025
FXUS62 KGSP 260624
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
224 AM EDT TUE MAY 26 2026
WHAT HAS CHANGED
FORECAST WAS UPDATED TO REFLECT THE RECENT 06Z TAF ISSUANCE.
HIGH TEMPERATURES WERE LOWERED SLIGHTLY FOR TUESDAY BASED ON
CURRENT CONDITIONS AND RECENT MODEL TRENDS.
KEY MESSAGES
1. MOSTLY QUIET CONDITIONS CONTINUE THROUGH TUESDAY MORNING,
ALTHOUGH SEVERAL FLOOD PRODUCTS REMAIN IN PLACE FOR THE NEXT FEW
HOURS DUE TO PREVIOUS RAINFALL. WIDESPREAD SHOWERS AND STORMS
ARE EXPECTED TO REDEVELOP ON TUESDAY AFTERNOON, PRESENTING BOTH
A LOW-END SEVERE THREAT AND A LOW-END HYDRO THREAT.
2. DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS CONTINUE INTO THE
WEEKEND. DRIER CONDITIONS MAY BRIEFLY RETURN ON FRIDAY, BUT THERE
IS NOT A SIGNAL FOR MORE ROBUST DRYING UNTIL AT LEAST SUNDAY.
DISCUSSION
KEY MESSAGE 1: MOSTLY QUIET CONDITIONS CONTINUE THROUGH TUESDAY
MORNING, ALTHOUGH SEVERAL FLOOD PRODUCTS REMAIN IN PLACE FOR THE
NEXT FEW HOURS DUE TO PREVIOUS RAINFALL. WIDESPREAD SHOWERS AND
STORMS ARE EXPECTED TO REDEVELOP ON TUESDAY AFTERNOON, PRESENTING
BOTH A LOW-END SEVERE THREAT AND A LOW-END HYDRO THREAT.
THE FORECAST AREA IS NOW MOSTLY CLEAR OF SHOWERS, AS THE UPPER
VORT LOBE AND ASSOCIATED STRONGER FORCING HAVE SHIFTED INTO THE
NC PIEDMONT. WITH WHAT FEW SHOWERS REMAIN, RATES HAVE DROPPED
SIGNIFICANTLY, AND AREN'T EXPECTED TO POSE MUCH OF AN ISSUE THE REST
OF THE NIGHT. THAT SAID, WE STILL HAVE SEVERAL FLOOD ADVISORIES
AND A LONE FLASH FLOOD WARNING IN EFFECT ACROSS THE NC BLUE RIDGE
ESCARPMENT, WHERE STREAMFLOWS REMAIN ELEVATED, AND SOME LOW-LYING
AREAS ARE INUNDATED WITH PREVIOUS RAINFALL. WILL CONTINUE TO
MONITOR THESE PRODUCTS THROUGH THE COURSE OF TONIGHT, BUT BASED ON
CURRENT TRENDS, THE WORST HAS PASSED AND THINGS SHOULD IMPROVE FROM
HERE ON OUT. ONE WRINKLE IS THE TREND IN MANY OF THE 00Z CAMS,
AS WELL AS RECENT RAP CYCLES, TOWARD A BRIEF REBOUND IN UPGLIDE
ACROSS THE SMOKIES AND BALSAMS AFTER 5AM, WHICH, IF IT CAME TO PASS,
WOULD MANIFEST AS A FEW LIGHT SHOWERS THERE. QPF RESPONSE APPEARS
TO BE ON THE ORDER OF A FEW HUNDREDTHS OF AN INCH, AND GUIDANCE
DOESN'T SUGGEST EVEN THESE LIGHT SHOWERS WILL IMPACT AREAS THAT WERE
HIT MOST HEAVILY BY THIS EVENING'S RAINFALL, SO SUCH A SCENARIO
SHOULDN'T CAUSE SIGNIFICANTY IMPACTS. LIKE THE LAST FEW NIGHTS,
THE POTENTIAL FOR PATCHY DENSE FOG ALSO EXISTS THROUGH DAYBREAK,
BUT THERE'S NOT A STRONG SIGNAL FOR MORE WIDESPREAD ISSUES THAT
WOULD PROMPT ANY DENSE FOG PRODUCTS TO BE ISSUED; RATHER, DENSE
FOG IS EXPECTED TO BE MORE ISOLATED IN NATURE AND CONFINED TO
THOSE AREAS WHICH RECEIVED THE MOST RAINFALL OVER THE LAST 12 HOURS.
WE CAN EXPECT A BRIEF PERIOD OF QUIET CONDITIONS EARLY TUESDAY.
WHATEVER WEAK, SHALLOW IN SITU WEDGE IS IN PLACE BY DAWN WILL
GRADUALLY MIX OUT THROUGH LATE MORNING. THE LULL WON'T LAST LONG,
HOWEVER. HI-RES GUIDANCE RAPIDLY DESTABILIZES MOST OF THE DEEP
SOUTH, DEPICTING WIDESPREAD CONVECTIVE INITIATION THERE AS EARLY
AS 11AM...AND ALL THAT CONVECTION WILL GRADUALLY ARRIVE IN THE
UPSTATE THROUGH EARLY AFTERNOON, WITH MOST OF THE 00Z HREF MEMBERS
FEATURING WIDESPREAD SHOWERS AND EMBEDDED THUNDER ACROSS THE REGION
THROUGHOUT THE AFTERNOON AND EARLY EVENING. IT'S INCREASINGLY
LOOKING LIKE THE SEVERE THREAT WILL BE NONZERO; THE HRRR AS WELL
AS MOST OF THE CAMS FEATURE A PLUME OF SOME 1500-2000 J/KG SBCAPE
ACROSS THE AREA IN AN ENVIRONMENT OF 20-25KTS OF DEEP LAYER SHEAR.
IT'S BY NO MEANS A SLAM DUNK, BUT A COUPLE OF STRONG TO SEVERE
STORMS ARE WELL WITHIN REASON. ABOUT THE ONLY THING THEY HAVE
GOING AGAINST THEM IS THE LACK OF ANY STRONG FORCING MECHANISM
AND THUS FAIRLY WEAK MID-LEVEL LAPSE RATES THAT WILL RESULT IN
UPDRAFTS WHICH ARE TALLER, BUT WEAKER.
MEANWHILE, THE ENVIRONMENT CONTINUES TO FEATURE 1.75-2.0" PWS AND
VERY WARM, VERY MOIST PROFILES. ANY DEEPER SHOWERS AND STORMS THAT
DEVELOP COULD PRODUCE LOCALLY HEAVY RAINFALL, AND GIVEN ANTECEDENT
CONDITIONS, SOME LOCATIONS MAY NOT TAKE LONG TO REALIZE AN ISOLATED
NUISANCE FLOOD RISK, PERHAPS EVEN A LOW-END FLASH FLOOD. INDEED,
WHILE THE 00Z HREF DEPICTS GENERALLY LESS-IMPRESSIVE QPF RESPONSE
ACROSS THE AREA THAN IT DID FOR MONDAY, IT CONTINUES TO KEY ON A
CORRIDOR ACROSS THE WESTERN TWO-THIRDS OF THE UPSTATE RECEIVING
ANOTHER LOCALIZED 1.5+ INCHES THROUGH THE AFTERNOON.
KEY MESSAGE 2: DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS CONTINUE
INTO THE WEEKEND. DRIER CONDITIONS MAY BRIEFLY RETURN ON FRIDAY,
BUT THERE IS NOT A SIGNAL FOR MORE ROBUST DRYING UNTIL AT LEAST
SUNDAY.
BY WEDNESDAY, LONG-RANGE GUIDANCE BEGINS TO DEPICT A SUBTLE PATTERN
SHIFT, WITH SLIGHT HEIGHT RISES EARLY IN THE DAY AND A MORE
WSW DIRECTION TO LOW-LEVEL FLOW. THE RESULT IS MORE OF A DEEP
SOUTH MOISTURE FETCH FROM THAT POINT FORWARD, WITH TRAJECTORIES
CROSSING THE LOWER TENNESSEE VALLEY RATHER THAN ADVECTING MOISTURE
TO US DIRECTLY FROM THE GULF. WITH NO MORE SHORTWAVES FEATURED IN
SYNOPTIC GUIDANCE, LOW-LEVEL UPGLIDE TENDS TO FALTER IN MOST OF THE
ENSEMBLE OUTPUT...AND SO THE CAMS THAT GO OUT THAT FAR (AS WELL
AS THE OPERATIONAL GUIDANCE) FEATURE CONSIDERABLY LOWER COVERAGE
OF AFTERNOON SHOWERS ON WEDNESDAY AFTERNOON...WITH ANYTHING MORE
THAN ISOLATED ACTIVITY CONFINED TO THE APPALACHIANS. THAT SAID,
THERE DOES APPEAR TO BE POTENTIAL FOR ANOTHER LOW-END SEVERE
RISK ON WEDNESDAY AFTERNOON: HEIGHT FALLS OVER THE OHIO VALLEY
AND MID-ATLANTIC WILL RESULT IN AN AREA OF CONFLUENT FLOW ALOFT
THAT'LL ACTUALLY STRENGTHEN THE 500MB WIND, SO WHATEVER CONVECTION
DOES DEVELOP WILL DO SO IN AN ENVIRONMENT OF MODERATELY-BETTER DEEP
LAYER SHEAR THAN WE'VE HAD THE LAST SEVERAL FEW DAYS (AND TUESDAY).
THE REMAINDER OF THE WEEK REMAINS SOMEWHAT OF A QUESTION MARK.
LREF MEMBERS ARE TENDING STRONGLY TOWARD A SCENARIO WHERE A WEAK
BACKDOOR COLD FRONT ARRIVES SOMETIME THURSDAY...LIKELY TOO LATE IN
THE DAY TO PREVENT A BAND OF FRONTALLY-FOCUSED SHOWERS AND STORMS
FROM CROSSING THE AREA THAT AFTERNOON...AND BRIEFLY USHERING IN SOME
DRIER AIR. HOWEVER, THAT FRONT IS VARIOUSLY DEPICTED STALLING IN
OR JUST SOUTH OF THE UPSTATE, THEN ACTING AS A FOCUS FOR RENEWED
ISENTROPIC ASCENT, POSSIBLY EVEN ANOTHER HYBRID CAD EVENT, AS
THE PARENT HIGH MOVES OFF THE NEW ENGLAND COAST AND ANOTHER UPPER
TROUGH REACTIVATES THE BOUNDARY. THAT MEANS - YOU GUESSED IT -
MORE RAIN FOR FRIDAY NIGHT AND SATURDAY.
THERE REMAINS VERY HIGH UNCERTAINTY FOR THE REST OF THE WEEKEND
AND EARLY NEXT WEEK. THERE ARE REALLY TWO CAMPS AMONG LONG-RANGE
ENSEMBLES: ONE IN WHICH WE GET A STRONG COLD BACKDOOR COLD
FRONT SUNDAY NIGHT, USHERING IN A DRY CP AIR MASS THAT PERSISTS
THROUGH THE END OF D7, AND ANOTHER IN WHICH WE GET A MUCH WEAKER
BACKDOOR COLD FRONT AND ONLY MODEST, SHORT-LIVED DRYING AT BEST.
UNFORTUNATELY, THE STRONGER/DRIER SCENARIO IS CURRENTLY THE
LESS-FAVORED AMONG ENSEMBLES...BUT AT THIS TIME RANGE AND WITH HOW
UNSETTLED THE ATMOSPHERE HAS BEEN, THERE'S REALLY NO CONFIDENCE
TO BE HAD.
AVIATION /06Z TUESDAY THROUGH SATURDAY/
AT KCLT AND ELSEWHERE: CONVECTION HAS MOSTLY EXITED THE AREA
TONIGHT, WITH SOME LINGERING SHOWERS NORTH OF I-20 ON THE EXTREME
SOUTHERN FRINGE OF THE TERMINAL FORECAST AREA...BUT OTHERWISE JUST
SOME PATCHY DRIZZLE. STATISTICAL AND HI-RES GUIDANCE CONTINUES TO
FEATURE IFR TO LIFR CEILINGS DEVELOPING AGAINT TONIGHT - AND INDEED
THEY'VE BEGUN TO IN A FEW PLACES, BUT MUCH LESS WIDESPREAD AND
WITH MUCH LESS CONSISTENCY THAN ON PREVIOUS NIGHTS. NONETHELESS,
GIVEN THE AMOUNT OF RAIN THAT MUCH OF THE AREA HAS RECEIVED,
AND THE REDEVELOPMENT OF A VERY WEAK, VERY SHALLOW IN SITU WEDGE,
MOST OF THE AREA IS AT LEAST UNDER THE GUN FOR INTERMITTENT LOWERED
RESTRICTIONS THROUGH DAYBREAK. AN ISOLATED SHOWER OR TWO COULD
ALSO CROP UP ANYWHERE WITH LITTLE WARNING.
CONDITIONS SHOULD IMPROVE TO VFR IN MOST LOCATIONS BY LATE TUESDAY
MORNING. AFTERNOON CONVECTION WILL AGAIN DEVELOP ACROSS THE ENTIRE
AREA, WITH SHRA AND EMBEDDED TSRA POSSIBLE AT ALL SIX TAF SITES.
CONFIDENCE IS LIMITED ON TUESDAY NIGHT'S FORECAST, AS RESTRICTIONS
WILL BE HEAVILY DEPENDENT ON THE EVOLUTION OF AFTERNOON CONVECTION.
OUTLOOK: THE PATTERN REMAINS UNSETTLED THROUGH THE WORKWEEK WITH
AT LEAST SCATTERED DIURNAL CONVECTION EXPECTED EACH DAY (POSSIBLY
PERSISTING INTO THE OVERNIGHT HOURS) AND LOWERED VISIBILITY AND
CEILINGS FORECAST EACH NIGHT.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
MPR
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