Area Forecast Discussion
Issued by NWS Greer, SC

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485 FXUS62 KGSP 052336 AFDGSP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 636 PM EST FRI FEB 5 2016 .SYNOPSIS... AN UPPER LEVEL RIDGE AND DRY SURFACE HIGH PRESSURE WILL SLOWLY CROSS THE FORECAST AREA THROUGHOUT THE WEEKEND. A COLD FRONT WILL PUSH THROUGH THE REGION ON MONDAY...USHERING IN BELOW NORMAL TEMPERATURES AND AN INCREASE OF MOISTURE INTO THE MIDDLE OF NEXT WEEK. && .NEAR TERM /THROUGH SATURDAY/... AS OF 630 PM EST...WINDS CONTINUE TO RELAX AS SURFACE HIGH PRESSURE BUILDS EAST ACROSS THE REGION THIS EVENING. UPSTREAM...WATER VAPOR IMAGERY SHOWS A DIGGING TROUGH ACROSS THE PLAINS/RED RIVER VALLEY REGION AND SOME THIN HIGH CLOUDS WILL SPILL EAST OF THIS SYSTEM AND MOVE OVER THE REGION OVERNIGHT. THE CIRRUS WILL NOT GREATLY IMPEDE RADIATIONAL COOLING AND MINS ABOUT 5 DEGREES BELOW CLIMO ARE STILL EXPECTED. ON SATURDAY...THE UPSTREAM SYSTEM WILL APPROACH FROM THE WEST IN THE MORNING AND REACH AT LEAST THE WESTERN HALF OF THE FORECAST AREA BY THE END OF THE DAY. ALTHOUGH MID/UPPER FORCING LOOK MORE THAN SUFFICIENT FOR PRECIPITATION...OUR SOURCES OF MOISTURE ARE COMPLETELY CUT OFF AND UNAVAILABLE. THUS...EXPECT IT TO REMAIN DRY THIS FAR INLAND WITH JUST INCREASING AND THICKENING MID AND HIGH CLOUDS THROUGH LATE DAY. LINGERING COOL THICKNESSES AND THE INCREASING HIGH CLOUDS WILL KEEP MAX TEMPS BELOW NORMAL AGAIN. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... AS OF 235 PM FRI...VERY INTERESTING WEATHER EXPECTED OFF THE CAROLINA COAST ON SUNDAY. SHORT RANGE MODELS INDICATE THAT A CLOSED H5 LOW WILL TRACK ACROSS THE DEEP SOUTH SUNDAY MORNING. AT H3...THE CORE OF A 135 KTS JET WILL LIFT ALONG THE ATLANTIC COAST OF THE CAROLINAS SUNDAY MORNING. SHORT RANGE MODELS INDICATE THAT SFC LOW PRESSURE WILL RAPIDLY ORGANIZE AND DEEPEN OFF THE SC COAST BETWEEN 0Z TO 12Z SUNDAY. BY 0Z MONDAY...THE 12Z GFS INDICATES H7 OMEGA INCREASING TO OVER 150 UBAR/S ON THE WEST SIDE OF THE SFC LOW CENTER. SIMPLY PUT...THIS ENVIROMENT IS EXPECTED TO RESULT IN EXPLOSIVE OR BOMB CYCLOGENESIS ON SUNDAY. THE 12Z NAM IS THE MOST REACTIVE WITH CENTRAL PRESSURE FALLING FROM 1017 MB AT 0Z SUN TO 984 MB AT 21Z SUN. HOWEVER...THE 12Z GFS AND ECMWF INDICATE A VERY SIMILAR RATE OF PRESSURE FALLS. THIS WOULD MEET OR EXCEED THE PRESSURE FALL RATE TO QUALIFY AS A BOMB CYCLONE. FORTUNATELY...SHORT RANGE GUIDANCE KEEPS THE DEEP MOISTURE AND PRECIP ASSOCIATED WITH THE SYSTEM EAST OF THE FORECAST AREA. HOWEVER...BY MID SUNDAY AFTERNOON THE PRESSURE GRADIENT MAY RANGE TO 5 MBS...SUPPORTING GUSTY NORTHWEST WINDS ACROSS THE REGION. THE GRADIENT WILL DECREASE QUICKLY SUNDAY EVENING AS THE COASTAL LOW RACES OFF TO THE NORTHEAST. HIGH TEMPERATURES ARE FORECAST TO RANGE FROM THE 40S ACROSS THE MTNS TO LOW TO MID 50S EAST. MONDAY...A COLD FRONT ASSOCIATED WITH ANOTHER LOW OVER THE GREAT LAKES WILL SWEEP OVER THE SOUTHERN APPALACHIANS BY SUNRISE. PRECIP SHOULD BEGIN AS SNOW ACROSS THE MTNS...GIVEN LOW TEMPS IN THE LOW 30S. HOWEVER...AFTER SUNRISE...TEMPS WILL SLOWLY WARM...CHANGING PRECIP TO RAIN. BY THE AFTERNOON...TEMPS ARE FORECAST TO RANGE FROM THE LOW 40S WITHIN THE VALLEY FLOOR TO NEAR 50 EAST. PRECIP WILL GENERALLY FALL AS LIQUID RAIN. HOWEVER...ELEVATION ABOVE 3500 FEET MAY REMAIN AS SNOW THROUGH THE AFTERNOON HOURS. BY THE END OF DAYLIGHT MONDAY...SEVERAL HIGH MTN PEAKS NEAR THE TN LINE MAY SEE A COUPLE OF INCHES OF SNOWFALL. WE WILL CONTINUE TO HIGHLIGHT IN THE HWO. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... AS OF 215 PM FRIDAY...THE MEDIUM RANGE WILL START OUT MONDAY EVENING WITH A LARGE UPPER LEVEL VORTEX/TROF OVER THE SOUTHERN GREAT LAKES AND OH VALLEY...WITH SPOKES OF VORTICITY PIVOTING AROUND THE CIRCULATION. ONE OF THOSE SPOKES/VORT LOBES WILL CROSS THE CWFA ON TUESDAY...PRODUCING ANOTHER ROUND OF MODEST MID TO UPPER LEVEL QG FORCING. HOWEVER...IT DOES NOT LOOK AS IMPRESSIVE...AND MID LEVEL LAPSE RATES WILL NOT BE AS STEEP AS ON MONDAY. STILL...MOISTURE AND LIFT ALONG WITH INCREASINGLY BETTER NW UPSLOPE FLOW SHOULD KEEP SCATTERED TO NUMEROUS SNOW SHOWERS ALONG THE TN BORDER. AS FOR PRECIP FROM THE BLUE RIDGE AND EAST...MODELS HAVE BACKED OFF ON PRECIP /BREAKING CONTAINMENT/...SO I WILL ONLY FORECAST A SLIGHT CHANCE OF RAIN AND SNOW SHOWERS ACROSS THE NC FOOTHILLS AND NW PIEDMONT. TEMPS WILL BE ABOUT 10-15 DEGREES BELOW NORMAL UNDER THE TROF. TUESDAY NIGHT AND BEYOND...THE AXIS OF THE UPPER TROF WILL SWING EAST OF THE AREA...BUT A LARGE MILLER-B LIKE LOW WILL BE ONGOING ACROSS THE GREAT LAKES AND THE NORTHEAST. SO A PROLONGED MOIST NW FLOW WILL CONTINUE ALONG THE TN/NC BORDER...BEFORE TAPERING OFF WEDNESDAY NIGHT. THE 850 MB TEMPS WILL BOTTOM OUT WEDNESDAY INTO WEDNESDAY NIGHT...RESULTING IN TEMPS 15-20 DEGREES BELOW NORMAL AND POTENTIALLY WIND CHILL ADVISORY CONDITIONS IN THE HIGH TERRAIN. TEMPS START TO REBOUND THURSDAY AND FRIDAY...AS THE EASTERN TROF STARTS TO FLATTEN OUT. ANOTHER REINFORCING TROF OR WEAK CLIPPER SYSTEM WILL DIVE INTO THE GREAT LAKES AND OH VALLEY EARLY FRIDAY. THIS MAY BRING A BRIEF SHOT OF MOISTURE AND NW FLOW SNOW SHOWER ACTIVITY. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... AT KCLT AND ELSEWHERE...VFR CONDITIONS WILL CONTINUE THROUGH THE PERIOD. EXPECT MOSTLY CLEAR SKIES THROUGH DAYBREAK SATURDAY...BUT WITH GRADUALLY INCREASING HIGH CLOUDS THROUGH THE DAY ON SATURDAY AS A POTENT UPPER LOW APPROACHES FROM THE WEST. WINDS WILL CONTINUE TO DIMINISH...WITH MAINLY LIGHT N TO NE FLOW EAST OF THE MOUNTAINS AND CONTINUED NW WINDS LESS THAN 10 KT AT KAVL. OUTLOOK...WEAK HIGH PRESSURE WILL REMAIN ACROSS THE REGION THROUGH THE WEEKEND. A STRONG UPPER AIR DISTURBANCE COULD BRING ENOUGH MOISTURE TO WRING OUT A FEW RAIN OR SNOW SHOWERS ON MONDAY. CONFIDENCE TABLE... 23-05Z 05-11Z 11-17Z 17-18Z 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. 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...SBK NEAR TERM...HG/PM SHORT TERM...NED LONG TERM...ARK AVIATION...HG/PM

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