286
FXUS62 KGSP 030550
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
150 AM EDT THU JUL 3 2025
SYNOPSIS
ANOTHER COLD FRONT DROPS SOUTH FROM THE GREAT LAKES TODAY BRINGING
DRIER WEATHER FOR THE INDEPENDENCE DAY HOLIDAY WEEKEND. TEMPERATURES
REMAIN TYPICAL FOR THE SUMMERTIME SEASON THROUGH THE BEGINNING OF
NEXT WEEK. DAILY AFTERNOON AND EVENING SHOWER AND THUNDERSTORM
CHANCES RETURN AT THE BEGINNING OF NEXT WEEK.
NEAR TERM /THROUGH TONIGHT/
AS OF 140 AM: ALTHOUGH LEADING EDGE OF WEAK SURFACE BOUNDARY
ATTENDING THE PASSAGE OF AN UPPER LEVEL TROUGH HAS PUSHED JUST
S=>E OF THE FORECAST AREA. AMPLE MOISTURE AND LINGERING MODERATE
INSTABILITY NORTH OF THE SUBTLE WIND SHIFT HAS YIELDED DEVELOPMENT
OF ISOLATED DEEP CONVECTION ACROSS THE PIEDMONT SINCE LATE WED
EVENING. WE'VE EVEN SEEN A COUPLE OF STRONG UPDRAFT PULSES. HAVING
SAID THAT, THE ACTIVITY HAS BEEN TRENDING WEAKER OVER THE PAST
HOUR, AND WE DO NOT EXPECTED IT TO LINGER FOR MORE THAN ANOTHER 1-2
HOURS. OTHERWISE, LOWER THETA-E AIR HAS FILTERED INTO THE NW HALF
OF THE AREA, WITH SURFACE DEWPOINTS IN THE LOWER/MID 60S OBSERVED
ACROSS MUCH OF THE MOUNTAINS AND FOOTHILLS. THIS DRIER AIR WILL
CONTINUE TO GRADUALLY FILTER THROUGH THE REMAINDER OF THE CWA
THROUGH THE DAY, WHICH WILL COMBINE WITH WARMING MID-LEVEL TEMPS TO
RESULT IN ROBUST DIURNAL INSTABILITY SHUNTING SOUTH AND EAST OF THE
AREA THIS AFTERNOON. OTHER THAN PERHAPS SOME SPOTTY SHOWERS OVER THE
SOUTHERN MOUNTAINS, DIURNAL CONVECTION IS NOT EXPECTED TODAY. TEMPS
ARE EXPECTED TO BE 0-2 DEGREES ABOVE CLIMO THROUGH THE PERIOD.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/
AS OF 130 AM THURSDAY: INDEPENDENCE DAY AND THE WEEKEND LOOK TO BE
RELATIVELY PLEASANT FOR SUMMER AND FIREWORKS. FLOW ALOFT REMAINS
BROAD AS A WEAKENING RIDGE OVER THE CENTRAL CONUS SLIDES EASTWARD.
IN RESPONSE, A SURFACE HIGH PARKS ITSELF OVER THE AREA AND THE
EASTERN PORTION OF THE COUNTRY. LIGHT SURFACE WINDS TURN MORE NE AS
THE HIGH REMAINS TO THE NORTH OF THE CWA. WITH THE HIGH PRESSURE,
MUCH DRIER AIR FILTERS INTO THE AREA THROUGH THE SHORT TERM,
SHUNTING MOST RAIN CHANCES. AT THIS TIME, POPS REMAIN UNMENTIONABLE
FOR MOST OF THE AREAS EAST OF THE MOUNTAINS WITH SLIGHT CHANCE (15-
25%) DURING THE AFTERNOON ON FRIDAY AND SATURDAY. WITH THIS TIME OF
YEAR, A STRAY SHOWER ESPECIALLY OVER THE MOUNTAINS GIVEN THE DAYTIME
HEATING IS POSSIBLE, BUT CONFIDENCE IS VERY LOW GIVEN THE AMOUNT OF
SUBSIDENCE ALOFT. BY SATURDAY, THERE IS MUCH DISAGREEMENT IN THE
MODELS FOR WHATEVER IS ATTEMPTING TO FORM ALONG THE CAROLINA COAST.
THE GFS SHOWS A CLASSIC FUJIWHARA EFFECT AS IT FORMS TWO WEAK LOWS
FIGHTING FOR SURVIVAL AROUND EACH OTHER. EITHER WAY, THE MODELS DO
AGREE THAT THE HIGH PRESSURE OFF TO THE NORTH REMAINS STUBBORNLY IN
PLACE OVER THE CWA AND WARDS AWAY THE PRECIP CHANCES. SO, NOTHING TO
SWEAT ABOUT FOR THE WEEKEND. AS FOR TEMPERATURES, EXPECT THE LOW 90S
WITH THE HEAT INDEX PEAKING A DEGREE OR TWO HIGHER FROM THE LOWER
DEWPOINTS.
LONG TERM /SUNDAY THROUGH WEDNESDAY/
AS OF 120 AM THURSDAY: CLOSING OUT THE END OF THE HOLIDAY WEEKEND
WITH MUCH OF THE SAME WEATHER PATTERN THAT IT STARTED WITH, QUIET.
GUIDANCE SLOWLY SHIFTS THE HIGH PRESSURE AT THE SURFACE OFF THE
COASTLINE TO THE NORTH THROUGH MOST OF SUNDAY, KEEPING A SLIGHT
CHANCE (15-30%) OF SHOWERS AND THUNDERSTORMS. SOME OF THE GUIDANCE
KEEPS THE AREA OF LOW PRESSURE CHURNING OFF THE COASTLINE AND SLOWLY
LIFTING IT NORTHEAST THROUGH THE END OF THE PERIOD. HOWEVER, IT
LOOKS AS THOUGH THE GENERAL PATTERN WILL KEEP THE RAIN AWAY FROM THE
CWA, AT LEAST FROM THIS SYSTEM. BY MONDAY AND ONWARD, LONG RANGE
GUIDANCE SHOWS A RETURN TO MORE TYPICAL SUMMERTIME DIURNALLY DRIVEN
SHOWERS AND THUNDERSTORM CHANCES. THE HIGHER POPS REMAIN AS USUAL
OVER THE MOUNTAIN AREAS. MEANWHILE, TOWARD THE END OF THE PERIOD,
GUIDANCE DOES PAINT A PICTURE OF AN AMPLIFYING RIDGE OUT WEST. IN
RESPONSE, A DEEPENING TROUGH LOOKS TO DEVELOP ACROSS THE EASTERN
PORTION OF THE CONUS, BLOCKING THE POTENTIAL HEAT DOME OUT WEST FROM
MOVING OVERHEAD, AT LEAST FOR THIS FORECAST PERIOD. AFTER MONDAY,
SOUTHERLY SURFACE MOISTURE ADVECTION RETURNS AND INCREASES THE
DEWPOINTS. CURRENTLY, GUIDANCE SHOWS POCKETS OF 100+ HEAT INDEX IN
THE SOUTHERN ZONES, INCLUDING CHARLOTTE BY TUESDAY ONWARD.
TEMPERATURES THROUGH THE PERIOD LOOK TO SLOWLY INCREASE INTO NEXT
WEEK, BUT REMAIN RELATIVELY TYPICAL FOR SUMMERTIME.
AVIATION /06Z THURSDAY THROUGH MONDAY/
AT KCLT AND ELSEWHERE: ISOLATED CONVECTION HAS DEVELOPED IN
THE VICINITY OF A WEAK FRONT ACROSS THE PIEDMONT EARLY THIS
MORNING. MOST OF THIS IS EXPECTED TO IMPACT AREAS E=>S OF THE TAF
SITES, BUT THERE IS A NON-ZERO CHANCE OF AN OVERNIGHT SHOWER OR
STORM...PRIMARILY AT KCLT AND THE UPSTATE SC TERMINALS. OTHERWISE,
VFR CONDITIONS ARE FORECAST THROUGH THE PERIOD. LOW STRATUS IS
EXPECTED TO DEVELOP AROUND THE PERIPHERY OF THE TERMINAL FORECAST
AREA LATER THIS MORNING...AND IT'S WITHIN THE REALM OF POSSIBILITY
THAT SOME OF THIS COULD DEVELOP CLOSE TO KCLT...ENOUGH TO WARRANT
A TEMPO FOR SCT006 THERE BETWEEN 10-12Z. OTHERWISE, PATCHY FOG/LOW
STRATUS IS EXPECTED ALONG SOME LAKES AND RIVERS/MOUNTAIN VALLEYS,
BUT THIS IS UNLIKELY TO AFFECT ANY TAF SITES. DRIER/LESS UNSTABLE
AIR IS EXPECTED LATER TODAY, WHICH WILL LIMIT THE CONVECTIVE
COVERAGE TO "SPARSE-AT-MOST." THUS, NO NEED TO INCLUDE ANY
CONVECTIVE MENTION IN THE FORECAST. GENERAL LIGHT AND VARIABLE
WINDS EARLY IN THE PERIOD ARE EXPECTED TO BECOME MORE DECIDEDLY
LIGHT NE LATER THIS MORNING.
OUTLOOK: DIURNAL CONVECTION IS EXPECTED TO BE INHIBITED INTO
THE WEEKEND, WITH AT MOST ISOLATED ACTIVITY EXPECTED THROUGH
SATURDAY. CONVECTIVE COVERAGE IS EXPECTED TO RETURN TO LEVELS MORE
TYPICAL OF EARLY SUMMER SUNDAY/MONDAY. FOG AND/OR LOW STRATUS
POSSIBLE EACH MORNING, MAINLY IN THE USUAL MOUNTAIN VALLEYS,
AS WELL AS NEAR LAKES AND RIVERS.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
SYNOPSIS...CP
NEAR TERM...JDL
SHORT TERM...CP
LONG TERM...CP
AVIATION...JDL
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