483
FXUS62 KGSP 242342
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
742 PM EDT THU SEP 24 2026
WHAT HAS CHANGED
NO MAJOR CHANGES TO THE PUBLIC FORECAST.
THE AVIATION FORECAST WAS UPDATED TO REFLECT THE RECENT 00Z TAF
ISSUANCE.
KEY MESSAGES
1. LINGERING SHOWERS WILL TAPER OFF BY EVENING AS DRIER STARTS
MOVING IN, BUT PATCHY DENSE FOG IS POSSIBLE THROUGH LATE
TONIGHT. OTHERWISE, TEMPERATURES REMAIN COOL FRIDAY BEFORE
RETURNING TO NORMAL THROUGH THE WEEKEND.
DISCUSSION
KEY MESSAGE 1: LINGERING SHOWERS WILL TAPER OFF BY EVENING AS DRIER
STARTS MOVING IN, BUT PATCHY DENSE FOG IS POSSIBLE THROUGH LATE
TONIGHT. OTHERWISE, TEMPERATURES REMAIN COOL FRIDAY BEFORE RETURNING
TO NORMAL THROUGH THE WEEKEND.
THE LOSS OF DAYTIME HEATING AND ANY PALTRY INSTABILITY OVER
THE SMOKIES AND BALSAMS HAS BROUGHT SHOWERS TO HEEL FOR THE
EVENINGS...SO STILL EXPECTING A DRY NIGHT AHEAD. STILL SEEING
WIDESPREAD LOW CLOUDS EAST OF THE MOUNTAINS, BUT THERE ARE HINTS
ALREADY OF THAT MOISTURE BEGINNING TO SCOUR OUT...WITH SATELLITE
IMAGERY DEPICTING DRYING AND CLEARING NORTH OF I-40 AND DRAWING
CLOSER.
THE WEDGE SHOULD START BREAKING DOWN AS WE GET INTO THIS EVENING
AND THE UPPER LOW OVER WV THIS PAST MORNING ROTATES SOUTHEASTWARD
ACROSS THE CAROLINAS THROUGH THE END OF THE DAY. ONCE THIS HAPPENS,
THE FLOW BACKING MORE NORTHERLY AND NORTHWESTERLY WILL DRAIN THE
COOL POOL EAST OF THE MTNS AND THAT WILL BE IT, WITH MOST OF THE
SKY BECOMING CLEAR BY DAYBREAK. THE ONLY MINOR PROBLEM COULD
BE THE POTENTIAL FOR SOME DENSE FOG TO DEVELOP AS THE DRY AIR
COMES IN ALOFT FIRST AND WE HAVE PLENTY OF LINGERING MOISTURE
AT THE SFC. MANY TIMES IN SIMILAR SITUATIONS, WE GET A PERIOD
OF A FEW HOURS WHERE PATCHY DENSE FOG DEVELOPS, SOMETIMES TO THE
POINT WHERE A DENSE FOG ADVISORY NEEDS TO BE ISSUED. THE GUIDANCE
DOESN'T SUPPORT IT RIGHT NOW, BUT THE POSSIBILITY EXISTS AND WE
WILL MONITOR FOR FOG DEVELOPMENT AFTER DARK.
FROM FRIDAY ONWARD, IT LOOKS LIKE SMOOTH SAILING. THE MODELS SHOW
US TRAPPED UNDER A COOL AND DRY CYCLONIC N TO NW FLOW ALOFT THROUGH
AT LEAST MONDAY, WHICH WILL PRECLUDE ANY RAIN. TEMPS STAY COOL ON
FRIDAY WITH HIGHS AROUND FIVE DEGREES BELOW NORMAL, AND PERHAPS
DOWNRIGHT CHILLY FOR LOW TEMPS EARLY SATURDAY MORNING WITH LOTS OF
PLACES DROPPING DOWN TO 45-50 DEGREES. RIDGETOPS ABOVE 5000 FEET
COULD GET DOWN IN THE UPPER 30S! THE SFC HIGH RESPONSIBLE FOR THIS
COOL-DOWN WILL BE STUCK TO OUR NORTH THROUGH THE WEEKEND AS IT WILL
BE BLOCKED BY THE BIG CUTOFF LOW OVER THE NORTHEAST, SO AS A RESULT
THE AIR MASS WILL REMAIN IN-PLACE AND SHOULD SLOWLY MODIFY WITH
TEMPS RETURNING TO SEASONAL NORMALS OVER THE WEEKEND. IT SHOULD BE
SPECTACULAR EARLY AUTUMN WEATHER. THE PATTERN GETS UN-STUCK DURING
THE MIDDLE PART OF THE WEEK WITH WARMER TEMPERATURES, BUT BY THEN,
MODEL DIFFERENCES INJECT A GREAT DEAL OF UNCERTAINTY INTO THE
FORECAST. EVENTUALLY AS WE GET INTO THE LATTER HALF OF THE NEXT
WEEK, RAIN CHANCES WILL RETURN AS MOISTURE COMES BACK UP FROM THE
SOUTH, BUT DETAILS ARE VERY SKETCHY.
AVIATION /00Z FRIDAY THROUGH TUESDAY/
AT KCLT AND ELSEWHERE: LINGERING MVFR CEILINGS IN A FEW SPOTS SHOULD
CONTINUE TO IMPROVE OVER THE NEXT FEW HOURS, WITH PREVAILING
VFR EXPECTED IN MOST LOCATIONS BY MIDNIGHT, IF NOT EARLIER.
THE EXCEPTION WILL BE SHELTERED AREAS IN THE NC FOOTHILLS,
AND OF COURSE THE MOUNTAIN VALLEYS, BOTH OF WHICH WILL SEE AT
LEAST INTERMITTENT MVFR CEILINGS AND FOG THROUGH MUCH OF TONIGHT.
STILL THINK ALSO THAT AREAS OF LINGERING LOW-LEVEL MOISTURE WILL
MANAGE TO DEVELOP INTO FOG AS CLEARING AND DRYING ALOFT OCCURS
OVERNIGHT...SO THERE'S A BIG FAT QUESTION MARK AS TO WHETHER
SITES EVEN IN THE UPSTATE AND PIEDMONT COULD SEE BRIEF DENSE FOG.
THAT'S NOT INCLUDED IN ANY OF THE TAFS SINCE CONFIDENCE IS SIMPLY
TOO LOW, BUT IT'S A REAL POSSIBILITY. OTHERWISE...A CLEAR, DRY
DAY WITH A LIGHT NE WIND IS STILL EXPECTED FOR FRIDAY, WITH SKC
LIKELY TO PERSIST INTO FRIDAY NIGHT.
OUTLOOK: VFR SHOULD PERSIST INTO THE MIDDLE OF NEXT WEEK, THOUGH
MOUNTAIN/RIVER VALLEY FOG/STRATUS COULD STILL DEVELOP BEFORE
DAYBREAK EACH DAY.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
MPR/PM
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