188
FXUS62 KGSP 130547
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1247 AM EST WED NOV 13 2024
SYNOPSIS
DRY HIGH PRESSURE REMAINS IN PLACE TODAY. CLOUDS AND PRECIPITATION
ARRIVING LATE TONIGHT WILL MAKE FOR A VERY DAMP AND CHILLY THURSDAY.
DRY WEATHER A WARMING TREND EXPECTED FRIDAY THROUGH THE WEEKEND. DRY
AND WARM CONDITIONS WILL LINGER INTO EARLY NEXT WEEK.
NEAR TERM /THROUGH TODAY/
AS OF 1240 AM EST WEDNESDAY: NO MAJOR CHANGES WERE NEEDED AS THE
FORECAST REMAINS ON TRACK. A FEW CIRRUS ARE TRACKING ACROSS THE
NORTHERN HALF OF THE FORECAST AREA WHILE DRY CONDITIONS PERSIST.
OTHERWISE, HIGH PRESSURE WILL REMAIN CENTERED OVER QUEBEC THIS
MORNING, SUPPORTED BY A SLOW-MOVING FULL-LATITUDE MID/UPPER RIDGE,
THE AXIS OF WHICH WILL APPROACH OUR AREA FROM THE WEST AND MOVE
OVERHEAD LATER TODAY. THE AIR MASS BUILDING DOWN FROM THE HIGH TO
THE NORTH THIS MORNING WILL BE MUCH COOLER AND DRIER THAN WHAT WE
HAVE OBSERVED LATELY. GUIDANCE FINALLY SHOWS LOW TEMPS DROPPING DOWN
CLOSE TO SEASONAL NORMS. THIS COULD BRING SOME FREEZING TEMPS TO THE
MOUNTAINS AND SOME FROST POTENTIAL TO THE NORTHERN FOOTHILLS AND NW
PIEDMONT, BUT READERS SHOULD NOTE THAT GSP HAS ENDED OUR
FROST/FREEZE PROGRAM FOR THE SEASON. THUS, NO ADVISORIES WILL BE
ISSUED. THE SFC HIGH WILL REMAIN IN A GOOD POSITION TO RIDGE DOWN
THE EAST SIDE OF THE APPALACHIANS AS A DRY WEDGE TODAY. THE
RESULTING COOL NORTHEAST SFC FLOW SHOULD KEEP TEMPS ABOUT FIVE
DEGREES BELOW NORMAL FOR HIGHS, EVEN WITH WHAT SHOULD BE PLENTY OF
SUN, AT LEAST EARLY IN THE DAY. HIGH CLOUDS WILL THICKEN FROM THE
WEST THIS AFTERNOON AS A CONVEYOR BELT OF MOISTURE APPROACHES AHEAD
OF THE NEXT SYSTEM. PRESENT INDICATIONS ARE THAT THE LEADING EDGE OF
ANY PRECIP WILL NOT REACH THE FORECAST AREA FROM THE WEST BEFORE
SUNSET.
SHORT TERM /TONIGHT THROUGH FRIDAY/
AS OF 235 PM TUE: A COLD AIR DAMMING HIGH WILL BE IN PLACE TO START
THE PERIOD. A SHORT WAVE CROSSES THE AREA WITH INCREASINGLY MOIST
SOUTHERLY FLOW AHEAD OF THE ASSOCIATED APPROACHING COLD FRONT. WHILE
INITIALLY DRY, THE ATMOSPHERE MOISTENS QUICKLY IN THE STRONG
SOUTHERLY FLOW. THE INCREASING MOISTURE, COMBINED WITH THE SYNOPTIC
FORCING FROM THE SHORT WAVE AND ISENTROPIC LIFT, WILL LEAD TO
INCREASING PRECIP CHANCES, INITIALLY ACROSS THE MOUNTAINS WEDNESDAY
NIGHT, THEN ACROSS THE ENTIRE AREA BY THURSDAY MORNING. THE FRONT
MOVES RELATIVELY QUICKLY ACROSS THE AREA WITH PRECIP ENDING BY LATE
IN THE DAY OR EARLY IN THE EVENING THURSDAY. DRY HIGH PRESSURE WITH
DECREASING CLOUDS EXPECTED FOR FRIDAY.
THERMAL PROFILES SHOW A COLD AND DRY AIR MASS IN PLACE ALONG AND
NEAR THE BLUE RIDGE AT PRECIP ONSET. WET BULB TEMPS LOOK TO BE NEAR
BUT ABOVE FREEZING, SO PRECIP SHOULD BE RAIN EVEN IN THESE AREAS.
HOWEVER, THE COLD AIR JUST ABOVE THE SURFACE AND UNDER THE
STRENGTHENING WARM NOSE, WILL LIKELY LEAD TO A BRIEF PERIOD OF SLEET
AT PRECIP ONSET. THIS SLEET COULD FALL ACROSS A LARGE PORTION OF
THE AREA BEFORE QUICKLY TRANSITIONING TO RAIN. THIS IS A COMMON
OCCURRENCE IN THESE TYPES OF SITUATIONS WITH NO MORE THAN A "GEE
WHIZ" AMOUNT OF SLEET. BREEZY WINDS ARE ALSO EXPECTED THURSDAY WITH
THE CAD IN PLACE, THEN AGAIN ON FRIDAY BEHIND THE COLD FRONT.
LOWS WEDNESDAY NIGHT WILL BE A FEW DEGREES ABOVE NORMAL. HIGHS
THURSDAY WILL HAVE A TYPICAL CAD SET UP WITH TEMPS 10 TO 15 DEGREES
BELOW NORMAL FOR ALL BUT THE VALLEYS NEAR THE TN BORDER WHERE NEAR
NORMAL TEMPS ARE EXPECTED. LOWS THURSDAY NIGHT WARM A FEW DEGREES
ACROSS THE MOUNTAINS AND COOL SLIGHTLY OR REMAIN NEARLY STEADY
ELSEWHERE. HIGHS FRIDAY WILL BE NEAR TO SLIGHTLY BELOW NORMAL.
LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/
AS OF 210 AM TUE: SURFACE HIGH PRESSURE AND WARMING TEMPS EXPECTED
FOR THE WEEKEND AS AN UPPER RIDGE BUILDS OVER THE EASTERN CONUS. A
SHORT WAVE DENTS THE RIDGE SUNDAY NIGHT WITH A COLD FRONT MOVING
ACROSS THE MID ATLANTIC MONDAY. THE RIDGE REBUILDS LATE MONDAY
BEFORE A SHORT WAVE MOVING UP THE RIDGE ON TUESDAY BRINGS A
WEAKENING COLD FRONT TOWARD THE AREA FROM THE WEST. THE RESULT IS A
DRY FORECAST THROUGH THE PERIOD WITH TEMPS RISING ABOVE NORMAL
THROUGH MONDAY THEN DROPPING A FEW DEGREES ON TUESDAY.
AVIATION /06Z WEDNESDAY THROUGH SUNDAY/
AT KCLT AND ELSEWHERE: DRY AND VFR THROUGH THE 06Z FORECAST PERIOD
ACROSS THE TERMINALS THROUGH MOST OF THE TAF PERIOD. FOG FORMATION
IS NOT EXPECTED AT ANY OF THE TERMINALS THROUGH DAYBREAK THANKS TO
DRIER AIR FILTERING INTO THE REGION. DRY HIGH PRESSURE WILL REMAIN
IN PLACE THROUGH THIS EVENING BEFORE A COLD FRONT APPROACHING OUT OF
THE WEST INCREASES CLOUD COVER AND RAIN CHANCES TONIGHT INTO EARLY
THURSDAY MORNING. RAIN CHANCES SHOULD HOLD OFF AT KAVL, KHKY AND THE
SC UPSTATE TERMINALS UNTIL AFTER THE 06Z TAF PERIOD. HOWEVER, RAIN
WILL LIKELY REACH KCLT TOWARDS THE END OF THE 06Z TAF PERIOD, AS
THIS TAF FORECAST GOES OUT 30 HOURS. HAVE A PROB30 AT KCLT TO
ACCOUNT FOR RAIN, LOWERING CIGS, AND LOWERING VSBYS FROM 08Z-12Z
THURSDAY. WINDS WILL REMAIN SE'LY AT KAVL AND NE'LY AT THE REST OF
THE TERMINALS THROUGH THE ENTIRE TAF PERIOD. LOW-END GUSTS SHOULD
DEVELOP LATER THIS MORNING ACROSS THE SC UPSTATE TERMINALS. GUSTS
SHOULD LINGER THROUGH AT LEAST THE AFTERNOON/EARLY EVENING HOURS.
GUSTS MAY EVEN LINGER THROUGH THE END OF THE 06Z TAF PERIOD ACROSS
THE SC UPSTATE TERMINALS BUT CONFIDENCE WAS TOO LOW KEEP THE GUST
MENTION THAT LONG. CLOUD COVER SHOULD REMAIN VFR (OUTSIDE OF KCLT)
BUT WILL GRADUALLY THICKEN THIS AFTERNOON, BECOMING OVC BY EARLY
THIS EVENING.
OUTLOOK: A COLD FRONT WILL BRING RAIN AND RESTRICTIONS TO THE
TERMINALS WEDNESDAY NIGHT INTO THURSDAY. HIGH PRESSURE BRINGS DRY
AND VFR CONDITIONS BACK FRIDAY INTO THE WEEKEND.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
SYNOPSIS...AR/RWH
NEAR TERM...AR/JDL/PM
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...AR
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