815
FXUS62 KGSP 270613
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
213 AM EDT TUE MAY 27 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 TODAY/
AS OF 12:45 AM EDT TUESDAY: A COOL-AIR DAMMING WEDGE REMAINS IN
PLACE ACROSS THE FCST AREA AS WE HEAD INTO THE OVERNIGHT. PATCHES
OF STRATIFORM PRECIP CONTINUE TO MAKE THEIR WAY NE ACROSS OUR AREA
WITH A MUCH BROADER AREA OF PRECIP JUST NOW STARTING TO MOVE OVER
OUR FAR WESTERN ZONES. THIS ACTIVITY IS EXPECTED TO OVERSPREAD OUR
CWA THRU THE OVERNIGHT AND INTO THE MORNING AS ISENTROPIC UPGLIDE
INCREASES AND LOW-LEVEL WINDS VEER IN RESPONSE TO A WEAK LOW MOVING
UP THE WEST SIDE OF THE APPALACHIANS. THIS SET UP SHOULD HELP LOCK
IN THE WEDGE FOR TUESDAY. OTHERWISE, I REVISED THE POP TRENDS INTO
MIDDAY PER HI-RES MODEL CONSENSUS. LOWS OVERNIGHT SHOULD BE ROUGHLY
5 DEGREES BELOW NORMAL. MAINLY RAIN AND DRIZZLE WITH THE MORNING
PRECIP ACTIVITY, ALTHOUGH A FEW ISOLATED, ELEVATED THUNDERSTORMS
WILL BE POSSIBLE DURING THE AFTERNOON AS MUCAPE INCREASES. HIGHS
SHOULD REMAIN AROUND 20 DEGREES BELOW NORMAL ON TUESDAY WITH A
TYPICAL WEDGE GRADIENT WRT TEMPERATURES. AS FOR THE FLOODING POTEN-
TIAL, BRIEF, HEAVY RAIN IS POSSIBLE IN ANY THUNDERSTORM, BUT NO
SIGNIFICANT FLOODING IS EXPECTED. SOME PONDING IN LOW-LYING AREAS
IS MORE LIKELY.
SHORT TERM /TONIGHT 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 /06Z TUESDAY THROUGH SATURDAY/
AT KCLT AND ELSEWHERE: EXPECT COOL-AIR DAMMING REGIME TO KEEP
IFR CIGS AND MVFR TO IFR VISBY IN PLACE ACROSS OUR AREA FOR MOST
OF THE 06Z TAF PERIOD. MORE WIDESPREAD SHOWERS/DRIZZLE ARE EXPEC-
TED TO MOVE OVER THE AREA FROM THE WEST DURING THE FIRST FEW HRS
OF THE TAF PERIOD AND PERSIST THRU THE MORNING. I HAVE A PROB30
FOR HEAVIER SHRA AND IFR TO LIFR RESTRICTIONS AT ALL TAF SITES
FROM ROUGHLY 10 TO 16Z. PER THE LATEST CAM GUIDANCE, I EXPECT A
LULL IN PRECIP ACTIVITY/COVERAGE DURING THE AFTERNOON, HOWEVER
CIGS ARE NOT LIKELY TO IMPROVE MUCH THRU THE DAY. EXPECT ANOTHER
ROUND OF MORE WIDESPREAD PRECIP BY MID TO LATE EVENING, THAT WILL
LIKELY CONTINUE THRU THE REMAINDER OF THE TAF PERIOD. WE COULD SEE
SOME ELEVATED INSTABILITY DEVELOP AROUND THE PERIPHERY OF THE WEDGE
TODAY, BUT I THINK ANY THUNDER THEY MIGHT OCCUR IN OUR FCST AREA
WILL BE TOO ISOLATED TO MENTION IN THE TAFS. OTHERWISE, WINDS WILL
REMAIN NELY OUTSIDE THE MTNS THRU THE PERIOD WITH SOME SPORADIC
LOW-END GUSTS POSSIBLE ESPECIALLY AT THE UPSTATE TERMINALS. AT KAVL,
WINDS WILL FAVOR A SELY DIRECTION THRU THE PERIOD.
OUTLOOK: SHOWER AND THUNDERSTORM CHANCES AND ASSOCIATED RESTRICTIONS
CONTINUE THRU THE WEEK WITH DRIER CONDITIONS EXPECTED BY THE START OF
THE WEEKEND.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
SYNOPSIS...DEO
NEAR TERM...JPT/WIMBERLEY
SHORT TERM...CP
LONG TERM...CP
AVIATION...JPT
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