893
FXUS62 KGSP 072219
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
619 PM EDT WED MAY 7 2025
SYNOPSIS
A STATIONARY FRONT LOCATED JUST SOUTH OF OUR AREA WILL BE THE FOCUS
FOR ON AND OFF CHANCES OF RAIN THROUGH THE FIRST HALF OF NEXT WEEK.
TEMPERATURES WILL BE BELOW NORMAL THIS WEEKEND THEN WARM UP TO NEAR
NORMAL BY THE MIDDLE OF NEXT WEEK.
NEAR TERM /THROUGH THURSDAY/
AS OF 615 PM EDT WEDNESDAY: ALTHOUGH THICK CLOUD COVER REMAINS
OVERHEAD THIS EVENING, DRIER CONDITIONS HAVE RETURN FOR MOST OF THE
FORECAST AREA. HOWEVER, A FEW AREAS OF VERY LIGHT RAIN CONTINUE
PUSHING EAST OF I-77. THUS, LOWERED POPS TO SLIGHT CHANCE THROUGH
00Z. MAIN CHANGES NEEDED THIS EVENING WAS TWEAKING THE POPS AND
THUNDER CHANCES THOUGH THE NEAR TERM BASED ON THE 18Z CAMS. NO OTHER
MAJOR CHANGES WERE NEEDED AS THE FORECAST REMAINS ON TRACK.
CLOUDS WILL STICK AROUND THROUGH THE OVERNIGHT PERIOD AND 850MB FLOW
OUT OF THE WEST-NORTHWEST INDICATES BRIEF DRYING WILL PERSIST
THROUGH LATE THIS EVENING DUE TO WEAK DOWNSLOPE FLOW. GUIDANCE
CONTINUES TO SUPPORT THE IDEA OF LOW STRATUS AND PATCHY FOG
DEVELOPING, ROUGHLY ACROSS THE WESTERN HALF OF THE FORECAST AREA.
ANOTHER AREA OF WEAK MOISTURE TRANSPORT AND UPPER DIVERGENCE FROM A
JETLET PASSING ACROSS THE CFWA AS THE CLOSED LOW PHASES WITH THE JET
STREAK THAT'S STRETCHED FROM THE SOUTHERN PLAINS THROUGH THE MID-
ATLANTIC, TURNING MORE INTO AN ELONGATED TROUGH. IN THIS CASE,
ANOTHER ROUND OF SHOWERS AND MAYBE AN ISOLATED THUNDERSTORM OR TWO
COULD DEVELOP OVERNIGHT, WITH THE BEST CHANCE OVER THE SOUTHWESTERN
THIRD OF THE CFWA. EXTENSIVE CLOUD COVER AND POSSIBLE CONVECTION
WILL LEAD TO OVERNIGHT LOWS RUNNING UP TO 5 DEGREES ABOVE NORMAL.
THE ELONGATED TROUGH WILL ENCROACH THE CFWA ON THURSDAY AS THE
ATTENDANT COLD FRONT DRAPED FROM THE MID-MS VALLEY THROUGH THE
NORTHEASTERN CONUS GRADUALLY DROPS SOUTHWARD. THE BETTER SYNOPTIC
FORCING WILL REACH THE CFWA BY PEAK HEATING THURSDAY. IN THE
PRESENCE OF THE BOUNDARY AND TROUGH, 30-40 KTS OF DEEP LAYER SHEAR
ARE EXPECTED TO GO ALONG WITH 1000-2000+ J/KG OF MLCAPE. CAMS
SUPPORT THE IDEA OF THE CONVECTION INITIATING ACROSS THE HIGHER
TERRAIN BEFORE GROWING UPSCALE AS THE MOSTLY ORGANIZED CONVECTION
PUSHES EAST ACROSS THE NC PIEDMONT AND NORTHERN UPSTATE. THIS
HAS BEEN THE MOST CONSISTENT SIGNAL WITH LESSER PORTIONS OF THE
GUIDANCE BUILDING FURTHER SOUTH INTO THE REST OF THE CFWA. DRIER
AND MODERATELY STEEP MID- TO LOW-LEVEL LAPSE RATES WITH THE
ALLUDED THERMODYNAMICS IN PLACE SHOULD SUPPORT THE INITIAL HAZARD
BEING LARGE HAIL AND A FEW MICROBURSTS (600-1000 J/KG DCAPE)
BEFORE UPSCALE GROWTH COMMENCES AS THE CONVECTION BECOMES MORE
ORGANIZED AND SUPPORTS MORE OF A STRAIGHT-LINE DAMAGING WIND
THREAT AS THE POTENTIAL FOR AN MCS IS NOT OUT OF THE PICTURE BY THE
END OF THE FORECAST PERIOD. AS A RESULT, THE SLIGHT RISK FOR SEVERE
ACROSS THE AREA (MAINLY ALONG AND NORTH OF I-85) APPEARS WARRANTED.
THE HIGHEST POPS WILL BE IN THE NORTHERN BLUE RIDGE ESCARPMENT AND
SHIFT EAST ACROSS THE NC FOOTHILLS AND PIEDMONT. TEMPERATURES WILL
END UP ~5 DEGREES ABOVE NORMAL FOR MOST LOCATIONS AS BETTER
COMPRESSIONAL HEATING OCCURS WITH THE ENCROACHING FRONTAL BOUNDARY.
SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/
AS OF 200 PM EDT WEDNESDAY: CONVECTION, SOME POSSIBLY SEVERE, WILL
BE ONGOING AT THE START OF THE PERIOD. THE SEVERITY WILL DIMINISH BY
LATE EVENING WITH COVERAGE DIMINISHING OVERNIGHT. ANOTHER ROUND OF
SHOWERS AND SCATTERED STORMS DEVELOPS DURING THE DAY FRIDAY AS A
SHORT WAVE ROTATING AROUND AN UPPER LOW OVER THE MID ATLANTIC
CROSSES THE AREA AND A WAVE MOVES EAST ALONG THE FRONTAL BOUNDARY
STALLED TO OUR SOUTH. INSTABILITY AND SHEAR LOOK TO BE WEAKER THAN
THURSDAY, SO THE SEVERE CHANCE WILL BE MUCH LOWER, BUT NOT NON-
EXISTENT. CONVECTION DIMINISHES MUCH MORE QUICKLY FRIDAY EVENING.
GUIDANCE AGREES ON THE MID ATLANTIC UPPER LOW MOVING EAST ON
SATURDAY AS ANOTHER UPPER LOW DEVELOPS OVER THE LOWER MS RIVER
VALLEY. THEY ALSO AGREE ON HIGH PRESSURE BUILDING INTO THE AREA FROM
THE NORTH WITH SOME AMOUNT OF LOW LEVEL DRY AIR FILTERING IN. THEY
ALSO AGREE ON A WEAK, MOIST SOUTHERLY FLOW DEVELOPING OVER PART OF
THE AREA. THEY DISAGREE ON WHERE THE BOUNDARY BETWEEN THE DRIER AND
MOISTER AIR SETS UP. THEREFORE, HAVE GONE WITH THE MODEL BLEND FOR
POP, WITH HIGHER VALUES OVER THE UPSTATE, NE GA, AND THE MOUNTAINS
WEST OF ASHEVILLE. LITTLE TO NO INSTABILITY IS EXPECTED MINIMIZING
THUNDER CHANCES. THERE WILL BE SOME BRIEF, HEAVY RAINFALL IN THE
STORMS THURSDAY EVENING, BUT LIGHT TO MAYBE MODERATE QPF EXPECTED
THROUGH THE REST OF THE PERIOD. TEMPS NEAR TO A LITTLE ABOVE NORMAL
FRIDAY DROP TO AS MUCH AS 10 DEGREES BELOW NORMAL SATURDAY, WITH THE
COOLER READINGS WHERE PRECIP CHANCES ARE HIGHER.
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/
AS OF 230 PM EDT WEDNESDAY: GUIDANCE REMAINS IN AGREEMENT ON THE
OVERALL PATTERN WITH SOME DISAGREEMENT ON THE DETAILS. THE UPPER LOW
OVER THE LOWER MS RIVER VALLEY WILL DOMINATE OUR EXPECTED WEATHER AS
IT SPINS IN PLACE SUNDAY, THEN BEGINS A SLOW EASTWARD TREK THROUGH
WEDNESDAY. IF SATURDAY ENDS UP DRIER, THEN THE HYBRID CAD WAITS
UNTIL SUNDAY TO DEVELOP WHEN A BETTER LOW LEVEL MOIST SOUTHERLY FLOW
DEVELOPS BRINGING SHOWERS BACK INTO THE AREA. THE CAD HOLDS ON
MONDAY WITH A CONTINUED MOIST SOUTHERLY LOW LEVEL FLOW AND
WIDESPREAD SHOWERS. THAT SAID, THERE MAY BE SOME EROSION OF THE CAD
SOUTH OF I-85 WHICH COULD SET UP A WARM FRONTAL BOUNDARY AND SOME
THUNDERSTORMS. THE UPPER AND SURFACE LOWS REALLY START MOVING
TUESDAY KEEPING THE MOIST SOUTHERLY LOW LEVEL FLOW OVER THE AREA BUT
HELPING ERODE THE CAD AS THEY MOVE IN. WIDESPREAD SHOWERS AND SOME
THUNDERSTORMS EXPECTED AGAIN. PRECIP FINALLY COMES TO AN END FROM
WEST TO EAST TUESDAY NIGHT AS THE LOWS MOVE EAST OF THE AREA.
HOWEVER, SCATTERED SHOWERS, ESPECIALLY OVER NC, WILL BE POSSIBLE
WEDNESDAY WITH LINGERING MOISTURE. TEMPS REMAIN BELOW NORMAL SUNDAY
AND MONDAY THEN RISE A LITTLE ABOVE NORMAL BY WEDNESDAY.
AVIATION /22Z WEDNESDAY THROUGH MONDAY/
AT KCLT AND ELSEWHERE: SCATTERED -DZ/-SHRA CONTINUES TO SPREAD
ACROSS THE TERMINALS EXCEPT KHKY AND WILL REMAIN IN PLACE
THROUGH MUCH OF THE AFTERNOON BEFORE DISSIPATING. THERE ARE
ASSOCIATED MVFR CIGS, BUT HAVE REMAINED SOUTHWEST OF THE AREA,
BUT GUIDANCE CONTINUES TO PUSH THIS DECK ACROSS KAND/KGMU/KGSP
LATER IN THE AFTERNOON AND EVENING, BUT CONFIDENCE IS NOT HIGH
ENOUGH FOR A PREVAILING MENTION SO PLACED THE MENTION IN A TEMPO
GROUP. LIGHT WEST-SOUTHWESTERLY WINDS THROUGH THE EVENING BEFORE
GOING LIGHT AND VARIABLE OVERNIGHT THROUGH DAYBREAK. WITH AN
EXTENDED PERIOD OF PRECIP, CONFIDENCE IN RESTRICTIONS DURING THE
EARLY MORNING HOURS THURSDAY HAVE INCREASED SO PUT EITHER IFR
OR MVFR VSBY/CIG MENTIONS AT KAND/KAND AND CAN'T BE RULED OUT
AT KGSP/KGMU/KCLT. THERE ARE ALSO HINTS OF ADDITIONAL SHOWERS
DEVELOPING OVERNIGHT, WITH KAND THE MOST LIKELY TERMINAL TO BE
IMPACTED, WITH LOWER CONFIDENCE ELSEWHERE. ANY STRATUS OR FOG THAT
DEVELOPS IS EXPECTED TO SCATTER OUT BY MID-MORNING THURSDAY WITH
LOW-END SCT/VFR CIGS LINGERING THROUGH THE REST OF THE FORECAST
PERIOD. LIGHT WEST-SOUTHWESTERLY WINDS PICK BACK UP BY MID-MORNING
THURSDAY, WITH NORTH-NORTHWESTERLY WINDS AT KAVL. PLACED A PROB30
AT KCLT WITH SHOWERS AND THUNDERSTORMS EXPECTED TO DEVELOP THURSDAY
AFTERNOON AND EVENING. WILL LIKELY NEED A PROB30 FOR THE REST OF
THE TAF SITES DURING THE 00Z UPDATE AS THE THREAT IS MOST LIKELY
TO OCCUR AFTER 18Z THURSDAY.
OUTLOOK: AN UNSETTLED PATTERN WILL LINGER INTO THE WEEKEND WITH
CHANCES FOR SHOWERS AND ASSOCIATED RESTRICTIONS.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
SYNOPSIS...DEO
NEAR TERM...AR/CAC
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...CAC
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