085
FXUS62 KGSP 011759
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
159 PM EDT TUE JUL 1 2025
SYNOPSIS
A COLD FRONT CROSSES THE MOUNTAINS TONIGHT THEN BECOMING
STATIONARY ACROSS GEORGIA AND THE CAROLINAS CONTINUING THE CHANCE OF
SHOWERS AND STORMS MAINLY FOR THE PIEDMONT ON WEDNESDAY. ANOTHER
COLD FRONT DROPS SOUTH FROM THE GREAT LAKES ON THURSDAY WITH DRIER
WEATHER FOR THE INDEPENDENCE DAY HOLIDAY WEEKEND. TEMPERATURES
REMAIN TYPICAL FOR THE SUMMERTIME SEASON THROUGH THE BEGINNING OF
NEXT WEEK.
NEAR TERM /THROUGH WEDNESDAY/
AS OF 155 PM: AN UPPER TROUGH AND COLD FRONT MOVE INTO THE AREA
TONIGHT AND STALL OR ONLY SLOWLY MOVE SOUTH OF THE AREA BY
WEDNESDAY. CONVECTION ALREADY ONGOING ACROSS THE AREA AND WILL
BECOME MORE WIDESPREAD THAN THE PAST FEW DAYS. MESOANALYSIS SHOWS
THE ATMOS HAS BECOME VERY UNSTABLE DESPITE ONLY MODERATE TO WEAK MID
LEVEL LAPSE RATES. BULK SHEAR, WHILE HIGHER THAN THE PAST FEW DAYS,
REMAINS LESS THEN 20 KTS, AND DCAPE VALUES ARE MODERATE ACROSS
PORTIONS OF THE AREA. ALL THIS TO SAY THAT ISOLATED SEVERE
DOWNBURSTS WILL BE POSSIBLE WHERE STORMS CAN GROW TALL ENOUGH, BUT
THERE COULD BE SOME WEAK ORGANIZATION GIVEN THE SLIGHTLY STRONGER
SHEAR. PW VALUES REMAIN VERY HIGH AS WELL. ALTHOUGH STORMS WILL HAVE
MORE MOVEMENT THAN THE PAST FEW DAYS, LOCALLY EXCESSIVE RAINFALL IS
POSSIBLE GIVEN THE GREATER STORM COVERAGE AND THE POTENTIAL FOR
TRAINING AND BACK-BUILDING CELLS. CONVECTION DIMINISHES BY LATE
EVENING OR EARLY OVERNIGHT, BUT ISOLATED SHOWERS COULD CONTINUE. LOW
CLOUDS AND PATCHY FOG EXPECTED ONCE AGAIN BY MORNING. LOWS WILL BE A
LITTLE ABOVE NORMAL.
SCATTERED TO NUMEROUS CONVECTION IS EXPECTED TO DEVELOP ON WEDNESDAY
WITH THE STALLED OR SLOWLY MOVING TROUGH/FRONT. HOWEVER, BETTER
COVERAGE FLIPS FROM THE PAST FEW DAYS AND WILL BE GREATER ALONG THE
I-77 CORRIDOR BECOMING MORE SCATTERED ACROSS THE MOUNTAINS. AT LEAST
MODERATE INSTABILITY AND AROUND 20 KTS OF BULK SHEAR WILL COMBINE
WITH A REBOUND IN DCAPE AND SFC DELTA THETA-E TO CREATE THE
POTENTIAL FOR AN ISOLATED DAMAGING DOWNBURST. HIGHER PW VALUES ARE
SHUNTED OFF TO THE EAST AND FASTER MOVING CELLS WILL LIMIT HEAVY
RAIN POTENTIAL. HIGHS WILL BE A COUPLE OF DEGREES BELOW NORMAL.
SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/
AS OF 100 PM TUESDAY: AN UPPER TROUGH AXIS WILL EXIT OFF THE EAST
COAST THURSDAY, AS A LARGE RIDGE BUILDS IN ACROSS THE CENTER OF
THE CONUS. A COLD FRONT SHOULD FINISH PUSHING THRU THE AREA,
WITH LINGERING SHOWERS AND STORMS POSSIBLE WEDNESDAY EVENING
IN THE SOUTHEAST PART OF THE FORECAST AREA. POPS SHOULD TAPER
OFF BY DAYBREAK THURSDAY. WITH THE RIDGE BUILDING IN AND DRY AIR
ADVECTING IN FROM THE NW, THURSDAY AND FRIDAY (INDEPENDENCE DAY)
LOOK DRY. CANNOT RULE OUT A STRAY SHOWER OR GENERAL TSTM ALONG
SOME OF THE HIGHEST RIDGETOPS OF THE NC MOUNTAINS, BUT OTHERWISE
SHOULD BE DRY. TEMPS WILL WARM TO SLIGHTLY ABOVE NORMAL, WITH
HIGHS MAINLY IN THE LOWER TO MID 90S IN THE PIEDMONT AND MID TO
UPPER 80S IN THE LOWER MOUNTAIN VALLEYS. LOWS IN 60S MOUNTAINS
AND UPPER 60S TO LOWER 70S PIEDMONT. THE DEWPTS ARE EXPECTED TO
MIX OUT ENOUGH TO KEEP HEAT INDICES CLOSE TO THE AMBIENT TEMPS.
LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/
AS OF 130 PM TUESDAY: RELATIVELY DRY WEATHER CONTINUES INTO THE
WEEKEND, AS AN UPPER RIDGE SLIDES FROM THE MID-MS VALLEY EAST
TO THE MID-ATLANTIC. THIS WILL KEEP THE FORECAST AREA FAIRLY
SUPPRESSED. BUT WITH STRONG MID-SUMMER HEATING EACH DAY, A GRADUAL
INCREASE IN MAINLY MOUNTAIN CONVECTION IS EXPECTED SATURDAY
THRU MONDAY. THE MEDIUM RANGE GUIDANCE IS BECOMING A LITTLE MORE
BULLISH ON DEVELOPING A WEAK TROPICAL LOW ALONG A STALLED FRONTAL
BOUNDARY INVOF FL OVER THE WEEKEND. THIS DISTURBANCE IS LIKELY
TO REMAIN SHUNTED SOUTH OF THE FORECAST AREA, BUT MAY DRIFT NE
INTO THE ATLANTIC. THERE IS A LOT OF UNCERTAINTY ON THAT, AS IT
DEPENDS ON EXACTLY WHERE ALONG THE FRONT IT DEVELOPS AND HOW LONG
THE UPPER RIDGE CAN HOLD ON OVER THE MID-ATLANTIC. THE RIDGE IS
EXPECTED TO WEAKEN/SHIFT EAST LATE IN THE WEEKEND THRU EARLY NEXT
WEEK, AS SHORTWAVE ENERGY CARVES A FLAT TROUGH OVER THE UPPER
MIDWEST. OVERALL, THIS SHOULD ALLOW FOR A RETURN TO NEAR-CLIMO
DIURNAL POPS BY NEXT TUESDAY. TEMPS WILL CONTINUE TO BE SLIGHTLY
ABOVE NORMAL THRU THE PERIOD.
AVIATION /18Z TUESDAY THROUGH SUNDAY/
AT KCLT AND ELSEWHERE: CONVECTION GETTING STARTED ACROSS THE AREA
AND SHOULD BECOME MORE WIDESPREAD THAN THE PAST FEW DAYS. HAVE
INCLUDED TEMPOS AND PROB30S, BASED ON BEST TIMING CHANCES, THROUGH
THE AFTERNOON INTO THE EVENING. CAN'T RULE OUT SOME VARIABLY GUSTY
WINDS WITH ANY STORM THAT MOVES OVER AN AIRFIELD, OTHERWISE S TO SW
WIND AROUND 10 KTS EXPECTED. CONVECTION ENDS BY LATE EVENING OR
EARLY OVERNIGHT, BUT AN ISOLATED SHOWER IS POSSIBLE. THE MAIN
OVERNIGHT CONCERN IS AT LEAST MVFR CIGS. HAVE INCLUDED IFR CIGS
WHERE CHANCE IS HIGHEST AND SCT IFR TO SHOW THE POTENTIAL ELSEWHERE.
MVFR FOG LIKELY AS WELL WITH IFR POSSIBLE. LIGHT AND VARIABLE WINDS
OVERNIGHT AND INTO THE MORNING. VSBY SHOULD IMPROVE RELATIVELY
QUICKLY DURING THE MORNING WITH A SLOW IMPROVEMENT TO VFR BY LATE
MORNING OR EARLY AFTERNOON. AT LEAST SCT CONVECTION EXPECTED WED
AFTERNOON BUT NO MENTION AT THIS TIME DUE TO TAF RULES.
OUTLOOK: CONVECTION CONTINUES WED EVENING. DRIER AIR MOVING IN
THURSDAY IS EXPECTED TO INHIBIT DIURNAL CONVECTION INTO THE WEEKEND,
WITH AT MOST ISOLATED ACTIVITY EXPECTED EACH DAY. FOG AND/OR LOW
STRATUS POSSIBLE EACH MORNING IN THE USUAL MOUNTAIN VALLEYS, AS WELL
AS NEAR LAKES AND RIVERS, AND WHERE SIGNIFICANT RAIN FELL THE DAY
BEFORE.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
SYNOPSIS...DEO
NEAR TERM...RWH
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...RWH
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