546
FXUS62 KGSP 130009
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
809 PM EDT FRI JUN 12 2026
WHAT HAS CHANGED
UPDATED THE AVIATION DISCUSSION.
KEY MESSAGES
1. SHOWERS AND THUNDERSTORMS ARE FORECAST THROUGH THE WEEKEND,
MAINLY IN THE AFTERNOONS AND EVENINGS, WITH ISOLATED SEVERE STORMS
POSSIBLE. STORMS SATURDAY AND SUNDAY MAY POSE AN ADDITIONAL RISK
OF HEAVY RAINFALL.
2. HOT AND HUMID CONDITIONS CONTINUE THROUGH THE WEEKEND, FOLLOWED
BY DRIER AND SLIGHTLY BELOW-NORMAL TEMPERATURES MONDAY AND EARLY
NEXT WEEK.
DISCUSSION
KEY MESSAGE 1: SHOWERS AND THUNDERSTORMS ARE FORECAST THROUGH THE
WEEKEND, MAINLY IN THE AFTERNOONS AND EVENINGS, WITH ISOLATED
SEVERE STORMS POSSIBLE. STORMS SATURDAY AND SUNDAY MAY POSE AN
ADDITIONAL RISK OF HEAVY RAINFALL.
A NARROW UPPER RIDGE EXTENDS UP THE EASTERN SEABOARD AS OF MIDDAY
FRIDAY. AN UPPER LOW SOUTH OF HUDSON BAY WILL ADVANCE SLOWLY
EASTWARD THROUGH THE WEEKEND; SHORTWAVES ROTATING THROUGH THE
SURROUNDING TROUGH ACROSS THE GREAT LAKES REGION WILL GRADUALLY
SUPPRESS THAT RIDGE AND PROMOTE GRADUAL HEIGHT FALLS THROUGH THE
REMAINDER OF THE WEEKEND AND INTO THE BEGINNING OF NEXT WEEK. A WEAK
COLD FRONT TRAILS THE FIRST OF THOSE SHORTWAVES, AND IS EXPECTED TO
CROSS THE SOUTHERN APPALACHIANS AND STALL ACROSS THE GSP CWA EARLY
SATURDAY MORNING. THAT FRONT SHOULD REACTIVATE LATER SATURDAY OR
SATURDAY NIGHT, IN ADVANCE OF A STRONGER SHORTWAVE AND COLD FRONT
MOVING THRU THE OHIO VALLEY SUNDAY.
AS OF MIDDAY FRIDAY A BOUNDARY, THE LEADING EDGE OF A REMNANT COLD
POOL FROM OVERNIGHT MCS, EXTENDS FROM NEAR KNOXVILLE TO HUNTSVILLE
AND ADVANCING SLOWLY EAST AND SOUTHEAST. 12Z CAMS DID NOT INITIALIZE
THIS WELL, BUT THERE APPEARS POTENTIAL FOR THE BOUNDARY TO INITIATE
STORMS AS IT CROSSES THE APPALACHIANS INTO OUR WESTERN CWA. LCLS
LOOK TO BE ON THE HIGH SIDE THIS AFTERNOON GIVEN THE NEAR-RECORD
TEMPERATURES, DESPITE THE MUGGY DEWPOINTS UNDER THE RIDGE WHICH
LIKELY WILL KEEP THE ACTIVITY SOMEWHAT ISOLATED, EXCEPT PERHAPS
ALONG THE COLD POOL BOUNDARY. 2000-2500 J/KG SBCAPE APPEARS A SAFE
BET AND SFC-6KM SHEAR WILL BE NO MORE THAN 20 KT, SO PULSE MODE
WOULD BE FAVORED. SFC-MIDLEVEL DELTA-THETA-E IS 30-35 K ON THE NAM
DUE TO THE PROFILES BEING DRY ALOFT, WHICH IS HIGHER THAN WE SEE
ON MOST DAYS THIS TIME OF YEAR; THAT PROBABLY WEIGHED INTO SPC'S
DECISION TO INCLUDE MOST OF OUR CWA IN A RISK AREA ON THE DAY 1
OUTLOOK FOR STORMS TO PRODUCE DAMAGING MICROBURSTS. THE SPARSE
CAM RESPONSE COULD BE AN INDICATOR THAT THE DRY AIR IS TOO MUCH
OF A LIMITING FACTOR FOR DEEP CONVECTION WITHOUT STRONG FORCING,
BUT AS NOTED ABOVE, POOR PERFORMANCE OF CAMS WITH THIS MORNING'S
UPSTREAM CONVECTION AND ON RECENT AFTERNOONS LEADS US TO PLACE LESS
WEIGHT TO THEIR DEPICTIONS THAN ON A TYPICAL AFTERNOON. ASSUMING THE
COLD POOL MIXES OUT WITH TIME, THERE REMAINS THE POTENTIAL FOR THE
SHORTWAVE ITSELF TO INITIATE STORMS THIS EVENING WITH LCLS LOWERING
AND POTENTIAL FOR OUTFLOW BOUNDARIES TO FOCUS NEW DEVELOPMENT.
MOISTURE POOLING NEAR THE STALLED FRONT SATURDAY COULD HAVE
THE EFFECT OF ENHANCING DEVELOPMENT NEAR THE BOUNDARY BUT
REDUCING DELTA-THETA-E AND DCAPE, WITH SEVERE POTENTIAL LOWER AS
A RESULT. HOWEVER THAT COULD LEAD THE HEAVY RAIN THREAT TO TICK
UPWARD A BIT, DUE TO THE EXTRA MOISTURE AND DUE TO STEERING FLOW
BEING SLIGHTLY WEAKER AND ALSO PARALLEL TO THE FRONT. THE HRRR
TRENDS MORE ACTIVE DIURNALLY ON SATURDAY, THOUGH THE OTHER CAMS
DEPICT EVEN LESS COVERAGE; CONFIDENCE REMAINS LOW AS DO POPS,
REMAINING NO BETTER THAN ~30%. SOME MODELS DEPICT NONDIURNAL
CONVECTIVE COVERAGE SATURDAY NIGHT AS THE FRONT REACTIVATES. SUNDAY,
PWATS AND 0-6KM SHEAR INCREASE WITH TROUGH DEVELOPING AHEAD OF THE
OH VALLEY FRONT AND SHORTWAVE. CONVERGENCE WITHIN THE TROUGH IS
EXPECTED TO PRODUCE BETTER CONVECTIVE COVERAGE THAN THE PREVIOUS
TWO DAYS, WITH BOTH HEAVY/EXCESSIVE RAIN AND CLUSTERS OF STORMS
POSING A DAMAGING WIND/HAIL THREAT APPEARING POSSIBLE.
THE COLD FRONT SHOULD SETTLE SOUTHWARD ACROSS THE CWA MONDAY, THOUGH
PWATS REMAIN AT OR ABOVE CLIMO IN THE SOUTHEAST HALF OF THE AREA
THROUGH EARLY TUESDAY PER LREF, THE EURO AND CANADIAN ENSEMBLES
CONTINUING TO BE QUICKER TO DRY US OUT THAN THE GEFS. 20-50% POPS
LINGER THROUGH EARLY TUESDAY BEFORE DECREASING THAT AFTERNOON
INTO WEDNESDAY. CHANCES INCREASE AGAIN IN ADVANCE OF THE NEXT
FRONT THURSDAY.
KEY MESSAGE 2: HOT AND HUMID CONDITIONS CONTINUE THROUGH THE WEEKEND,
FOLLOWED BY DRIER AND SLIGHTLY BELOW-NORMAL TEMPERATURES MONDAY
AND EARLY NEXT WEEK.
THOUGH THE UPPER RIDGE WILL SLOWLY BE SUPPRESSED THROUGH THE
WEEKEND, NO SIGNIFICANT AIRMASS CHANGE IS EXPECTED THROUGH
SUNDAY. TEMPS WILL TOP OUT IN THE LOWER TO MID 90S THIS (FRIDAY)
AFTERNOON EAST OF THE MOUNTAINS THOUGH IT LOOKS QUESTIONABLE WHETHER
RECORDS WILL BE REACHED. SOUPY DEWPOINTS IN THE UPPER 60S TO LOWER
70S WILL MAKE FOR VERY HIGH HEAT INDICES. A HEAT ADVISORY REMAINS
IN EFFECT FOR MECKLENBURG-UNION-CABARRUS COUNTIES IN NC WHERE HEAT
INDICES AT CALIBRATED STATIONS ARE EXPECTED TO PUSH PAST 105. THE
WEAK FRONT REACHING THE AREA TONIGHT SHOULD BRING SLIGHTLY LOWER
DEWPOINTS TO THE NORTHERN ZONES SATURDAY, AND TEMPERATURES BACK OFF
JUST ENOUGH ACROSS THE AREA TO PRECLUDE ANY HEAT HEADLINES AT THIS
TIME. DEWPOINTS AND TEMPERATURES MAY CREEP UPWARD AGAIN SUNDAY BUT
CONFIDENCE IS LOW OWING TO THE POSITION OF THE FRONT AND ALSO THE
POTENTIAL FOR CONVECTIVE OUTFLOWS TO KEEP TEMPS IN CHECK THAT DAY.
A MORE ROBUST COLD FRONT ARRIVING BY EARLY MONDAY IS LIKELY TO
INDUCE A MORE SUBSTANTIAL DROP IN DEWPOINTS OVER MUCH OF THE
AREA MONDAY AFTERNOON, AND ALSO BRING TEMPS BACK TO AROUND IF NOT
BELOW NORMAL MONDAY. THAT AIRMASS SHOULD STICK AROUND FOR TUESDAY,
MODIFYING SLIGHTLY WEDNESDAY AND FURTHER ON THURSDAY AS SW FLOW
REDEVELOPS AHEAD OF THE NEXT SYSTEM.
AVIATION /00Z SATURDAY THROUGH WEDNESDAY/
AT KCLT AND ELSEWHERE: ISOLATED SHOWERS AND TSRA SHOULD BE TRENDING
DOWNWARD THROUGH MIDNIGHT, WITH CONFIDENCE ONLY FOR VCSH AT THIS
TIME. KAVL COULD SEE A BRIEF PERIOD OF MVFR VSBY BEFORE SUNRISE FROM
BR. THIS IS MAINLY DUE TO RAIN DURING THE DAY. WINDS BECOME MORE
N/NW OVERNIGHT AND VERY LIGHT, WITH PERIOD OF CALM POSSIBLE. WINDS
TOGGLE SW BY SATURDAY AFTERNOON. LOWER CHANCES FOR ANY SHRA OR TSRA
OUTSIDE THE MOUNTAINS, BUT KEEP A PROB30 AT KAVL DURING THE
AFTERNOON. SKIES REMAIN VFR AND SCT THROUGH THE ENTIRE TAF PERIOD.
OUTLOOK: DIURNAL CONVECTION AND ASSOCIATED RESTRICTIONS ARE EXPECTED
INTO EARLY NEXT WEEK. VALLEY FOG AND LOW STRATUS IS POSSIBLE EACH
MORNING, PRIMARILY IN THE MOUNTAIN VALLEYS.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
CP/JCW
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