796
FXUS62 KGSP 061725
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
125 PM EDT WED AUG 6 2025
SYNOPSIS
A WEDGE OF COOL AND MOIST AIR WILL LINGER THROUGH MUCH OF THE WEEK
BEFORE A POTENTIAL COASTAL LOW FINALLY DISLODGES THE WEDGE LATE
THIS WEEKEND. AFTERNOON SHOWERS AND THUNDERSTORMS WILL RETURN
AND BECOME MORE NUMEROUS EACH AFTERNOON. ALTHOUGH A WARMING
TREND IS EXPECTED TO BEGIN TODAY, BELOW NORMAL HIGH TEMPERATURES
ARE EXPECTED TO CONTINUE THROUGH THIS WEEKEND, ONLY RETURNING TO
NORMAL NEXT WEEK.
NEAR TERM /THROUGH TONIGHT/
AS OF 1131 AM WEDNESDAY: THE EASTERN CONUS REMAINS SANDWICHED
BETWEEN TWO STOUT UPPER RIDGES WITH A 600DAM H5 RIDGE OVER THE
DESERT SOUTHWEST AND A 597DAM H5 RIDGE OFF THE COAST OVER THE
ATLANTIC. BETWEEN THESE TWO FEATURES, A WEAK UPPER TROUGH IS DRAPED
DOWN THE APPALACHIANS WITH THE TROUGH AXIS SHIFTING ACROSS THE AREA
TONIGHT INTO TOMORROW. AT THE SURFACE, SPRAWLING HIGH PRESSURE WILL
CONTINUE TO DROP OUT OF SOUTHEAST CANADA AND INTO NEW ENGLAND AND
THE UPPER MID ATLANTIC. AT THE SAME TIME, A STATIONARY INVERTED
TROUGH WILL CONTINUE TO SIT JUST OFF THE CAROLINA COAST. THIS WILL
CONTINUE TO PROMOTE MODEST NORTHEAST FLOW INTO THE WESTERN CAROLINAS
AND NORTHEAST GEORGIA IN A CAD CONFIGURATION. MORNING SHOWERS,
INSTIGATED BY THE PASSING UPPER WAVE, HAVE SINCE PUSHED OUT OF THE
AREA WITH A NUMBER OF BREAKS NOTED IN CLOUD COVER, ESPECIALLY
ACROSS THE UPPER SAVANNAH VALLEY. ACROSS THE MOUNTAINS, OUTSIDE OF
THE INFLUENCE OF THE CAD, BUILDING INSTABILITY WILL SUPPORT MORE
TRADITIONAL SUMMER PULSE CONVECTION WITH ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS EXPECTED THIS AFTERNOON AND EVENING,
PRIMARILY ACROSS THE SMOKIES AND SOUTHWEST MOUNTAINS.
HEADING INTO TONIGHT AND TOMORROW, THE PATTERN WILL REMAIN
RELATIVELY UNCHANGED WITH A CONTINUED DRYING TREND ACROSS MUCH OF
THE AREA. PWATS WILL FALL BELOW 1.5" WITHIN THE DRY NORTHEAST FLOW
REGIME WITH DEEPER MOISTURE CONFINED TO THE COASTAL PLAIN.
TEMPERATURES WILL WARM BACK INTO THE UPPER 70S TO LOW 80S, BUT STILL
WELL BELOW AVERAGE FOR EARLY AUGUST. THE GREATEST RAIN CHANCES WILL
ONCE AGAIN BE OVER THE MOUNTAINS WHERE INSTABILITY WILL BE ABLE TO
BUILD OUTSIDE OF THE CAD INFLUENCE WITH MECHANICAL FORCING FROM THE
TERRAIN. A FEW SHOWERS WITHIN THE EAST/NORTHEAST FLOW MAY GRAZE FAR
EASTERN PORTIONS OF THE AREA EAST OF I-77, BUT COVERAGE WILL BE
NOTABLY LESS COMPARED TO THE LAST SEVERAL DAYS.
SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/
AS OF 1258 PM EDT WEDNESDAY...
KEY MESSAGES:
1) COLD-AIR DAMMING WEAKENS BUT REMAINS IN PLACE THROUGH THE PERIOD,
MAINTAINING BELOW-NORMAL TEMPERATURES.
2) SCATTERED AFTERNOON SHOWERS AND STORMS ARE EXPECTED.
NO MAJOR CHANGES TO THE THINKING FOR FRIDAY AND SATURDAY. BY EARLY
FRIDAY MORNING, A 1027MB SURFACE HIGH WILL BE IN PLACE OFF THE MA
COAST, CONTINUING TO DRIVE E/NE FLOW ACROSS THE MID-ATLANTIC AND
CAROLINAS...AND MAINTAINING THE INCIPIENT SURFACE RIDGE OVER THE
FORECAST AREA. THOUGH THE HIGH WILL SLOWLY WOBBLE EAST THROUGH
FRIDAY AND SATURDAY, THERE'LL BE LITTLE CHANGE TO THE LOW-LEVEL
PATTERN...AND COLD-AIR DAMMING SHOULD THEREFORE REMAIN IN PLACE
THROUGH THIS TIMEFRAME. TEMPERATURES WILL THUS REMAIN SOME 8-9
DEGREES BELOW NORMAL. ALOFT, A DRAMATICALLY-WEAKENED Z500 TROUGH
WILL PUSH EAST OF THE AREA, DRIVING THE BULK OF DEEP MOISTURE OUT OF
THE AREA AND CURTAILING LOW-LEVEL ISENTROPIC ASCENT. ALL THAT TO
SAY, WHILE CAD WILL REMAIN IN PLACE...IT WON'T BE NEARLY AS RAINY
THROUGH THE SHORT TERM. THE BULK OF ENSEMBLE GUIDANCE DEPICTS THE
WEDGE MIXING OUT AT LEAST BRIEFLY EACH AFTERNOON, EXCEPT IN THE MOST
WEDGED-IN AREAS ALONG THE NC BLUE RIDGE ESCARPMENT. SO, ISOLATED
TO SCATTERED SHOWERS AND STORMS APPEAR POSSIBLE EACH AFTERNOON;
EVEN FOR THE SHELTERED ESCARPMENT ZONES, EASTERLY UPSLOPE FLOW
COULD RESULT IN SOME RAINFALL.
LONG TERM /SUNDAY THROUGH WEDNESDAY/
AS OF 113 PM EDT WEDNESDAY...
KEY MESSAGES:
1) COLD-AIR DAMMING ENDS AFTER SUNDAY/MONDAY.
2) TEMPERATURES BEGIN WARMING UP THROUGH NEXT WEEK, RETURNING TO
NORMAL VALUES BY THE END OF THE PERIOD.
3) AFTERNOON SHOWERS AND THUNDERSTORMS RETURN EACH DAY.
THE SYNOPTIC PATTERN WILL BECOME INCREASINGLY ILL-DEFINED THROUGH
THE END OF THE WEEKEND AND EARLY NEXT WEEK, WITH SOME DEGREE OF
SUBTROPICAL RIDGING MAINTAINED ACROSS THE WESTERN ATLANTIC, AND
BROAD ENSEMBLE SUPPORT FOR A DEEPENING NORTHERN-STREAM TROUGH OVER
CENTRAL CANADA AND THE NORTHERN GREAT PLAINS. OPERATIONAL GUIDANCE
STILL SUPPORTS THE DEVELOPMENT OF A CLOSED LOW OR AT LEAST ROBUST
OPEN WAVE CHURNING UP OFF THE NC-VA COASTLINE SATURDAY NIGHT INTO
SUNDAY, LARGELY DISLODGING THE SURFACE HIGH OFF THE NEW ENGLAND
COAST...AND ALLOWING CAD TO END AT LAST.
THE REMAINDER OF THE PERIOD SHOULD TREND BACK TOWARD SEASONAL
CONDITIONS...AS TEMPERATURES SLOWLY WARM UP, AFTERNOON INSTABILITY
BECOMES GREATER EACH DAY, AND DIURNAL CONVECTION RAMPS BACK UP.
BY THE END OF THE PERIOD, NEAR-NORMAL TEMPERATURES ARE EXPECTED.
AVIATION /18Z WEDNESDAY THROUGH MONDAY/
AT KCLT AND ELSEWHERE: A MIX OF CONDITIONS EXIST ACROSS THE AREA
THIS AFTERNOON AS DRIER WEATHER GRADUALLY RETURNS TO THE REGION.
MORNING SHOWERS HAVE SINCE PUSHED OUT OF THE AREA, BUT WIDESPREAD
LOW STRATUS REMAINS AN ISSUE. IFR CEILINGS HAVE AND WILL CONTINUE TO
HANG ON AT KHKY AND KCLT WITH THE UPSTATE SC TERMINALS
(KAND/KGMU/KGSP) IMPROVING TO MVFR WITH BRIEF PERIODS OF VFR
POSSIBLE AS WELL. KAVL HAS IMPROVED TO VFR, BUT A FEW INSTANCES OF
MVFR WILL BE POSSIBLE. AFTERNOON THUNDERSTORMS WILL BE POSSIBLE
ACROSS THE MOUNTAINS, OTHERWISE THE REST OF THE AREA REMAINS DRY. BY
TONIGHT, WIDESPREAD LOW STRATUS RETURNS WITH IFR TO MVFR COMMON. A
FEW INSTANCES OF FOG WILL BE POSSIBLE AS WELL AT KAVL AND KHKY.
WINDS STAY OUT OF THE NORTHEAST AT 5-10KTS WITH A FEW SPORADIC LOW-
END GUSTS POSSIBLE.
OUTLOOK: THE WEDGE PATTERN PERSISTS OVER THE TERMINALS THROUGH THE
WORKWEEK KEEPING PERIODIC RESTRICTIONS AROUND. AFTERNOON
THUNDERSTORMS ARE POSSIBLE EACH AFTERNOON AND EVENING,
MAINLY ACROSS THE MOUNTAINS.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
SYNOPSIS...MPR
NEAR TERM...TW
SHORT TERM...MPR
LONG TERM...MPR
AVIATION...TW
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