306
FXUS62 KGSP 171717
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
117 PM EDT THU JUL 17 2025
SYNOPSIS
DAILY THUNDERSTORM CHANCES CONTINUE THROUGH THE UPCOMING WEEKEND. A
FEW STORMS COULD PRODUCE DAMAGING WIND GUSTS AND LOCALIZED FLASH
FLOODING. HOT AND HUMID CONDITIONS STICK AROUND THROUGH THE
FORECAST PERIOD.
NEAR TERM /THROUGH FRIDAY/
AS OF 115 PM EDT THURSDAY: A STRONG SURFACE HIGH REMAINS PARKED OVER
THE ATLANTIC AND THE WESTERN SIDE AMPLIFYING, KEEPING THE FLUX OF
MOISTURE IN PLACE. OFF TO THE NORTH, AN AREA OF LOW PRESSURE MOVES
OUT TO THE FAR NE, DRAGGING A VERY WEAK FRONTAL BOUNDARY TOWARD THE
TN VALLEY. THIS IS EXPECTED TO SETTLE OVER THE MOUNTAINS THIS
AFTERNOON, AIDING IN SLIGHTLY MORE FORCING FOR CONVECTIVE
DEVELOPMENT. ALL OTHER INGREDIENTS REMAIN IN PLACE MUCH LIKE THE
PAST WEEK. GUIDANCE HAS PWATS IN THE 1.75-2.00 INCH RANGE AND
RELATIVELY WEAK STEERING FLOW ALOFT. FOR TODAY, ANOTHER ROUND OF THE
TYPICAL SHOWERS AND THUNDERSTORM ACTIVITY STARTING OVER THE
MOUNTAINS AND EVENTUALLY MAKING ITS WAY EAST. CAM GUIDANCE SHOWS
MORE ACTIVITY OVER THE MOUNTAINS WITH HIGHER CHANCES (65-85%),
ESPECIALLY OVER THE RIDGETOPS. EAST OF THE MOUNTAINS, POPS DROP OFF
DRASTICALLY INTO THE SLIGHT CHANCE (15-35%) RANGE DURING THE TYPICAL
PEAK HEATING TIME FRAME. ANY STORM THAT CAN FIRE OFF HAS THE
POTENTIAL TO PRODUCE LOCALLY HIGHER RAIN RATES AND AN ISOLATED/LOCAL
FLASH FLOODING RISK. OVERNIGHT, POPS DECREASE QUICKLY, BUT CANNOT
RULE OUT A POP-UP SHOWER OR THUNDERSTORM BEFORE MIDNIGHT. FOR
FRIDAY, A SURFACE HIGH MIGRATES EAST FROM THE CENTRAL CONUS ALONG
WITH THE HIGH OVER THE ATLANTIC. IN BETWEEN THE TWO HIGHS SITS THE
CWA, ALLOWING FOR CONTINUED MOISTURE ADVECTION AND THE TYPICAL
DIURNALLY DRIVEN CONVECTION CHANCES. AGAIN, THE HIGHER CHANCES ARE
OVER THE MOUNTAINS (60-80%) AND ELSEWHERE 20-40%. TEMPERATURES
REMAIN IN THE LOW 90S TODAY BUT HEAT UP MORE FOR FRIDAY. THE HEAT
INDEX LOOKS TO BE A BIT MORE OF AN ISSUE STARTING TOMORROW. MANY
LOCATIONS EAST OF THE MOUNTAINS COULD SEE HI VALUES IN THE 100-104
RANGE, BUT REMAINS JUST BELOW HEAT ADVISORY CRITERIA AT THIS TIME.
SHORT TERM /FRIDAY NIGHT THROUGH MONDAY/
AS OF 1245 PM EDT THURSDAY: A FAIRLY ACTIVE PATTERN IS EXPECTED OVER
THE WEEKEND THRU MONDAY, AS UPPER RIDGE RETROGRADES SLIGHTLY TO THE
NORTHERN GULF COAST, AND HEIGHTS FALL ACROSS THE MID-ATLANTIC. THIS
WILL ALLOW A QUASI-STATIONARY FRONT TO SLOWLY SAG SOUTHWARD ACROSS
THE OHIO VALLEY AND MID-ATLANTIC. A TYPICAL HOT AND HUMID AIR MASS
IN PLACE COMBINED WITH EXTRA FOCUS FOR CONVECTION NEAR THE FRONTAL
BOUNDARY WILL RESULT IN CATEGORICAL POPS IN THE NC MOUNTAINS
TO SOLID CHC POPS ACROSS THE I-85 CORRIDOR AND SOUTHEAST EACH
DAY. GENERALLY, POPS WILL BE THE TYPICAL DIURNAL AFTN TO EARLY
EVENING TIME FRAME, BUT SOME INCREASE IN SHEAR ALONG A "RING OF
FIRE" AROUND THE UPPER RIDGE MAY SUPPORT MCS ACTIVITY MAKING A RUN
FOR THE SOUTHERN APPALACHIANS EITHER SUNDAY OR MONDAY. CONFIDENCE
IS STILL LOW ON THAT. THERE MAY ALSO BE AN INCREASING FLASH FLOOD
THREAT, AS ELEVATED PWATS IN THE 2-2.25" RANGE WILL PERSIST ACROSS
THE AREA THRU MONDAY. THE AREA OF MOST CONCERN WILL BE IN THE NC
MOUNTAINS NEAR THE TN BORDER THANKS TO THE PERSISTENT WESTERLY
UPSLOPE FLOW. ANOTHER CONCERN WILL BE THE HEAT INDEX, AS DEWPTS
MAY NOT MIX OUT AS MUCH AHEAD OF THE SAGGING FRONT, WHILE TEMPS
GET INTO THE MID 90S ACROSS MOST OF THE PIEDMONT. THE NBM DEWPTS
MAY BE A TAD HIGH, BUT THE LATEST FORECAST IS FOR PLENTY OF 105-109
HEAT INDICES ACROSS THE LOWER PIEDMONT AND THE CHARLOTTE AREA EACH
AFTN THRU MONDAY.
LONG TERM /MONDAY NIGHT THROUGH THURSDAY/
AS OF 100 PM EDT THURSDAY: UPPER RIDGING BEGINS TO REASSERT
ITSELF FROM THE LOWER MS VALLEY TOWARD THE EAST TUESDAY INTO
WEDNESDAY. THIS WILL ALLOW DRIER AIR TO WORK IN FROM THE NORTH
AND BRING POPS BACK DOWN CLOSER TO CLIMO. TEMPS WILL REMAIN ABOVE
NORMAL, BUT DEWPTS SHOULD MIX OUT MORE AND BRING HEAT INDICES BACK
UNDER HEAT ADVISORY CRITERIA FOR MOST OF THE FORECAST AREA.
AVIATION /17Z THURSDAY THROUGH MONDAY/
AT KCLT AND ELSEWHERE: CONDITIONS FOR THIS TAF PERIOD REMAIN MOSTLY
VFR ACROSS THE TERMINALS. TSRA CHANCES ONCE AGAIN FOR THE MOUNTAIN
SITES AND KCLT THIS AFTERNOON AND EVENING. CONFIDENCE IS HIGHER
ACROSS THE MOUNTAINS, WHICH WILL KEEP A TEMPO GOING AT KAVL/KHKY. A
PROB30 REMAINS IN PLACE FOR KCLT AS THE CONFIDENCE IS LOWER. TSRA
SHOULD START TO TAPER OFF BY MIDNIGHT. OVERNIGHT, THERE IS A CHANCE
ONCE AGAIN FOR LOW STRATUS OR BR TO FORM, WHICH COULD DROP CIGS INTO
THE MVFR CATEGORY AND CLEAR AFTER SUNRISE. WINDS TODAY REMAIN SW
WITH LOW-END GUSTS POSSIBLE AT KCLT/KGSP/KGMU THROUGH 00Z. ANOTHER
ROUND OF TSRA POSSIBLE FRIDAY, MAINLY AT THE MOUNTAIN SITES. WILL
KEEP A PROB30 FOR THE AFTERNOON. WINDS FRIDAY ALSO REMAIN SW WITH A
FEW BRIEF LOW-END GUSTS POSSIBLE AT THE END OF THE TAF PERIOD.
OUTLOOK: THUNDERSTORM CHANCES EACH AFTERNOON/EVENING. LOW STRATUS
OR FOG ARE POSSIBLE EACH MORNING IN MOUNTAIN/RIVER VALLEYS.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
SYNOPSIS...ARK
NEAR TERM...CP
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...CP
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page