987
FXUS62 KGSP 130229
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
929 PM EST TUE NOV 12 2024
SYNOPSIS
DRY HIGH PRESSURE REMAINS IN PLACE THROUGH WEDNESDAY. CLOUDS AND
PRECIPITATION ARRIVING LATE WEDNESDAY NIGHT WILL MAKE FOR A VERY
DAMP AND CHILLY THURSDAY. DRY WEATHER A WARMING TREND EXPECTED
FRIDAY THROUGH THE WEEKEND. DRY AND WARM CONDITIONS CONTINUE EARLY
NEXT WEEK.
NEAR TERM /THROUGH WEDNESDAY/
AS OF 925 PM EST TUESDAY: HIGH PRESSURE WILL REMAIN CENTERED OVER
QUEBEC TONIGHT, SUPPORTED BY A SLOW-MOVING FULL-LATITUDE MID/UPPER
RIDGE, THE AXIS OF WHICH WILL APPROACH OUR AREA FROM THE WEST
TONIGHT AND MOVE OVERHEAD WEDNESDAY. THE AIR MASS BUILDING DOWN FROM
THE HIGH TO THE NORTH TONIGHT WILL BE MUCH COOLER AND DRIER THAN
WHAT WE HAVE OBSERVED LATELY. GUIDANCE FINALLY SHOWS LOW TEMPS
TONIGHT DROPPING DOWN CLOSE TO SEASONAL NORMS. THIS COULD BRING SOME
FREEZING TEMPS TO THE MOUNTAINS AND SOME FROST POTENTIAL TO THE NRN
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 ON WEDNESDAY.
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 IN THE 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 /WEDNESDAY NIGHT 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 /03Z WEDNESDAY THROUGH SUNDAY/
AT KCLT AND ELSEWHERE: DRIER AIR WILL CONTINUE FILTERING INTO THE
AREA OVERNIGHT, WITH VFR CONDITIONS EXPECTED TO PERSIST THROUGH THIS
FORECAST PERIOD. SOME PATCHY FOG WILL NEVERTHELESS BE POSSIBLE IN
THE MOUNTAINS VALLEYS, BUT THIS IS UNLIKELY TO IMPACT KAVL. LIGHT NE
WIND THIS EVENING IS EXPECTED TO STEADILY INCREASE THROUGH THE
OVERNIGHT, WITH MOST TERMINALS EXPECTED TO BE AROUND 10 KTS BY
SUNRISE. MIGHT SEE OCCASIONAL GUSTS AT SOME LOCATIONS AS WE MIX
DEEPER AFTER MID-MORNING AS THE PRESSURE GRADIENT IMPROVES. HIGH
CLOUDS WILL BEGIN TO THICKEN WEDNESDAY AFTERNOON AHEAD OF THE NEXT
FRONTAL SYSTEM.
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...RWH
NEAR TERM...JDL/PM
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...JDL/PM
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