Area Forecast Discussion
Issued by NWS Greer, SC

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS62 KGSP 260750 AFDGSP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 350 AM EDT SUN APR 26 2015 .SYNOPSIS... AN AREA OF LOW PRESSURE WILL MOVE OFF THE CAROLINA COAST THIS MORNING...WITH A TRAILING COLD FRONT PUSHING THROUGH THE FORECAST AREA. COOL AND DRY HIGH PRESSURE DROPS DOWN FROM CENTRAL CANADA LATER TODAY AND WILL REMAIN THE DOMINANT FEATURE FOR THE BEGINNING OF THE WORK WEEK. ANOTHER AREA OF LOW PRESSURE WILL MOVE EAST FROM TEXAS TOWARD THE MIDDLE OF THE WEEK AND BRING MORE RAIN WEDNESDAY AND THURSDAY...WITH A DRYING TREND FOR THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 330 AM...SATELLITE AND RADAR IMAGES CONTINUES TO SHOW THE OLD MCS ASHING OUT ACROSS THE WESTERN CAROLINAS. LATEST RUN OF THE CAMS INDICATE THE COVERAGE WILL SPREAD EAST...GRADUALLY FADING TO CHC TO SCHC. IS WAS INTERESTING TO SEE A SPLITTING CELL ACROSS CHESTERFIELD CO AT 730Z. AT THE SFC...THE WEDGE FRONT RUNS FROM THE NORTHERN TIP OF LAKE WATEREE...WEST ACROSS THE GSP METRO AREA...NORTH ALONG THE EAST FACING SLOPES ACROSS THE NC FOOTHILLS. NORTH OF THE BOUNDARY...LOW CLOUDS AND FOG WILL PERSIST THROUGH SUNRISE. LOW CLOUDS AND FOG WILL DISSIPATE FROM THE SOUTH TO NORTH DURING THE EARLY DAYLIGHT HOURS. BY MID DAY...THE CENTER OF LOW PRESSURE IS EXPECTED TO PASS ACROSS THE UPSTATE OF SC...TRACKING EAST. A WEAK BACKDOOR COLD FRONT WILL SWEEP SOUTH ACROSS THE REGION DURING THE AFTERNOON. AS THE LOW PASSES...THE ENVIRONMENT BETWEEN I-85 TO I-77 COULD SUPPORT SCT TSRA DURING THE MID TO LATE AFTERNOON...I WILL FORECAST CHC POPS. HIGH TEMPERATURES ARE FORECAST TO RANGE FROM AROUND 80 ACROSS THE UPPER SAVANNAH RIVER VALLEY TO THE MID 60S ACROSS I-40 TO THE MTNS. TONIGHT...IN THE WAKE OF THE COLD FRONT...HIGH PRESSURE WILL BUILD ACROSS THE SOUTHERN APPALACHIAN REGION. CONDITIONS ACROSS THE REGION SHOULD BECOME CLEAR TO MOSTLY CLEAR...WINDS BELOW 5 KTS...WITH DEWPOINT DEPRESSION GREATER THAN 5 DEGREES. LOW TEMPERATURES SHOULD FALL CLOSE TO NORMAL...FROM THE LOW 40S WITHIN THE MTN VALLEYS TO LOW 50S ACROSS THE UPPER SAVANNAH RIVER VALLEY. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 300 AM SUNDAY...SHORT TERM BEGINS WITH LARGE UPPER CLOSED LOW SPINNING OVER NEW ENGLAND AND SOUTHEAST CANADA...WITH A REINFORCING SHORTWAVE PUSHING AROUND THE WESTERN PERIPHERY OF THE TROUGH AT THE BEGINNING OF THE PERIOD. SURFACE HIGH PRESSURE CENTERED OVER SOUTH CENTRAL CANADA WILL BE RIDGING INTO THE SOUTHEAST. EXPECT A CLEARING TREND DURING THE DAY ON MONDAY IN THE WAKE OF THE DRY UPPER TROUGH AXIS PUSHING THROUGH WITH HIGHS BELOW NORMAL UNDER WEAK DEEP LAYER CAA. CONTINUED BELOW-NORMAL TEMPERATURES MONDAY NIGHT AND WILL HAVE TO KEEP AN EYE ON LOWS AT THE HIGHER ELEVATIONS IN CASE FROST MIGHT BE A CONCERN...ESPECIALLY AS WINDS DIE OFF TOWARD SUNRISE TUESDAY. THE COOL TEMPERATURES CONTINUE ON TUESDAY EVEN WITH MIDLEVEL RIDGING BEGINNING TO BUILD IN ACROSS THE AREA. A CUTOFF LOW OVER THE SOUTHERN PLAINS WILL INDUCE CYCLOGENESIS ACROSS THE NORTHERN GULF MONDAY NIGHT AND EARLY TUESDAY...SPREADING MOISTURE INTO THE SOUTHEAST TUESDAY AFTERNOON AND EVENING. HAVE CONTINUED TREND OF RAMPING UP POPS LATE IN THE DAY ON TUESDAY AS ISENTROPIC UPGLIDE INCREASES ACROSS THE AREA. ECMWF IS BEGINNING TO TREND A LITTLE FARTHER NORTH WITH THE SURFACE LOW...MORE INTO SOUTHERN AND EVEN CENTRAL GEORGIA RATHER THAN REMAINING ALONG THE FLORIDA PANHANDLE...WHICH MIGHT MEAN AN INCREASE IN QPF. OVERALL MASS FIELDS NOT TOO DISSIMILAR BUT ENOUGH DIFFERENCES IN THE DETAILS...ESPECIALLY TIMING AND PLACEMENT OF QPF...TO CONTINUE BLANKETING THE AREA WITH HIGH CHANCE TO LOW LIKELY POPS AT BEST AS WE TRANSITION INTO THE EXTENDED. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 315 AM SUNDAY...CHANCE TO LIKELY POPS /ESPECIALLY FOR SOUTHERN ZONES/ BEGIN THE PERIOD AS THE AFOREMENTIONED SURFACE LOW WORKS ITS WAY EAST ACROSS SOUTHERN GEORGIA. WITH WIDESPREAD CLOUDINESS AND RAIN...NOT TO MENTION DECREASING THICKNESSES PLUS JUST BEING ON THE COLD SIDE OF THE SURFACE LOW...WE CONTINUE TO ADVERTISE HIGHS ON WEDNESDAY WELL BELOW SEASONAL NORMALS...IN SOME LOCATIONS 10 DEGREES OR SO. MODEL INCONSISTENCIES AND RUN-TO-RUN DISCONTINUITY CONTINUE WITH THIS SYSTEM AS THE 00Z GUIDANCE HAS ONCE AGAIN SWITCHED...WITH THE GFS EXITING THE PRECIP FROM THE AREA FASTER THAN THE ECMWF. CONTINUED THE COMPROMISE TREND...PULLING BACK ON POPS DURING THE DAY ON THURSDAY. ECMWF WANTS TO BRING ANOTHER SHORTWAVE AROUND THE BASE OF THE ELONGATED TROUGH THURSDAY NIGHT INTO FRIDAY BUT HAVE NOT REFLECTED THIS IN THE GRIDS AT THIS TIME...PREFERRING INSTEAD THE DRIER SOLUTIONS...HOWEVER AS WE MOVE FORWARD THIS MAY NEED TO BE REEVALUATED. WE SHOULD SEE A DRYING TREND INTO THE WEEKEND WITH TEMPERATURES TRENDING MORE TOWARDS CLIMATOLOGY BUT CONFIDENCE IN ANY ONE SOLUTION NOT PARTICULARLY HIGH AT THIS POINT. && .AVIATION /08Z SUNDAY THROUGH THURSDAY/... AT KCLT AND ELSEWHERE...LATEST SFC ANALYSIS AND SATELLITE IMAGES INDICATED THAT THE WEDGE BOUNDARY WAS CURVED FROM THE NORTHERN TIP OF LAKE WATEREE...ACROSS THE GSP METRO...THEN NORTH ALONG THE EAST FACING SLOPES ACROSS THE NC FOOTHILLS. AREAS NORTH OF THE BOUNDARY WERE OBSERVING LIFR CEILINGS WITH POCKETS OF LIFR VIS. HOWEVER...A WEAKENING MCS WILL LIKELY TRACK ACROSS THE MTNS...GENERALLY EAST BY 8Z. THE PASSAGE OF THE DECAYING CONVECTION MAY MIX OUT THE LLVL CEILINGS AND VIS...BUT EXPECT THE RESTRICTIONS TO REDEVELOP. KCLT...KHKY...KGSP...AND KGMU ARE EXPECTED TO REMAIN WITHIN THE CORRIDOR OF LOW CEILINGS AND VIS THROUGH SUNRISE...THEN CONDITIONS SHOULD IMPROVE TO MVFR BY MID MORNING...THEN VFR BY MID DAY. KAVL AND KAND WILL REMAIN REMOVED FROM THE WEDGED AIR MASS...COMBINED WITH WINDS ABOVE 5 KTS...CONDITIONS ARE GENERALLY EXPECTED TO REMAIN MVFR OR HIGHER THIS MORNING. THE REST OF THE DAY SHOULD FEATURE BKN LOW TO MID CLOUDS...THICKER AND MORE PERSISTENT ACROSS KHKY AND KCLT. FURTHER SOUTH...KAND SHOULD SEE GUSTY WEST WINDS THROUGH THE DAYLIGHT HOURS. ALL TERMINALS SHOULD SEE WINDS TURN FROM THE NORTH LATE THIS AFTERNOON AND EARLY EVENING FOLLOWING A COLD FRONT. OUTLOOK...A COLD FRONT WILL SWEEP ACROSS THE REGION ON SUNDAY THEN FOLLOWED BY DRY HIGH PRESSURE THROUGH TUESDAY. ANOTHER LOW PRESSURE SYSTEM MAY TRACK ACROSS THE DEEP SOUTH WEDNESDAY AND THURSDAY. CONFIDENCE TABLE... 07-13Z 13-19Z 19-01Z 01-06Z KCLT MED 72% HIGH 84% HIGH 97% MED 64% KGSP MED 78% HIGH 96% HIGH 100% HIGH 100% KAVL HIGH 90% HIGH 97% HIGH 95% MED 78% KHKY MED 67% HIGH 82% HIGH 90% HIGH 100% KGMU MED 78% HIGH 96% HIGH 100% HIGH 100% KAND MED 79% HIGH 100% HIGH 91% 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...TDP NEAR TERM...NED SHORT TERM...TDP LONG TERM...TDP AVIATION...NED

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.