098
FXUS62 KGSP 010715
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
315 AM EDT TUE JUL 1 2025
SYNOPSIS
A COLD FRONT APPROACHES THE AREA TODAY WITH A CHANCE FOR STRONGER
THUNDERSTORMS. BEHIND THE FRONT, DRIER WEATHER RETURNS FOR THE
INDEPENDENCE DAY HOLIDAY WEEKEND. TEMPERATURES REMAIN TYPICAL FOR
THE SUMMERTIME SEASON THROUGH THE BEGINNING OF NEXT WEEK.
NEAR TERM /THROUGH TONIGHT/
AS OF 300 AM: LATEST WATER VAPOR IMAGERY DEPICTS A LONG WAVE TROUGH
EXTENDING FROM THE OZARKS THROUGH THE GREAT LAKES. THE AXIS OF
THIS TROUGH IS FORECAST TO EXTEND FROM THE SOUTHERN APPALACHIANS
THROUGH THE MID-ATLANTIC BY THE END OF THE PERIOD. AS SUCH, THE
SYNOPTIC PATTERN IS EXPECTED TO BECOME PROGRESSIVELY FAVORABLE
FOR DEVELOPMENT OF DEEP CONVECTION THROUGHOUT THE DAYLIGHT
HOURS. INCREASING HIGH AND MID-LEVEL CLOUDS WILL SOMEWHAT LIMIT
THE HEATING POTENTIAL TODAY...FORECAST TEMPS ARE EXPECTED TO TOP
OUT RIGHT AROUND NORMAL...BUT MOISTURE AND INSOLATION IS EXPECTED
TO BE SUFFICIENT TO ALLOW FOR DESTABILIZATION TO THE TUNE OF AROUND
2000 J/KG OF SBCAPE BY MID-AFTERNOON. SCATTERED DEEP CONVECTION IS
EXPECTED TO INITIALLY BEGIN FIRING ALONG THE BLUE RIDGE AS NORMAL
DURING EARLY AFTERNOON...ALTHOUGH THERMAL SURFACE TROUGH COULD ALSO
PROVIDE A FOCUS FOR ISOLATED PIEDMONT ACTIVITY THAT EARLY IN THE
DAY. WITH MEAN CLOUD-BEARING WINDS STEADILY INCREASING TO 10-15 KTS
THROUGH THE AFTERNOON, CONVECTION WILL MOVE OFF THE HIGH TERRAIN
INTO THE PIEDMONT AND FOOTHILLS DURING MID-TO-LATE AFTERNOON.
CONVECTIVE COVERAGE IS EXPECTED TO PEAK DURING THE LATE AFTERNOON
AND EVENING, AS ACTIVITY ASSOCIATED WITH WEAK SURFACE BOUNDARY
MOVES INTO THE SOUTHERN APPALACHIANS FROM THE TN VALLEY. POPS
ARE GENERALLY IN THE 70-80% RANGE ACROSS MUCH OF THE CWA
DURING THIS TIME. ISOLATED SEVERE STORMS WILL BE POSSIBLE THROUGHOUT
THE AFTERNOON AND EVENING...MAINLY OF THE PULSE VARIETY WITH THE
HIGH TERRAIN-INITIATING CONVECTION EARLIER IN THE AFTERNOON...AND
WITH ADDITIONAL PULSE CELLS BUT ALSO POSSIBLY CLUSTERING ALONG
OUTFLOWS LATER IN THE DAY AS THE SHEAR INCREASES TO AROUND 20 KTS.
DESPITE THE INCREASING CELL MOTION...THE POTENTIAL FOR LOCALLY
EXCESSIVE RAINFALL WILL ALSO EXIST UNDER VERY MOIST CONDITIONS...
PRECIPITABLE WATER VALUES AOA 1.75"...DEEP WARM CLOUD LAYERS OF OVER
12KFT, AND THE POTENTIAL FOR TRAINING CELLS AND/OR BACK-BUILDING
MULTICELLS. CONVECTION WILL BEGIN TO DIMINISH, BUT WITH SOME DEGREE
OF COVERAGE LIKELY PERSISTING THROUGH THE OVERNIGHT, AS TROUGH AXIS
AND ATTENDANT BOUNDARY SHIFT STEADILY EAST ACROSS THE CWA. MIN TEMPS
WILL BE A COUPLE OF DEGREES ABOVE NORMAL.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/
AS OF 230 AM TUESDAY: PICKING UP WEDNESDAY, A FRONTAL BOUNDARY
SHOULD BE IN THE MIDST OF PASSING THROUGH THE CWA. ALOFT, A
WEAKENING TROUGH SLIDES OFF THE COAST BRINGING LIGHT NW FLOW AND
ADVECTING DRIER AIR INTO THE AREA. ANY LINGERING PRECIP CHANCES
QUICKLY DIMINISH THROUGH THE DAY AS THE MOISTURE SUPPLY GETS CUTOFF.
CURRENTLY, GUIDANCE DROPS POPS FROM SLIGHT CHANCE (25-35%) TO
UNMENTIONABLE (<15%) BY WEDNESDAY EVENING. FROM THERE, THE REGION
STAYS UNDER THIS REINFORCING DRY AIR AND NW WINDS INTO THURSDAY.
MEANWHILE, A RIDGE BEGINS TO AMPLIFY OVER THE CENTRAL CONUS AND BY
THURSDAY NIGHT, PROGRESSES EASTWARD. SLOW HEIGHT RISES THROUGH THE
END OF THE PERIOD AS THIS HIGH PRESSURE EXPANDS. POPS REMAIN LESS
THAN 15% ON THURSDAY, KEEPING THE SHORT TERM PERIOD RELATIVELY DRY.
CNA'T RULE OUT A STRAY SHOWER OVER THE MOUNTAINS GIVEN THE TYPICAL
DAYTIME HEATING, BUT IT WILL BE DIFFICULT TO INITIATE WITH THE DRIER
AIR. AS FOR TEMPERATURES, WEDNESDAY WILL BE THE COOLEST DAY AS
WARMING REBOUNDS DUE TO THE BUILDING HIGH PRESSURE BY THURSDAY.
LONG TERM /FRIDAY THROUGH MONDAY/
AS OF 220 AM TUESDAY: BY THE INDEPENDENCE DAY HOLIDAY, GUIDANCE IS
KEEPING THE WEATHER LOOKING FAVORABLE FOR ACTIVITIES INVOLVING
FIREWORKS. LONG RANGE GUIDANCE HAS THE AREA UNDER MOSTLY HIGH
PRESSURE BY FRIDAY AND INTO THE MAJORITY OF THE WEEKEND. POPS REMAIN
LOW AND IN THE SLIGHT CHANCE RANGE (15-35%), WITH THE HIGHER CHANCES
OVER THE MOUNTAINS. LIGHT WINDS AND TEMPERATURES CLOSE TO NORMAL
THROUGH AT LEAST MONDAY. NOW, THERE IS SOME DISAGREEMENT WITH MODEL
RUNS ABOUT AN AREA OF LOW PRESSURE OVER THE GULF, BUT HOW THE HIGH
PRESSURE AMPLIFIES, SHOULD BE ENOUGH TO KEEP ANYTHING FROM REACHING
THE CWA AT THIS TIME. EITHER WAY, POPS START TO INCREASE TOWARD THE
END OF THE PERIOD WITH MORE TYPICAL SUMMERTIME SHOWERS AND
THUNDERSTORMS. TEMPERATURES THROUGH THE PERIOD LOOK TO REMAIN STEADY
AROUND CLIMO AND SHUNTS AWAY ANY CHANCE FOR EXCESSIVE HEAT.
AVIATION /07Z TUESDAY THROUGH SATURDAY/
AT KCLT AND ELSEWHERE: SPOTTY SHOWERS ARE STREAMING ACROSS THE
MOUNTAINS AND FOOTHILLS EARLY THIS MORNING, BUT THESE ARE VERY
UNLIKELY TO MAKE A DIRECT HIT ON ANY TAF SITE. THE PRIMARY IMMEDIATE
CONCERN IS THEREFORE THE POTENTIAL FOR SOME FOG AND/OR LOW STRATUS
TOWARD DAYBREAK IN THE CONTINUED VERY MOIST CONDITIONS. SIMILAR
TO MONDAY MORNING, EXPECT A BRIEF PERIOD OF IFR/LIFR CONDITIONS
AT KHKY AND KAVL CENTERED AROUND 12Z...WHICH IS HANDLED WITH
TEMPOS. THERE IS ALSO SOME HINT FROM THE LATEST GUIDANCE OF IFR
STRATUS POTENTIAL IN THE KCLT AREA LATER THIS MORNING, AND THIS
SEEMS PLAUSIBLE ENOUGH TO ADVERTISE A TEMPO FOR SCT009 THERE BETWEEN
11 AND 13Z. OTHERWISE, CONVECTION IS EXPECTED TO DEVELOP ACROSS
THE MOUNTAINS BY EARLY AFTERNOON...WITH SOME ISOLATED ACTIVITY
POSSIBLE IN OTHER AREAS DURING THAT TIME. CONVECTION WILL MOVE OFF
THE HIGH TERRAIN INTO THE PIEDMONT/FOOTHILLS FROM MID-AFTERNOON
INTO THE EVENING. ADDITIONAL CONVECTION WILL MOVER OVER THE AREA
DURING THE EVENING IN ADVANCE OF A COLD FRONT. PROB30S FOR TSRA
ARE WARRANTED AT ALL SITES THIS AFTERNOON...WITH A TRANSITION TO
CATEGORICAL -SHRA AND VCTS THIS EVENING. SW WINDS OF 5-10 KTS ARE
EXPECTED THROUGH MUCH OF THE PERIOD. CAN'T RULE OUT SOME GUSTS OF
15-20 KTS ACROSS THE PIEDMONT DURING THE AFTERNOON.
OUTLOOK: SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE
EXPECTED AGAIN WEDNESDAY AFTERNOON/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...CP
NEAR TERM...JDL
SHORT TERM...CP
LONG TERM...CP
AVIATION...JDL
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