596
FXUS62 KGSP 160554
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
154 AM EDT TUE SEP 16 2025
SYNOPSIS
A COASTAL LOW MEANDERS OVER EASTERN NORTH CAROLINA THROUGH TONIGHT
KEEPING SHOWER AND THUNDERSTORM CHANCES AS WELL BELOW NORMAL HIGH
TEMPERATURES AROUND. THE COASTAL LOW LIFTS NORTHWARD TOWARDS THE MID-
ATLANTIC MID TO LATE WEEK WHILE WEAK SURFACE HIGH PRESSURE BUILDS
BACK OVER THE SOUTHEAST, ALLOWING DRIER CONDITIONS TO RETURN. HIGH
TEMPERATURES END UP NEAR NORMAL WEDNESDAY BEFORE TRENDING ABOVE
NORMAL THURSDAY INTO THE WEEKEND DESPITE SHOWER AND THUNDERSTORM
CHANCES POSSIBLY RETURNING OVER THE WEEKEND.
NEAR TERM /THROUGH TONIGHT/
AS OF 145 AM TUE: SCATTERED SHOWERS WILL LINGER EARLY THIS MORNING
ALONG AND WEST OF THE I-26 CORRIDOR. THESE SHOULD DISSIPATE BEFORE
DAYBREAK. MOUNTAIN VALLEY FOG IS EXPECTED TO DEVELOP ONCE AGAIN
AFTER THE SHOWERS AND CONVECTIVE DEBRIS CLOUDS DISSIPATE.
ANOTHER SHORT WAVE IS EXPECTED TO ROTATE AROUND THE UPPER LOW OVER
EASTERN NC AND MOVE ACROSS THE AREA THIS AFTERNOON AND EVENING. THE
SURFACE RIDGE OVER THE AREA WEAKENS AS A LOW PRESSURE SYSTEM MOVES
NORTH ACROSS THE NORTHERN NC COAST THIS AFTERNOON INTO VA THIS
EVENING. THERE WILL BE SOME MOISTURE TRANSPORT INTO THE AREA ON THE
EASTERLY FLOW ASSOCIATED WITH THE LOW, BUT DEEPER MOISTURE AND
STRONGER FORCING REMAIN TO OUR EAST. STILL, INSTABILITY IS EXPECTED
TO DEVELOP ONCE AGAIN, THIS COMBINED WITH LINGERING LOW LEVEL
MOISTURE AND FORCING FROM THE SHORT WAVE, SCATTERED CONVECTION IS
EXPECTED ACROSS THE MOUNTAINS WITH ISOLATED CONVECTION DROPPING
SOUTH ACROSS THE WESTERN UPSTATE AND NE GA. ISOLATED TO SCATTERED
SHOWERS WILL MOVE INTO THE NC FOOTHILLS AND PIEDMONT ON THE EASTERLY
FLOW AROUND THE LOW. OVERALL, QPF WILL BE LIGHT, BUT BRIEF, HEAVY
RAINFALL WILL BE POSSIBLE IN ANY STORM. HIGHS WILL BE UP TO 5
DEGREES BELOW NORMAL, ON THE COOLER SIDE WHERE CLOUDS ROTATE IN AND
SHOWERS DEVELOP.
SHOWERS TAPER OFF THROUGH THE EVENING AS INSTABILITY WEAKENS, AND
THE SHORT WAVE AND SURFACE LOW ROTATE AWAY FROM THE AREA. SOME
CLOUDS WILL LINGER OVER THE I-40 CORRIDOR BUT SHOULD CLEAR OUT
ELSEWHERE. MOUNTAIN VALLEY FOG LIKELY TO FORM ONCE AGAIN. LOWS WILL
BE A FEW DEGREES BELOW NORMAL.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/
AS OF 100 AM EDT TUESDAY...
KEY MESSAGES:
1) WARMING TREND CONTINUES AS DRIER CONDITIONS RETURN
2) NEAR NORMAL HIGHS ON WEDNESDAY WITH ABOVE NORMAL HIGHS ON THURSDAY
3) HUMIDITY INCREASES SLIGHTLY THURSDAY, MAINLY EAST OF THE MOUNTAINS
THE UPPER LOW LIFTS NORTHEAST AWAY FROM THE REGION WHILE GRADUALLY
WEAKENING THROUGH THE PERIOD. THE ASSOCIATED COASTAL LOW LIFTS
NORTHWARD TOWARDS THE MID-ATLANTIC THROUGH EARLY THURSDAY BEFORE
TAKING A NORTHEASTWARD TURN LATE THURSDAY INTO DAYBREAK FRIDAY WHILE
GRADUALLY WEAKENING. MEANWHILE, WEAK SURFACE HIGH PRESSURE BUILDS
BACK OVER THE SOUTHEAST ALLOWING DRIER CONDITIONS TO RETURN DURING
THE PERIOD. BOTH THE 00Z CAMS AND 00Z GLOBAL MODELS DEPICT THE
POTENTIAL FOR SOME SPOTTY SHOWERS TO RETURN EACH DAY BUT CONFIDENCE
IS LOW AS COVERAGE SHOULD BE LOWER COMPARED TO EARLIER IN THE WEEK
WITH BOTH THE UPPER LOW AND COASTAL LOW LIFTING AWAY FROM THE
REGION. THE WARMING TREND CONTINUES WITH TEMPS TICKING UP A FEW
DEGREES EACH DAY/NIGHT. NEAR NORMAL HIGHS ARE EXPECTED ON WEDNESDAY,
WITH HIGHS ON THURSDAY RUNNING ~3-5 DEGREES ABOVE NORMAL. HUMIDITY
INCREASES SLIGHTLY THURSDAY, MAINLY EAST OF THE MOUNTAINS, AS
SURFACE WINDS TOGGLE SOUTHWEST. LOWS EACH NIGHT WILL REMAIN A FEW
DEGREES ABOVE NORMAL.
LONG TERM /FRIDAY THROUGH MONDAY/
AS OF 130 AM EDT TUESDAY...
KEY MESSAGES:
1) WARMING TREND CONTINUES THROUGH FRIDAY
2) COOLING TREND BEGINS SATURDAY, LINGERING THROUGH MONDAY
3) MOSTLY DRY AGAIN FRIDAY WITH SHOWER AND THUNDERSTORM CHANCES
POSSIBLY RETURNING THIS WEEKEND AND LINGERING ON MONDAY
WEAK UPPER RIDGING BUILDS OVER THE SOUTHEAST FRIDAY INTO THE WEEKEND
BEFORE UPPER TROUGHING PUSHING TOWARDS THE REGION MONDAY. AT THE
SFC, A COLD FRONT APPROACHES OUT OF THE NORTH FRIDAY INTO DAYBREAK
SATURDAY BEFORE THE SOUTHWESTERN PERIPHERY OF HIGH PRESSURE NOSES
DOWN INTO THE SOUTHEAST SATURDAY INTO MONDAY. MOSTLY DRY CONDITIONS
LINGER THROUGH AT LEAST THE MORNING HOURS ON SATURDAY BEFORE SHOWER
AND THUNDERSTORM CHANCES RETURN THE REMAINDER OF THE PERIOD.
HOWEVER, CONFIDENCE IS LOW AS 00Z GLOBAL MODELS ARE NOT IN AGREEMENT
REGARDING THE EXACT COVERAGE OR TIMING OF CONVECTION. 00Z GLOBAL
GUIDANCE SEEMS TO GENERALLY AGREE ON POPS RETURNING SATURDAY.
HOWEVER, THE GFS IS DRY SUNDAY INTO MONDAY WHILE THE ECMWF KEEPS
WETTER CONDITIONS AROUND. THE CANADIAN LIES SOMEWHERE IN BETWEEN.
THUS, NBM POPS BEING LIMITED TO CHANCE THIS WEEKEND INTO EARLY NEXT
WEEK SEEMS REASONABLE. THE WARMING TREND CONTINUES THROUGH FRIDAY
NIGHT BEFORE A COOLING TREND DEVELOPS THE REST OF THE PERIOD. FRIDAY
SHOULD END UP BEING THE WARMEST DAY OF THE WEEK WITH HIGHS TRENDING
SEVERAL DEGREES ABOVE NORMAL. AFTERNOON TEMPS ON FRIDAY SHOULD CLIMB
INTO THE MID TO UPPER 80S ACROSS THE MOUNTAIN VALLEYS AND EAST OF
THE MOUNTAINS. HIGHS ON SATURDAY SHOULD BE A FEW DEGREES COOLER BUT
STILL ~4-6 DEGREES ABOVE NORMAL. DESPITE THE COOLING TREND
CONTINUING, HIGHS ON BOTH SUNDAY AND MONDAY SHOULD END UP JUST ABOVE
NORMAL. LOWS EACH NIGHT SHOULD REMAIN ~4-7 DEGREES ABOVE NORMAL.
AVIATION /06Z TUESDAY THROUGH SATURDAY/
AT KCLT AND ELSEWHERE: LINGERING SHOWERS EARLY THIS MORNING WILL
AFFECT KAVL AND POSSIBLY THE UPSTATE SITES. THE SHOWERS SHOULD
DISSIPATE BEFORE DAYBREAK. MOUNTAIN VALLEY FOG EXPECTED ONCE THE
CONVECTIVE DEBRIS DISSIPATES AND HAVE RESTRICTIONS AT KAVL.
SCATTERED CONVECTION EXPECTED TO REDEVELOP ACROSS THE MOUNTAINS BY
AFTERNOON WHICH WILL LIKELY DRIFT INTO THE UPSTATE. FOR NOW, ONLY
KAVL GETS A PROB30 WHERE CHANCE IS HIGHEST. CONFIDENCE STILL TOO LOW
FOR ONE AT THE UPSTATE SITES, BUT THESE MAY BE ADDED LATER.
OTHERWISE, EXPECT SCT LOWER VFR CLOUDS AND BKN MID OR HIGH CLOUDS
THROUGH THE DAY INTO THE EVENING. GUIDANCE HAS BACKED OFF ON MVFR
POTENTIAL AT KCLT AND KHKY OVERNIGHT. WILL HAVE TO KEEP AN EYE ON
THIS AS WE GET CLOSER IN TIME AS THERE IS STILL A CHANCE THEY MAY
MAKE A RUN AT THOSE SITES. MOUNTAIN VALLEY FOG LIKELY AGAIN AS WELL.
LIGHT N WIND THIS MORNING BECOMES GUSTY FOR THE AFTERNOON AT KCLT.
THE UPSTATE SITES WILL SEE N WIND BECOMING NW TO WNW FOR THE
AFTERNOON, THEN BACK TO LIGHT N BY EVENING.
OUTLOOK: RAIN CHANCES AND POTENTIAL RESTRICTIONS WILL STICK AROUND
WEDNESDAY. DRY CONDITIONS THEN EXPECTED THROUGH SATURDAY. SOME
MOUNTAIN VALLEY FOG WILL REMAIN POSSIBLE WHERE CLOUDS DO NOT INHIBIT
NOCTURNAL RADIATION.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
SYNOPSIS...AR
NEAR TERM...RWH
SHORT TERM...AR
LONG TERM...AR
AVIATION...RWH
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