271
FXUS62 KGSP 071855
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
255 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 255 PM EDT WEDNESDAY: SCATTERED SHOWERS CONTINUE TO PUSH
ACROSS THE AREA AS A WEAK WARM FRONT LIFTS NORTH OF AREA AND DPVA
SURGES OUT AHEAD OF A CLOSED UPPER LOW THAT'S CENTERED OVER THE
SOUTH-CENTRAL PLAINS. THE CLUSTER OF DPVA WILL SHIFT EAST OF THE
CFWA LATER THIS EVENING AND WILL ESSENTIALLY SHUT OFF THE FORCING
NEEDED FOR THE SHOWERS TO CONTINUE. AFTERNOON HIGHS HAVE ENDED UP A
CATEGORY OR SO BELOW NORMAL ACROSS THE SOUTHWEST HALF OF THE CFWA,
WITH LOCATIONS ON THE NORTHEAST HALF GETTING CLOSER TO NORMAL
VALUES DUE TO THE DELAY IN EXTENSIVE CLOUD COVER AND PRECIP.
CLOUDS WILL STICK AROUND THROUGH THE OVERNIGHT PERIOD, BUT 850MB
FLOW OUT OF THE WEST-NORTHWEST INDICATES SOME DRYING WILL PERSIST
THANKS TO A WEAK DOWNSLOPE COMPONENT. GUIDANCE CONTINUES TO SUPPORT
THE IDEA OF LOW STRATUS AND FOG DEVELOPING, BUT MAY ONLY REACH THE
UPPER SAVANNAH AND MAJOR MOUNTAIN VALLEYS DUE TO THE DOWNSLOPE
COMPONENT. HOWEVER, 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
A THUNDERSTORM OR TWO OVERNIGHT COULD DEVELOP, WITH THE BEST CHANCE
OVER THE SOUTHWESTERN THIRD OF THE CFWA. EXTENSIVE CLOUD COVER AND
ELEVATED POPS 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 NEWLY SITUATED
SLIGHT RISK FOR SEVERE ACROSS THE AREA (MAINLY ALONG AND NORTH
OF I-85) IS 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 /19Z 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...CAC
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...CAC
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