995
FXUS62 KGSP 261818
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
218 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 210 PM: COLD AIR DAMMING HIGH CONTINUES TO BUILD INTO THE AREA
FROM THE NORTHEAST BUT HAS STALLED ACROSS THE UPSTATE. THAT COMBINED
WITH BREAKS IN THE CLOUDS HAS ALLOWED HEATING TO TAKE PLACE ACROSS
THE NC MOUNTAINS WEST OF AVL AND THE WESTERN UPSTATE AND NE GA. THIS
HAS ALLOWED THE SBCAPE TO RISE INTO THE 500 J/KG RANGE. NO LIGHTNING
SEEN AT THIS TIME BUT PRECIP IS DEFINITELY SHOWERY AROUND THE WEDGE
BOUNDARY AND MORE RAINY/DRIZZLE INSIDE IT. EXPECT THIS DICHOTOMY TO
CONTINUE AT LEAST THROUGH THE AFTERNOON AND POSSIBLY EARLY EVENING
WITH SHOWERS AND A THUNDERSTORM OR 2 OVER THE WEST AND RAIN/DRIZZLE
TO THE EAST. THE 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. BRIEF, HEAVY RAIN IS POSSIBLE IN ANY 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. LOWS
AROUND 5 DEGREES BELOW NORMAL TONIGHT. HIGHS AROUND 20 DEGREES BELOW
NORMAL TUESDAY WITH A TYPICAL WEDGE GRADIENT.
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 /18Z 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
SHORT TERM...CP
LONG TERM...CP
AVIATION...RWH
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