799
FXUS62 KGSP 301731
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
131 PM EDT FRI MAY 30 2025
SYNOPSIS
A COLD FRONT WILL MOVE ACROSS THE AREA TODAY, WITH SHOWERS AND
THUNDERSTORMS DEVELOPING AHEAD OF THE BOUNDARY. STRONG TO SEVERE
THUNDERSTORMS ARE POSSIBLE LATER THIS MORNING AND AFTERNOON BEFORE
THE COLD FRONT MOVES EAST OF THE AREA BY THIS EVENING. A DRIER
AIRMASS WILL MOVE INTO THE REGION THIS WEEKEND, BUT A FEW SHOWERS
CAN'T BE RULED OUT, ESPECIALLY ACROSS THE MOUNTAINS. BELOW NORMAL
TEMPERATURES THROUGH THE WEEKEND WILL RISE TO A LITTLE ABOVE NORMAL
NEXT WEEK AS A WARM AND HUMID AIRMASS RETURNS.
NEAR TERM /THROUGH TONIGHT/
AS OF 1016 AM FRIDAY: THE FORECAST REMAINS ON TRACK THIS MORNING AS
CONVECTION BEGINS TO APPROACH THE MOUNTAINS FROM THE WEST. NO MAJOR
CHANGES WERE NEEDED.
ALL EYES THEN TURN TO THE WEST AS A LINE OF ORGANIZED CONVECTION
AHEAD OF A COLD FRONT IS EXPECTED TO MOVE INTO THE NC MOUNTAINS
AROUND NOON THEN MOVE SOUTHEAST ACROSS THE AREA THROUGH THE
AFTERNOON. THERE WILL BE PLENTY OF FORCING AS A STRONG SHORT WAVE
CROSSES THE AREA, ALONG WITH THE FRONT. STRONG BULK SHEAR IS
EXPECTED AS WELL, BUT INSTABILITY COULD BE SOMEWHAT LIMITED DUE TO
MODERATE LAPSE RATES AND MODEST HEATING WITH THE LOW CLOUDS IN PLACE
TO START THE DAY. THE CAM GUIDANCE DISAGREES ON WHETHER STORM MODE
WILL BE MORE LINEAR OR MORE DISCRETE CELLS. LOW LEVEL WINDS LOOK TO
BE LESS BACKED AS THE SURFACE LOW ALONG THE FRONT WILL BE NORTH OF
THE AREA WHICH COULD HELP KEEP STORMS MORE LINEAR OR MULTI-CELL
CLUSTERS. SHOULD THIS BE THE CASE, SEVERE MODE WOULD TREND MORE
TOWARD DAMAGING WINDS WITH ONLY ISOLATED LARGE HAIL AND TORNADOES
ASSOCIATED WITH ANY HYBRID SUPERCELLS THAT MAY DEVELOP. GIVEN ALL
THIS, THE SLIGHT RISK OF SEVERE STORMS TODAY LOOKS WELL PLACED.
OUTSIDE OF ANY STORMS, GUSTY SW WIND DEVELOPS AHEAD OF THE FRONT
TURNING W TO NW BEHIND IT. HIGHS WILL BE UP TO 5 DEGREES BELOW
NORMAL.
THE STORMS WILL HAVE MOVED EAST OF THE AREA BY EARLY EVENING WITH
CLEARING SKIES AND DIMINISHING WINDS OUTSIDE OF THE MOUNTAINS.
SCATTERED SHOWERS WILL LINGER MAINLY ACROSS THE NC NORTHERN
MOUNTAINS IN THE MOIST NW FLOW. GUSTY NW WINDS WILL REMAIN ACROSS
THE MOUNTAINS AS WELL. LOWS WILL BE AROUND 5 DEGREES BELOW NORMAL.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/
AS OF 115 PM FRIDAY...A LARGE UPPER VORTEX WILL WOBBLE EAST ACROSS
QUEBEC AND NEW ENGLAND, WITH THE ASSOCIATED TROUGH AXIS REACHING
THE EAST COAST BY EARLY SUNDAY. A PRONOUNCED SHORTWAVE WILL DIVE SE
ACROSS THE MIDWEST AND HELP SHARPEN THE LONGWAVE TROUGH OVER THE
REGION SUNDAY. A SFC FRONT WILL BE DRAPED ACROSS THE AREA FROM NW
TO SE, AND MAY BE A FOCUS FOR CONVECTION. MODELS AGREE ON AROUND
1000-1500 J/KG OF SBCAPE ACROSS THE SOUTHERN 2/3RD OF THE CWFA WITH
ABOUT 30 KT OF 0-6 KM SHEAR. THIS WILL BE MARGINAL FOR ORGANIZED
STORMS, WITH MAINLY JUST SHOWERS AND GENERAL THUNDERSTORMS EXPECTED
IN THE AFTN TO EARLY EVENING. A SHOTGUN CHC POP ACROSS THE AREA
ON THE NBM LOOKS GOOD. TEMPS WILL BE A FEW DEG BELOW NORMAL FOR
THE FIRST DAY OF JUNE, LOWS IN THE 50S TO LOWER 60S AND HIGHS IN
THE 70S TO LOWER 80S.
SLIGHTLY BELOW NORMAL TEMPS CONTINUE BEHIND THE FRONT SUNDAY NIGHT
THRU MONDAY, AS A MILD AREA OF HIGH PRESSURE SETTLES OVER THE
OHIO VALLEY TO THE MID-ATLANTIC. OVERALL, VERY PLEASANT WEATHER
EXPECTED WITH SUNNY SKIES, LIGHT WIND, AND MODEST HUMIDITY.
LONG TERM /MONDAY THROUGH FRIDAY/
AS OF 300 AM EDT FRIDAY: BROAD CYCLONIC FLOW GRADUALLY BREAKDOWNS
DOWN MONDAY INTO TUESDAY AS LONGWAVE UPPER RIDGING BUILDS IN
FROM THE WEST. SYNOPTICALLY, THE AREA OF HIGH PRESSURE WILL
SHIFT EASTWARD IN RESPONSE AND SLIP OFFSHORE. GUIDANCE DIFFER
IN HOW THIS IS HANDLED AS THE DETERMINISTIC GFS DEEPENS IT INTO
A BERMUDA HIGH AS A MID-LEVEL ANTICYCLONE DEVELOP OFFSHORE THE
CAROLINA COAST. THE ECMWF DEVELOPS A CUTOFF LOW IN THE VICINITY
OF THE MID-ATLANTIC COAST BY THE MIDDLE PART OF NEXT WEEK,
WHILE PUSHING THE SURFACE HIGH FURTHER OFFSHORE OVER THE WESTERN
ATLANTIC. GEFS/EPS ARE SOMEWHERE IN BETWEEN WITH PLACING THE UPPER
RIDGE OVER THE EASTERN-THIRD OF THE CONUS AND SHOWING THE HIGH
MOVING IN THE VICINITY OF BERMUDA. EITHER WAY, WARMER THICKNESSES
WILL RETURN TO GO ALONG WITH AN UPTICK IN BETTER MOISTURE TRANSPORT,
LEADING TO WARMER AND MORE HUMID CONDITIONS BY TUESDAY AND BEYOND,
WITH AFTERNOON HIGHS AND OVERNIGHT LOWS LIKELY TO EXCEED NORMAL
VALUES BY AT LEAST A FEW DEGREES. THERE IS SOME FORM OF CONSENSUS
AMONGST MODEL GUIDANCE OF SENDING IN A COLD FRONT FROM THE WEST
LATER WEDNESDAY INTO THURSDAY, WHILE THE UPPER RIDGE BREAKS DOWN
AND THE LOW-LEVEL RETURN FLOW INCREASES. WITHOUT MUCH SYNOPTIC
SUPPORT AND A WARM AND MOIST AIRMASS IN PLACE, GUIDANCE STRUGGLE
TO COMPLETE A FULL FROPA THROUGH THE FORECAST PERIOD AND THERE
ARE SOME SIGNS THAT THE BOUNDARY COULD STALL. IN THIS CASE, DAILY
SHOWERS AND THUNDERSTORMS LOOK TO MAKE A RETURN TO THE FORECAST BY
THURSDAY OF NEXT WEEK AND MAY LINGER INTO THE UPCOMING WEEKEND AS
THE FLOW ALOFT FLATTENS OUT AND THE BOUNDARY BECOMES MORE PARALLEL
TO THE MEAN FLOW.
AVIATION /18Z FRIDAY THROUGH WEDNESDAY/
AT KCLT AND ELSEWHERE: A NUMBER OF IMPACTS TO TERMINALS FOR THE NEXT
SEVERAL HOURS BEFORE A RETURN TO VFR AREA WIDE. A LOW STRATUS DECK
CONTINUES TO FOSTER MVFR CEILINGS AHEAD OF A LINE OF SHOWERS AND
STORMS DROPPING ACROSS THE AREA. STORMS WILL MOVE ACROSS MOST
TERMINALS OVER THE NEXT SEVERAL HOURS WITH BRIEF VISIBILITY AND
CEILING RESTRICTIONS ALONG WITH THE POTENTIAL FOR GUSTY WINDS.
STORMS SHOULD EXIT THE AREA BY 20-21Z WITH A QUICK RETURN TO VFR.
WINDS WILL BE GUSTY OUT OF THE WEST/NORTHWEST INTO THIS EVENING WITH
LIGHT WINDS OVERNIGHT. GUSTS RETURN SATURDAY MORNING AND CONTINUE
THROUGH THE END OF THE PERIOD.
OUTLOOK: SHOWERS AND A FEW THUNDERSTORMS POSSIBLE AGAIN SATURDAY AND
SUNDAY. DRY HIGH PRESSURE AND VFR CONDITIONS MONDAY AND TUESDAY.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
SYNOPSIS...CAC
NEAR TERM...RWH/TW
SHORT TERM...CAC
LONG TERM...CAC
AVIATION...TW
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