613
FXUS62 KGSP 172347
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
747 PM EDT WED JUN 17 2026
WHAT HAS CHANGED
THE AVIATION FORECAST WAS UPDATED TO REFLECT THE RECENT 00Z TAF
ISSUANCE.
KEY MESSAGES
1. FOLLOWING ONE MORE DRY DAY WEDNESDAY, RAIN CHANCES INCREASE
FOR THURSDAY AND THURSDAY NIGHT AS REMNANTS OF TROPICAL STORM
ARTHUR CROSS THE AREA. WIDESPREAD RAINFALL AND EMBEDDED THUNDER
ARE EXPECTED; INSTANCES OF LOCALLY HEAVY RAINFALL AND DAMAGING
WIND CANNOT BE RULED OUT. A COLD FRONT WILL BRING AN END TO THE
RAIN BY LATE FRIDAY.
2. DRIER CONDITIONS SETTLE IN OVER THE WEEKEND, BUT THE UNSETTLED
PATTERN CONTINUES INTO NEXT WEEK.
DISCUSSION
KEY MESSAGE 1: FOLLOWING ONE MORE DRY DAY WEDNESDAY, RAIN CHANCES
INCREASE FOR THURSDAY AND THURSDAY NIGHT AS REMNANTS OF TROPICAL
STORM ARTHUR CROSS THE AREA. WIDESPREAD RAINFALL AND EMBEDDED
THUNDER ARE EXPECTED; INSTANCES OF LOCALLY HEAVY RAINFALL AND
DAMAGING WIND CANNOT BE RULED OUT. A COLD FRONT WILL BRING AN
END TO THE RAIN BY LATE FRIDAY.
ALL QUIET ACROSS THE REGION THIS EVENING AS WEAK QUASI-ZONAL FLOW
ALOFT CONTINUES, AND A NOSE OF HIGH PRESSURE ACROSS THE AREA
GENERALLY KEEPS THE ATMOSPHERE SUPPRESSED. THOUGH OBSERVED PROFILES
DO NOT EXHIBIT A TRUE INVERSION, LAPSE RATES ARE PALTRY, AND SANS
ANY GOOD UPPER FORCING, MOSTLY CLEAR CONDITIONS WILL PERSIST THROUGH
THE OVERNIGHT INTO EARLY THURSDAY.
THE BIGGER STORY REMAINS THE INFLUENCE OF TROPICAL STORM ARTHUR ON
OUR FORECAST THE NEXT TWO DAYS. WATER VAPOR IMAGERY PLACES ARTHUR
OFF THE COAST OF SOUTHERN TEXAS, AND MOVING SLOWLY NORTHEASTWARD.
OVER THE NEXT 24 HOURS, OPERATIONAL GUIDANCE IS IN GOOD AGREEMENT
THAT IT'LL LIFT ACROSS THE DEEP SOUTH, ARRIVING IN THE WESTERN
CAROLINAS BY LATE THURSDAY. ON ITS LEADING EDGE, MOST GUIDANCE
STILL DEPICTS A STRONG 35-45KT LLJ ON THE 850MB CHARTS...RESULTING
IN WINDY CONDITIONS ACROSS MOST OF THE AREA FOR MUCH OF THURSDAY.
THE PROBABILITY OF REACHING TRUE WIND ADVISORY CRITERIA REMAINS
LOW, BUT FORECAST GUSTS OF 30KTS OR SO ARE STILL VERY UNUSUAL FOR
MID JUNE.
BY 00Z FRIDAY, ENSEMBLE CONSENSUS PLACES ARTHUR'S REMNANTS EITHER
OVER THE GSP CWA OR JUST TO ITS WEST. WHILE PRIOR FORECASTS
SUGGESTED POSSIBLE INTERACTION BETWEEN ARTHUR AND AN APPROACH
SHORTWAVE TROUGH DIPPING OUT OF THE MIDWEST, GUIDANCE INCREASINGLY
SUGGESTS THE MORE POTENT INTERACTION WILL BE BETWEEN ARTHUR AND
A REMNANT FRONTAL BOUNDARY LOCATED TO OUR SOUTH. MOST OF THE
AVAILABLE HI-RES MODELS DEPICT A DECAYING MCS TRACKING ACROSS
CENTRAL GEORGIA ON THURSDAY AFTERNOON, ARRIVING IN THE SOUTHERN
REACHES OF THE UPSTATE THAT EVENING...AND PROVIDING THE FIRST
IMPETUS FOR SEVERE WEATHER. WHATEVER CONVECTION MAKES A RUN AT THE
AREA WILL INDEED FIND ITSELF IN A FAIRLY LIMITED
ENVIRONMENT...FEATURING MODEST DEEP-LAYER SHEAR AND VERY LIMITED LOW-
LEVEL SHEAR. THIS WOULD PRIMARILY MANIFEST AS AN ISOLATED DAMAGING
WIND THREAT. THE EXCEPTION COULD BE IN THE IMMEDIATE VICINITY THE
FRONTAL BOUNDARY, WHERE LOW-LEVEL SHEAR PROFILES MAY BE AMPLIFIED
AND, COMBINED WITH THE FOCUSING EFFECT OF THE BOUNDARY, CONTRIBUTE
TO A SOMEWHAT HIGHER SEVERE WEATHER THREAT.
HOWEVER, ENSEMBLES BROADLY INDICATE THE FRONT WILL REMAIN TO OUR
SOUTH THROUGH THE DURATION OF THE EVENT...SO THIS SHOULD HAVE
LIMITED EFFECT ON US IN THE UPSTATE AND PIEDMONT
OTHERWISE, EXPECT WIDESPREAD RAINFALL AS THE WAVE PASSES OVERHEAD.
IT REMAINS A LITTLE UNCLEAR WHERE THE GREATEST RAINFALL TOTALS WILL
BE FOCUSED. SEVERAL OPERATIONAL MEMBERS DEPICT THE FORMATION OF A
COMPACT MESOLOW OVER THE UPSTATE, PERHAPS IN ASSOCIATION WITH THE
DECAYING MCS REFERENCED EARLIER. OPERATIONAL GUIDANCE GENERALLY
AGREES ON A CORRIDOR OF 2-3.5" OF RAINFALL DROPPING SOMEWHERE
SOUTH OF I-85...BUT CONTINUES TO DISAGREE ON ITS PLACEMENT.
GIVEN THE INCREASED LIKELIHOOD FOR ARTHUR TO INTERACT WITH THE
PRE-EXISTING FRONTAL BOUNDARY, AND NOT THE UPSTREAM SHORTWAVE,
IT LOOKS MORE LIKELY THAT THE HEAVIEST RAINFALL WON'T OCCUR OVER
THE NC MOUNTAINS, BUT RATHER SOMEWHERE IN THE UPSTATE. A NUMBER OF
MODEL SOURCES EVEN BRING THE AXIS OF HEAVIEST QPF SOUTH OF THE CWA
ENTIRELY. CONFIDENCE IN THE BIGGER PICTURE (THAT THERE WILL BE AN
AXIS OF HEAVIER RAIN SOMEWHERE IN SC) IS IMPROVING, BUT CONFIDENCE
ON THE DETAILS (EXACTLY WHERE THAT AXIS WILL SET UP) REMAINS LOW.
BY MID-DAY FRIDAY, WHAT REMAINS OF ARTHUR'S MID-LEVEL TROUGH WILL
PIVOT TO OUR EAST. THE APPROACHING SHORTWAVE WILL FINALLY PUSH A
REINFORCING COLD FRONT INTO THE AREA BY EARLY AFTERNOON FRIDAY, AND
GUIDANCE IS IN DECENT AGREEMENT THAT INCREASINGLY DRY CONDITIONS
WILL PERSIST THE REST OF THE DAY AS WEAK CAA AND DRY ADVECTION
SET IN.
KEY MESSAGE 2: DRIER CONDITIONS SETTLE IN OVER THE WEEKEND, BUT THE
UNSETTLED PATTERN CONTINUES INTO NEXT WEEK.
HIGH PRESSURE WILL SETTLE INTO THE AREA ON SATURDAY, BRINGING AN END
TO RAIN CHANCES AND USHERING IN A PERIOD OF QUIETER WEATHER THAT
SHOULD PERSIST THROUGH SUNDAY. TEMPERATURES WILL BE NEAR-NORMAL
THROUGH THE WEEKEND...MEANING HIGHS IN THE UPPER 80S TO LOWER 90S
IN MOST LOCATIONS. NO CONVECTION IS FORECAST.
BY SUNDAY NIGHT...WITH THE REMNANT FRONT AND ASSOCIATED BAROCLINIC
ZONE STILL TO OUR SOUTH...WE'LL COME UNDER THE INFLUENCE OF ANOTHER
UPPER DISTURBANCE, A TROUGH TRACKING OUT OF THE CENTRAL CONUS.
IT'S UNCLEAR EXACTLY WHEN THE BEST FORCING WILL INTERSECT THE
BAROCLINIC ZONE AT THE SURFACE. FURTHER, AS PER SOME LREF MEMBERS
THIS TROUGH COULD WIND UP BEING JUST THE FIRST IN A SERIES OF
WAVES ROTATING AROUND BROADER TROUGHING OVER NEW ENGLAND AND
EASTERN CANADA. THUS, EXPECT MOST OF NEXT WEEK TO BE ACTIVE,
IF PERHAPS MORE LIKELY TO JUST BE DIURNAL SUMMERTIME CONVECTION
THAN ANY MORE ORGANIZED SEVERE OR HEAVY RAIN THREAT.
AVIATION /00Z THURSDAY THROUGH MONDAY/
AT KCLT AND ELSEWHERE: VFR CONDITIONS AND SW WINDS AROUND 10 KTS
ARE EXPECTED THROUGH THE EVENING ACROSS THE TERMINAL FORECAST
AREA. WINDS ARE FORECAST TO INCREASE A BIT AND POSSIBLY BECOME
GUSTY LATE TONIGHT AT THE UPSTATE SC TERMINALS. A BRIEF PERIOD OF
LOW CLOUD DEVELOPMENT IS AGAIN EXPECTED FROM THE PRE-DAWN HOURS
UNTIL SHORTLY AFTER SUNRISE, MAINLY ACROSS THE SOUTHERN HALF OF
THE AREA. MVFR CIGS ARE FORECAST AT ALL SITES EXCEPT KAVL AND KHKY
AT SOME POINT DURING THAT TIME FRAME. IFR IS POSSIBLE, ALTHOUGH
IT DOESN'T APPEAR LIKELY AT THIS TIME, BUT FEW/SCT LAYERS IN THE
007-009 RANGE ARE PRUDENT IN ORDER TO ADDRESS THAT POTENTIAL.
SW WINDS BECOME GUSTY AT ALL SITES BY LATE THU MORNING, WITH GUSTS
TO AROUND 25 KTS EXPECTED AT MOST SITES DURING THE AFTERNOON. MORE
UNSTABLE CONDITIONS ARE EXPECTED TO RESULT IN DIURNAL CONVECTIVE
DEVELOPMENT THU AFTERNOON AND EVENING, WITH PROB30S FOR TSRA
WARRANTED AT ALL SITES BETWEEN 18-24Z.
OUTLOOK: A BRIEF LULL IN CONVECTION IS EXPECTED DURING THE LATE
EVENING AND EARLY PART OF THE OVERNIGHT THU NIGHT. ADDITIONAL
CONVECTION IS EXPECTED LATE THU NIGHT INTO EARLY FRI,
AS THE REMNANTS OF TROPICAL STORM ARTHUR PASS CLOSE TO THE
AREA. DRY/CONVECTIVELY INACTIVE WEATHER WILL RETURN BY FRI NIGHT
AND CONTINUE THROUGH AT LEAST SAT NIGHT. DIURNAL CONVECTION IS
EXPECTED TO RETURN EARLY NEXT WEEK.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
JDL/MPR
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