Area Forecast Discussion
Issued by NWS Greer, SC

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000 FXUS62 KGSP 231034 AFDGSP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 634 AM EDT SAT MAY 23 2015 .SYNOPSIS... DRY CANADIAN HIGH PRESSURE WILL LINGER ATOP THE REGION THROUGH THE HOLIDAY WEEKEND. A SOUTHERLY FLOW OF MOISTURE AROUND BERMUDA HIGH PRESSURE WILL GRADUALLY RETURN NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 630 AM...FCST IS ON TRACK...SO NO CHANGES NEEDED WITH THIS UPDATE. AS OF 230 AM...AN UPPER RIDGE WILL CONTINUE TO BUILD ALONG A NEGATIVELY-TILTED AXIS FROM FL TO TO MN. THE HEIGHT RISES ATOP THE CWFA WILL HELP KEEP THINGS DRY WITH SUNNY TO MOSTLY SUNNY SKIES. THE CENTER OF SFC HIGH PRESSURE WILL SHIFT FROM THE CENTRAL APPALACHIANS THIS MORNING...TO JUST OFF THE MID ATLANTIC COAST TONIGHT. SO WITH FLOW TURNING OUT OF THE SOUTHEAST...TEMPS WILL BE A CATEGORY OR TWO WARMER TODAY THAN YESTERDAY...STILL ABOUT A CATEGORY BELOW NORMAL FOR MOST LOCATIONS. LOWS TONIGHT UNDER MOSTLY CLEAR SKIES WILL BE NEAR NORMAL. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 150 AM SATURDAY...DRY WX WILL CONTINUE ON SUNDAY AS UPPER RIDGE AXIS CONTINUES TO BUILD ATOP THE SE CONUS. LLVL FLOW AROUND BERMUDA HIPRES WILL STEADILY ADVECT HIGHER TEMPERATURES AND DWPTS INTO THE SOUTHERN APPALACHIANS. TEMPS WILL BE A FEW DEGREES WARMER THAN SATURDAY TOPPING OUT A FEW DEGREES ABOVE NORMAL. THE UPPER PATTERN EVOLVES SLOWLY ON MONDAY WITH THE RIDGE AXIS SHARPENING AND MOVING EAST CLOSER TO THE COAST. THIS COMBINED WITH A STEADY INCREASE IN LOW LEVEL MOISTURE DUE TO THE INCREASING SLY FLOW AROUND THE WEAKENING RIDGE AXIS OF THE SFC BERMUDA HIGH WILL CREATE INCREASING INSTABILITY AND CHC OF MAINLY DIURNAL CONVECTION. BEST CHC WILL BE ACROSS THE NC MTNS...NE GA AND UPSTATE WEST OF I-26...WITH LITTLE TO NO CHC OVER THE I-77 CORRIDOR WHERE THE SUPPRESSIVE EFFECTS OF THE RIDGE CONTINUE. HIGHS MON REMAIN NEARLY STEADY WEST AND RISE A COUPLE OF DEGREES EAST. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 255 AM SAT...THE MEDIUM RANGE CONTINUES TO LOOK SUMMER-LIKE WITH AN UPPER RIDGE AXIS ALONG THE ATLANTIC COAST AND A SFC BERMUDA HIGH ACROSS THE SE KEEPING A GENERALLY MOIST FLOW FROM THE GULF AND ATLANTIC AT LOW LEVELS ACROSS THE CWFA. THIS WILL FAVOR ABOVE NORMAL TEMPS AND MAINLY DIURNAL SHOWERS AND STORMS EACH DAY. THE GFS CONTINUES TO FORECAST THE RIDGE BREAKING DOWN LATE IN THE PERIOD ALLOWING SHORT WAVE ENERGY AND A WEAK COLD FRONT TO MOVE INTO THE AREA. THE ECMWF CONTINUES TO FORECAST THE UPPER RIDGE/BERMUDA HIGH PATTERN RIGHT THRU THE FORECAST PERIOD. GIVEN THE DISCREPANCY...HAVE TRENDED TOWARD THE MORE STEADY ECMWF FCST. CONVECTIVE COVERAGE WILL BE HIGHER ACROSS THE MTNS AND WRN CWFA EACH DAY WHERE BETTER MOISTURE AND INSTABILITY REMAIN FARTHER FROM THE UPPER RIDGE AXIS. THE CHANCES FOR SEVERE THUNDERSTORMS EACH DAY LOOK MINIMAL AT THIS POINT BECAUSE OF POOR LAPSE RATES AND RELATIVELY WEAK INSTABILITY WITH MID LEVEL WARM AIR. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... AT KCLT AND ELSEWHERE...NO MAJOR CHANGES FOR THE 12Z TAFS. THE CENTER OF DRY HIGH PRESSURE WILL SHIFT FROM THE APPALACHIANS TO THE EAST COAST TODAY...KEEPING DRY AIR IN PLACE...BUT SHIFTING THE WINDS FROM NE TO SE BY THIS AFTN. WINDS SHUD REMAIN LIGHT...PICKING UP TO AROUND 5-7 KT THIS AFTN. OTHER THAN A FEW PERIODS OF CIRRUS...NOT EXPECTING ANY OTHER CLOUDS OR FOG AT ANY OF THE TAF SITES THRU TONIGHT. OUTLOOK...HIGH PRESSURE WILL SHIFT EAST OFF THE EAST COAST EARLY NEXT WEEK...ALLOWING MOISTURE TO GRADUALLY RETURN OUT OF THE SOUTH. CONDITIONS SHOULD REMAIN GENERALLY FAIR THROUGH THE PERIOD. 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 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...CSH NEAR TERM...ARK SHORT TERM...RWH LONG TERM...RWH AVIATION...ARK

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