000
FXUS62 KGSP 250641
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
241 AM EDT MON MAY 25 2026
WHAT HAS CHANGED
RAISED TONIGHT'S LOW TEMPERATURE, AND MONDAY HIGH TEMPERATURES,
SLIGHTLY TO ACCOUNT FOR RECENT TRENDS.
RAISED QPF SLIGHTLY THE FIRST HALF OF MONDAY NIGHT, CONSISTENT
WITH RECENT MODEL GUIDANCE SUGGESTING LOCALIZED HIGHER RAINFALL
TOTALS IN SOME PARTS OF THE AREA.
UPDATED THE AVIATION DISCUSSION TO REFLECT THE RECENT 06Z TAF
ISSUANCE.
KEY MESSAGES
1. RAINFALL WILL TAPER OFF THE REMAINDER OF SUNDAY NIGHT, GIVING
WAY TO ANOTHER FOGGY MORNING. PATCHY DENSE FOG IS POSSIBLE THROUGH
MONDAY MORNING. ANOTHER ROUND OF RAINFALL MAY DEVELOP LATE MONDAY
INTO MONDAY NIGHT, BUT CONFIDENCE IS LIMITED.
2. RAINY WEATHER WITH POTENTIAL FOR AFTERNOON STORMS CONTINUES
THROUGH AT LEAST WEDNESDAY. A COLD FRONT AND SOME DRIER AIR MAY
ARRIVE BY THURSDAY, BUT THE PATTERN IS HIGHLY UNCERTAIN PAST
THIS POINT.
DISCUSSION
KEY MESSAGE 1: RAINFALL WILL TAPER OFF THE REMAINDER OF SUNDAY NIGHT,
GIVING WAY TO ANOTHER FOGGY MORNING. PATCHY DENSE FOG IS POSSIBLE
THROUGH MONDAY MORNING. ANOTHER ROUND OF RAINFALL MAY DEVELOP
LATE MONDAY INTO MONDAY NIGHT, BUT CONFIDENCE IS LIMITED.
WIDESPREAD RAIN CONTINUES ACROSS THE FORECAST AREA TONIGHT AS
A 500MB SHORTWAVE, NOW LOCATED SOMEWHERE ALONG OR EAST OF I-26,
PIVOTS ACROSS THE AREA, EMBEDDED WITHIN BROADER SW UPPER FLOW.
OVER THE LAST HOUR, RAIN RATES HAVE DROPPED OFF SHARPLY AS SURFACE
INSTABILITY IS LOST AND IN SITU COLD AIR DAMMING REINTENSIFIES
IN RESPONSE TO DIABATIC COOLING FROM THE RAIN. ALTHOUGH SOME
LOCALIZED HEAVIER RATES MAY REDEVELOP OVER THE NEXT TWO TO THREE
HOURS...GENERALLY EXPECT COVERAGE AND INTENSITY OF RAIN TO CONTINUE
TO DIMINISH THROUGH THE REST OF THE OVERNIGHT, WITH ONLY PATCHY
DRIZZLE IN PLACE BY MORNING. LIKE LAST NIGHT, THE BIGGER STORY
WILL BE THE POTENTIAL FOR PATCHY DENSE FOG AND WIDESPREAD LOW
STRATUS. HOWEVER, STATISTICAL AN HI-RES GUIDANCE ARE CONSIDERABLY
LESS BULLISH WITH LOW VISIBILITIES THAN THEY WERE LAST NIGHT,
SO DON'T CURRENTLY HAVE PLANS TO ISSUE ANY DENSE FOG PRODUCTS.
WILL CONTINUE TO MONITOR CONDITIONS CLOSELY.
QUIETER CONDITIONS ARE EXPECTED FOR MOST OF MONDAY. UPPER FLOW WILL
REMAIN LARGELY UNPERTURBED WITH DEEP LAYER S/SW WINDS PERSISTING,
AND NO DISCERNIBLE VORT LOBES IN OPERATIONAL MODELS. WE CAN EXPECT
SOME DECENT INSTABILITY TO DEVELOP AS THE WEDGE MOSTLY MIXES OUT
DURING PEAK HEATING...WITH HI-RES GUIDANCE DEPICTING ON THE ORDER
OF 1500 J/KG SBCAPE ACROSS MUCH OF THE AREA. TRIGGERING WILL
BE AN ISSUE, BUT AT LEAST A HANDFUL OF SHOWERS AND STORMS MAY
DEVELOP, PARTICULARLY OVER THE MOUNTAINS. A POTENTIAL WRINKLE IN
THE FORECAST COMES FROM WHAT LOOK LIKE A SERIES OF SUBTLE SPEED
MAXXES EMBEDDED WITHIN THE UPPER FLOW DURING THE AFTERNOON PERIOD,
THOUGH NONE OF THE MODELS CAN REALLY PINPOINT WHEN THEY'LL ARRIVE,
OR EXACTLY WHERE THEY'LL BE MAXIMIZED. AS A RESULT, WHILE SHEAR
PROFILES GENERALLY LOOK TAME, THERE'S A POSSIBILITY THAT LOCALIZED
HIGHER SHEAR COULD DEVELOP BENEATH ONE OF THESE SPEED MAXIMA AND
RESULT IN AN ISOLATED STRONGER STORM DEVELOPING. AND, AS ALWAYS
IN THESE SITUATIONS, CONVECTION OCCURRING NEAR THE WEDGE BOUNDARY
COULD SEE A LOCALIZED INCREASE IN SRH, INCREASING THE SEVERE RISK.
NONETHELESS, WITH SUCH LOW COVERAGE OF AFTERNOON CONVECTION
EXPECTED, THE SEVERE RISK REMAINS LOW, IF PERHAPS NONZERO.
LATE IN THE DAY, A SECOND, MORE FOCUSED SHORTWAVE WILL EJECT OFF THE
EASTERN PERIPHERY OF AN UPPER LOW CURRENTLY CENTERED OVER THE GULF
COAST. IT'LL REACH THE CAROLINAS BY LATE EVENING, IN TURN SPURRING
ANOTHER ROUND OF STRONGER ISENTROPIC ASCENT THROUGH THE FIRST HALF
OF THE NIGHT. THE 00Z CAMS ARE REALLY STRUGGLING TO GET A HANDLE
ON THE POTENTIAL FOR THIS FEATURE, VARIOUSLY DEPICTING ANYWHERE
FROM MINIMAL COVERAGE, TO WIDESPREAD RAIN-PRODUCERS GENERATING AS
MUCH AS A HALF INCH OF RAIN IN SOME LOCATIONS BETWEEN SUNSET AND
PERHAPS 3 AM. THE 00Z HREF AND REFS GUIDANCE DON'T OFFER MUCH
CLARITY - SO CONFIDENCE REMAINS LIMITED IN HOW RAIN WILL EVOLVE
FOR MOST OF THE NIGHT. THIS ALSO MAKES THE STRATUS/FOG POTENTIAL
QUESTIONABLE, SINCE THE TREND TOWARD LOWER COVERAGE IN RECENT
GUIDANCE WOULD ALSO MEAN LESS REINFORCEMENT OF ANY LINGERING WEDGE.
KEY MESSAGE 2: RAINY WEATHER WITH POTENTIAL FOR AFTERNOON STORMS
CONTINUES THROUGH AT LEAST WEDNESDAY. A COLD FRONT AND SOME DRIER
AIR MAY ARRIVE BY THURSDAY, BUT THE PATTERN IS HIGHLY UNCERTAIN
PAST THIS POINT.
DIURNAL CONVECTION IS EXPECTED TO CONTINUE THROUGH THE FIRST HALF
OF THE WEEK AS A MOIST AND MODERATELY-UNSTABLE AIR MASS REMAINS IN
PLACE ACROSS THE AREA. THE UPPER LOW PREVIOUSLY CENTERED OVER THE
GULF COAST WILL LIFT NORTH AND MERGE INTO THE MEAN FLOW THROUGH
TUESDAY, AND THE SUBTROPICAL RIDGE WILL ACTUALLY EXPAND WESTWARD,
SUCH THAT THE SOURCE OF THESE SHORTWAVES THAT HAVE BEEN GIVING US
THE HEAVIER RAIN PERIODS WILL VANISH, AND MOISTURE FETCH WILL BECOME
SUBTLY WEAKER. STILL, MOIST PROFILES AND DIURNAL INSTABILITY WILL
MAINTAIN DAILY RAIN CHANCES THROUGH AT LEAST WEDNESDAY.
AN AREA OF HEIGHT FALLS IS DEPICTED ACROSS NEW ENGLAND AND
THE UPPER OHIO VALLEY ON THURSDAY, AND THERE'S AN INCREASINGLY
STRONG SIGNAL IN THE SYNOPTIC GUIDANCE FOR A LATE WEEK BACKDOOR
COLD FRONT ARRIVING THURSDAY OR THURSDAY NIGHT. THIS IS REALLY
STRONGLY SUPPORTED IN THE 00Z LREF...TO THE POINT THAT ALL
FOUR DOMINANT CLUSTERS DEPICT AT LEAST A WEAK FROPA DURING THIS
PERIOD...SUGGESTING THE POSSIBILITY OF SOME DRYING LATE IN THE WEEK.
GUIDANCE REALLY GOES HAYWIRE BY NEXT WEEKEND, HOWEVER. WILL WE HAVE
SUSTAINED WEAK CAA AND DRYING? ANOTHER SHORTWAVE AND ASSOCIATED
UPGLIDE OVER A STAGNANT FRONTAL BOUNDARY, REGENERATING CAD AND
PUTTING US RIGHT BACK WHERE WE ARE NOW? WILL THE BOUNDARY LIFT
BACK NORTH AND PUT US IN A MORE WARM SECTOR-LIKE AIR MASS? YOU CAN
FIND A FEW ENSEMBLE MEMBERS THAT SUPPORT EACH OF THESE SCENARIOS,
AND PROBABLY OTHERS AS WELL. SO AT THIS POINT, CONFIDENCE IS VERY
LOW FOR THE FORECAST PAST THURSDAY.
AVIATION /06Z MONDAY THROUGH FRIDAY/
AT KCLT AND ELSEWHERE: SHOWERS AND THUNDERSTORMS HAVE FINALLY BEGUN
TO TAPER OFF FOR THE NIGHT, WITH DECENT COVERAGE STILL NORTH OF CLT
AND ACROSS THE I-40 CORRIDOR, BUT A TRANSITION TO PATCHY DRIZZLE
EVERYWHERE ELSE. COVERAGE OVER THOSE PORTIONS OF THE TERMINAL
FORECAST AREA WHERE SHOWERS ARE STILL OCCURING SHOULD DIMINISH
OVER THE NEXT HOUR OR TWO, GIVING WAY TO ANOTHER MURKY NIGHT.
BOTH VISIBILITY AND CEILINGS HAVE BEEN HIGHLY VARIABLE TONIGHT,
WITH SOME SITES TOGGLING FROM LIFR TO VFR AND BACK AGAIN MULTIPLE
TIMES PER HOUR. HAVE GENERALLY GONE PESSIMISTIC IN THE 06Z
TAFS, WHICH CONTINUE TO FEATURE IFR TO LIFR RESTRICTIONS, MOSTLY
CEILING-DRIVEN, AT ALL SIX TAF SITES. IMPROVEMENT TO MVFR, OR
BRIEFLY VFR, IS ADVERTISED ON MONDAY AFTERNOON, DURING WHICH TIME
COVERAGE OF SHOWERS WILL BE QUITE LOW. SCATTERED CONVECTION WILL
DEVELOP A LITTLE LATER THAN THE USUAL DIURNAL MAXIMUM, EXTENDING
FROM MID/LATE AFTERNOON INTO THE LATE EVENING. SOME DETERIORATION
IN CONDITIONS IS EXPECTED AGAIN ON MONDAY NIGHT, BUT NOT NEARLY
TO THE EXTENT WE'VE SEEN THE LAST SEVERAL NIGHTS...WITH MOST SITES
ONLY DROPPING TO MVFR OR IFR.
OUTLOOK: THE PATTERN WILL REMAIN UNSETTLED AND MURKY FOR THE
FORESEEABLE FUTURE, WITH AT LEAST SCATTERED DIURNAL CONVECTION,
POSSIBLY PERSISTING INTO THE OVERNIGHT HOURS, AND LOWERED VISIBILITY
AND CEILINGS FORECAST EACH NIGHT THROUGH AT LEAST THE END OF THE
WORK WEEK.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
MPR
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