648
FXUS62 KGSP 171053
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
653 AM EDT WED JUN 17 2026
WHAT HAS CHANGED
CONFIDENCE IS INCREASING THAT AXIS OF HEAVIEST RAINFALL HAS SHIFTED
OUT OF THE NC MOUNTAINS AND INTO THE SC UPSTATE AND NE GA.
CONFIDENCE REMAINS LOW ON RAINFALL AMOUNTS AND ALSO ON ANY SEVERE
WEATHER THREAT THURSDAY INTO THURSDAY NIGHT.
THE AVIATION DISCUSSION WAS UPDATED FOR THE 12Z TAF ISSUANCE.
KEY MESSAGES
1. RAIN CHANCES INCREASE AGAIN THURSDAY INTO FRIDAY AS THE REMNANTS
OF A TROPICAL LOW APPROACHES THE AREA FROM THE GULF. LOCALLY HEAVY
RAINFALL AND DAMAGING WINDS CANNOT BE RULED OUT. DRIER CONDITIONS
RETURN OVER THE WEEKEND BEHIND A COLD FRONT.
DISCUSSION
KEY MESSAGE 1: RAIN CHANCES INCREASE AGAIN THURSDAY INTO FRIDAY AS
THE REMNANTS OF A TROPICAL LOW APPROACHES THE AREA FROM THE GULF.
LOCALLY HEAVY RAINFALL AND DAMAGING WINDS CANNOT BE RULED OUT.
DRIER CONDITIONS RETURN OVER THE WEEKEND BEHIND A COLD FRONT.
UPPER SHORTWAVE TROUGH IS CURRENTLY CROSSING THE CENTRAL AND
SOUTHERN APPALACHIANS AND WILL EXIT TO THE EAST BY DAYBREAK. FLOW
WILL VEER TO W/NWLY IN ITS WAKE THIS MORNING, HELPING CLEAR OUT
THE CLOUDS AND KEEP DRY CONDITIONS ACROSS THE CWFA TODAY. TEMPS
WILL REBOUND UNDER MOSTLY SUNNY SKIES, BUT HUMIDITY WILL STAY IN
CHECK, AS AIR REMAINS RELATIVELY DRY.
A VIGOROUS SHORTWAVE WILL DIVE INTO THE GREAT LAKES AND HELP
DEEPEN A BROAD 500 MB LONGWAVE TROUGH AXIS ACROSS THE MS VALLEY
REGION. WHILE THE BULK OF THE ENERGY WILL STAY WELL TO OUR NORTH,
THERE WILL BE ENOUGH HEIGHT FALLS FOR THE TROUGH TO PICK UP A
TROPICAL DISTURBANCE OUT OF THE NW GULF AND START STEERING IT
EAST ACROSS THE GULF STATES. SOUTHWESTERLY 850 MB FLOW INCREASES
AHEAD OF THE DEEPENING TROUGH AND TROPICAL WAVE, MAKING FOR AN
UNUSUALLY WINDY DAY FOR MID-JUNE ACROSS THE REGION. WIND GUSTS OF
25-35 MPH LOOK LIKELY THURSDAY AFTN. THE LATEST GLOBAL MODELS ARE
IN BETTER AGREEMENT ON TIMING THE LOW THRU GA AND THE CAROLINAS
THURSDAY EVENING THRU FRIDAY AFTN. HOWEVER, THEY STILL DISAGREE
ON HOW FAR NORTH IT WILL TRACK. THE GFS CONTINUES TO BE WEAKER AND
FURTHER SOUTH, WHILE THE ECMWF IS STILL ON THE STRONGER SIDE AND A
LITTLE NORTH. THE CANADIAN IS CLOSE TO THE ECMWF WITH A STRONGER
MESO-LOW AND SHOWS AN AXIS OF HEAVY RAIN ROUGHLY ALONG THE I-85
CORRIDOR, AS IT TRACK BY THURSDAY NIGHT. THE GFS AND ECMWF HAS
A SIMILAR QPF SWATH, BUT A LITTLE SOUTH. THE LATEST NBM QPF HAS
TRENDED A LITTLE SOUTH WITH AXIS OF HEAVIEST RAINFALL, SHOWING 1-2"
OF QPF ACROSS THE SOUTHERN UPSTATE AND THE GA PIEDMONT.
AS FOR SEVERE WEATHER THREAT: ENERGY FROM THESE TWO SYSTEMS
SHOULD SUPPORT CONVECTION ALONG/AHEAD OF THE TROPICAL REMNANTS,
AS LEADING EDGE ENVIRONMENT SHOULD BECOME FAIRLY UNSTABLE. SHEAR
PROFILES ARE STILL RATHER MARGINAL FOR ORGANIZED CONVECTION, AS
FORECAST SOUNDINGS SHOW STRONG LOW-LEVEL FLOW WITH WEAK MID-LEVEL
FLOW, WHICH MAY RESULT IN CONVECTION STRUGGLING TO BALANCE ALONG
OUTFLOWS. THE 00Z CAMS SHOW AN MCV SIGNATURE ON THE SIMULATED
REFLECTIVITY, BUT STRONGEST CONVECTION REMAINING LARGELY SOUTH OF
THE CWFA. IN ANY CASE, DAMAGING WIND GUSTS LOOKS TO BE THE MAIN
THREAT. A COLD FRONT WILL PUSH IN FROM THE NW LATE THURSDAY NIGHT
THRU FRIDAY MORNING. THE LATEST GUIDANCE SUGGESTS THE FRONT MAY
BE ABOUT TO EXIT THE CWFA TO THE SOUTHEAST BY PEAK HEATING. BUT
THE SE EDGE OF THE AREA MAY SEE SOME REDEVELOPMENT OF CONVECTION
FRIDAY AFTN. THE NEW DAY 3 CONVECTIVE OUTLOOK HAS A MARGINAL RISK
TO OUR SOUTH. TEMPS WILL BE AT OR SLIGHTLY ABOVE NORMAL THURSDAY,
AND NEAR TO SLIGHTLY BELOW NORMAL FRIDAY.
THE WEEKEND LOOKS LARGELY DRY WITH NEAR NORMAL TEMPS UNDER A
QUASI-ZONAL FLOW AND WEAK SFC HIGH CROSSING THE MID-ATLANTIC. COULD
SEE AT LEAST SCATTERED DIURNAL CONVECTION ACROSS THE MOUNTAINS
SUNDAY, AS MOISTURE INCREASES AHEAD OF THE NEXT FRONT. THAT FRONT
COULD BRING MORE WIDESPREAD SHOWERS AND STORMS MONDAY. TEMPS WILL
BE NEAR NORMAL THRU THE WEEKEND AND EARLY NEXT WEEK.
AVIATION /12Z WEDNESDAY THROUGH SUNDAY/
AT KCLT AND ELSEWHERE: LIFR TO IFR STRATUS HAS REALLY EXPANDED
ACROSS PORTIONS OF THE UPSTATE, SOUTHERN NC PIEDMONT AND THE
MOUNTAIN VALLEYS. THE CLOUDS SHOULD DISSIPATE WITHIN AN HOUR OR SO
AFTER 12Z. WILL CONTINUE WITH TEMPOS FOR THE LOW CIGS THRU 13Z,
WHERE THE CLOUDS CAN BE SEEN ON SATELLITE IMAGERY. FROM THERE,
VFR CONDITIONS SHOULD PREVAIL THRU THIS EVENING. WINDS WILL PICK
UP OUT OF THE SW BY MIDDAY, WITH LOW-END GUSTS POSSIBLE ACROSS
THE UPSTATE AND KAVL LATE AFTN. SW WINDS WILL STAY UP TONIGHT,
AND SOME GUIDANCE GUIDANCE SUGGESTS GUSTINESS CONTINUES OR BEGINS
OVERNIGHT. LATEST GUIDANCE STILL NOT IN GREAT AGREEMENT ON MVFR
TO IFR STRATUS REDEVELOPING TONIGHT ACROSS NE GA AND INTO THE
UPSTATE. CONFIDENCE IS HIGHEST ON SOME MVFR CIGS AT KAND DEVELOPING
BETWEEN 06-12Z THURSDAY. ONCE AGAIN, KCLT WILL BE ON THE EDGE,
AND WILL HAVE JUST FEW015 LATE TONIGHT IN THE 12Z TAF.
OUTLOOK: MVFR TO IFR CIGS ARE EXPECTED TO SCATTER OUT AGAIN
THURSDAY MORNING. GUSTY SW WINDS EXPECTED ACROSS THE AREA THRU
THE DAY THURSDAY. MORE WIDESPREAD CONVECTION IS EXPECTED ACROSS
THE AREA THURSDAY AFTERNOON THROUGH FRIDAY. DRY WEATHER RETURNS
FOR THE WEEKEND.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
ARK
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