935
FXUS62 KGSP 262200
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
600 PM EDT MON MAY 26 2025
SYNOPSIS
COOL HIGH PRESSURE MOVING ACROSS THE GREAT LAKES AND NEW YORK WILL
CAUSE UNSEASONABLY COOL WEATHER ON TUESDAY FOR THE WESTERN CAROLINAS
AND NORTHEAST GEORGIA WITH A BRIEF WEDGE PATTERN. WIDESPREAD SHOWERS
WILL FOLLOW FROM WEST TO EAST ALONG A STATIONARY FRONT LOCATED JUST
SOUTH OF OUR AREA THROUGH MID WEEK. A SLOW MOVING WEAK COLD FRONT
WILL DRIFT ACROSS OUR REGION THURSDAY AND FRIDAY BRINGING IN DRIER
WEATHER FOR THE WEEKEND.
NEAR TERM /THROUGH TUESDAY/
AS OF 545 PM: BOUNDARY OF COLD-AIR DAMMING WEDGE SEEMS TO BE VISIBLE
ON RECENT SATELLITE LOOP WITH EDGE OF STRATOCU SHIFTING SOUTH ACROSS
THE UPSTATE, SOUTH OF THE GSP METRO, WITH CLOUDS HAVING FILLED IN
OVER HAYWOOD CO MARKING THE WESTERN EXTENT. SOME AREAS OF CLEAR SKY
ARE STILL SEEN SOUTH AND WEST OF THOSE AREAS, CHARACTERIZED BY UP
TO 1000 J/KG OF SBCAPE. NOTED A RECENT UPTICK IN SHOWER COVERAGE
WITHIN THAT UNSTABLE AIR. JUST LIGHT STRATIFORM PRECIP WITHIN THE
WEDGE, SOME OF WHICH IS TOO SHALLOW TO SEE ON RADAR. BASICALLY,
TYPICAL WEDGE IN THIS SENSE. HEADING INTO EVENING, THE SHOWERS
SHOULD WANE DIURNALLY, ALTHOUGH THE UPGLIDE-DRIVEN PRECIP WILL
TAKE SOME TIME TO RAMP UP, SO THERE MAY BE A RELATIVE LULL IN
ACTIVITY OVERALL. AS LOW-LEVEL WINDS VEER IN RESPONSE TO WEAK
LOW MOVING UP THE WEST SIDE OF THE APPALACHIANS LATER TONIGHT,
STRATIFORM PRECIP SHOULD INCREASE IN COVERAGE AND INTENSITY,
LEADING TO STRONGER WEDGE EFFECTS BY MORNING. TEMP TRENDS WERE
REVISED THRU THE OVERNIGHT, WITH EVENING TEMPS SLIGHTLY WARMER IN
PARTS OF THE UPSTATE PER HRRR WHICH IS HANDLING THE WEDGE BOUNDARY
FAIRLY WELL. LOWS AROUND 5 DEGREES BELOW NORMAL.
DAMMING HIGH SHOULD SPREAD ACROSS THE AREA OVERNIGHT AND REMAIN IN
PLACE ON TUESDAY, WITH MAINLY RAIN AND DRIZZLE FOR THE MORNING, BUT
AN ISOLATED, ELEVATED TSRA POSSIBLE DURING THE AFTERNOON. HIGHS
AROUND 20 DEGREES BELOW NORMAL TUESDAY WITH A TYPICAL WEDGE
GRADIENT.
BRIEF, HEAVY RAIN IS POSSIBLE IN ANY T-STORM. SOME MODERATE TO
POSSIBLY BRIEF, HEAVY RAIN IS POSSIBLE OVERNIGHT AS ISENTROPIC LIFT
AND UPSLOPE FLOW STRENGTHENS. NO SIGNIFICANT FLOODING IS EXPECTED,
BUT SOME PONDING IN LOW LYING AREAS IS POSSIBLE.
SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/
AS OF 140 PM MONDAY: MESSY PATTERN CONTINUES INTO THE SHORT TERM.
MOSTLY A QUASI-ZONAL PATTERN KEEPING FLOW ALOFT MOSTLY WESTERLY
THROUGH THE PERIOD. EMBEDDED IN THE FLOW ARE A SERIES OF SHORTWAVES
THAT COULD HELP TRIGGER SOME SHOWERS, BUT TRUE CONVECTION LOOKS
MINIMAL. TUESDAY NIGHT, GUIDANCE HAS SHOWERS AND A FEW RUMBLES OF
THUNDER POSSIBLE THROUGH AT LEAST WEDNESDAY MORNING. THE CAD IS ALSO
EXPECTED TO WEAKEN WEDNESDAY, BRINGING WARMER TEMPERATURES, BUT A
DECREASE IN MOISTURE. THIS SHOULD SUPPRESS MUCH OF THE RAIN CHANCES
THROUGH WEDNESDAY NIGHT. BY THURSDAY, PWATS ONCE AGAIN INCREASE AS
SURFACE WINDS TURN MORE SOUTHERLY. SOME SPLIT IN THE GUIDANCE AS THE
GFS HAS ANOTHER SHORTWAVE PASSING ACROSS THE SOUTHEAST THURSDAY,
WHICH COULD INCREASE PRECIP CHANCES ONCE AGAIN. HOWEVER, THE EURO
AND CANADIAN MODELS ARE MUCH DRIER. SO FOR THE MISALIGNMENT OF
GUIDANCE, CONFIDENCE REMAINS LOW. WINDS REMAIN LIGHT AS WELL.
DEPENDING ON HOW FAST THE CAD CAN ERODE, TEMPERATURES SHOULD REBOUND
INTO THE UPPER 70S AND LOW 80S BY THURSDAY.
LONG TERM /THURSDAY NIGHT THROUGH MONDAY/
AS OF 200 PM MONDAY: BY THURSDAY NIGHT, THE MODELS START TO DIVERGE
IN AGREEMENT WITH WHAT MIGHT HAPPEN OR NOT. THE GFS REMAINS THE
WETTER SOLUTION WITH CHURNING A LOW OVER THE GREAT LAKES AND
EXTENDING A COLD FRONT SOUTHWARD TOWARD THE SOUTHEAST BY FRIDAY.
OTHER MODEL GUIDANCE IS LESS RESPONSIVE TO THIS SCENARIO AND DRIER.
SO, THE AMOUNT OF RAIN THAT MAY OR MAY NOT COME THROUGH IS A BIT UP
IN THE AIR. ENSEMBLE GUIDANCE PUTS ABOUT A 40-50% CHANCE OF
MEASURABLE RAINFALL ACROSS THE ENTIRE CWA ON FRIDAY, AHEAD OF A
POTENTIAL COLD FRONT. SHOULD THIS OCCUR, DRIER AIR LOOKS TO RETURN
FROM THE NW FOR THE WEEKEND. WEAK HIGH PRESSURE TRIES TO BUILD BACK
INTO THE NORTH ATLANTIC REGION AND EXTEND SOUTHWARD, POTENTIALLY
KEEPING THE AREA DRY. ALL IN ALL, A POSSIBLE COLD FRONT COULD SWING
THROUGH, BRINGING WIDESPREAD SHOWERS ON FRIDAY, BUT CONFIDENCE IS
LOW AT THIS TIME. TEMPERATURES LOOK TO RISE CLOSER TO NORMAL THROUGH
NEXT WEEKEND.
AVIATION /22Z MONDAY THROUGH SATURDAY/
AT KCLT AND ELSEWHERE: COMPLICATED FORECAST TODAY AS A COLD AIR
DAMMING HIGH BUILDS IN FROM THE NORTH AS A SERIES OF UPPER WAVES
MOVE OVER THE AREA. IFR CIGS EXPANDING FROM N TO S ACROSS THE AREA
WITH VFR TO MVFR VSBY IN PATCHY RAIN AND DRIZZLE. LIFR CIGS AND IFR
VSBY AT KHKY. GENERALLY MVFR CIGS AND VFR VSBY FOR THE SC SITES TO
START BECOMING IFR CIGS AND VFR TO MVFR VSBY LATE IN THE DAY.
CONDITIONS BECOME STEADILY IFR TO LIFR DURING THE EVENING INTO THE
OVERNIGHT AS RAIN AND SHOWERS BECOME MORE WIDESPREAD. IFR TO LIFR
CONDITIONS CONTINUE TUE MORNING WITH CONTINUED RAIN AND SHOWERS. E
TO NE WIND WITH OCCASIONAL LOW END GUSTS CONTINUE THROUGH THE
PERIOD. KAVL WILL SEE LIGHTER SOUTHEASTERLY WINDS. CAN'T RULE OUT AN
ISOLATED TSRA NEAR KAVL OR KAND, BUT CHANCE TOO LOW FOR THE TAFS.
OUTLOOK: SHOWER AND THUNDERSTORM CHANCES AND ASSOCIATED
RESTRICTIONS CONTINUE THROUGH THE WEEK THEN DIMINISH ON SATURDAY.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
SYNOPSIS...DEO
NEAR TERM...RWH/WIMBERLEY
SHORT TERM...CP
LONG TERM...CP
AVIATION...RWH
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