFR CIGS WILL DEVELOP BEFORE DAYBREAK MONDAY...AS THE  
SOUTHEASTERLY LLVL FLOW TRANSPORTS ATLANTIC MOISTURE INTO THE AREA.  
THE STRATUS MAY OR MAY NOT MAKE IT TO KHKY. SO WILL LEAVE OUT OF THE  
12Z TAF THERE.  
 
OUTLOOK...MOISTURE WILL GRADUALLY RETURN OUT OF THE SOUTH THRU THE  
MIDDLE OF THE WEEK. SO INCREASED MORNING STRATUS...AND A RETURN OF  
ISOLD TO SCATTERED AFTN/EVE SHRA/TSRA CAN BE EXPECTED BY TUESDAY-  
WEDNESDAY.  
 
CONFIDENCE TABLE...  
 
11-17Z 17-23Z 23-05Z 05-06Z  
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 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...RWH  
NEAR TERM...ARK  
SHORT TERM...RWH  
LONG TERM...RWH  
AVIATION...ARK  
 
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