376
FXUS62 KGSP 010008
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
808 PM EDT TUE JUN 30 2026
WHAT HAS CHANGED
UPDATED THE AVIATION DISCUSSION FOR THE 00Z TAFS.
KEY MESSAGES
1. HEAT RISK WILL STEADILY INCREASE THROUGH THE WEEK, WITH HEAT
INDICES LIKELY EXCEEDING 100 DEGREES ACROSS MUCH OF THE PIEDMONT
AND FOOTHILLS, ESPECIALLY BY MID TO LATE WEEK. DAILY THUNDERSTORMS
WILL ALSO BE POSSIBLE ACROSS THE MOUNTAINS.
2. THE HEAT THREAT BEGINS TO WANE LATE WEEKEND AND INTO EARLY
NEXT WEEK WITH A RETURN TO A MORE TRADITIONAL MID SUMMER PATTERN
FEATURING SEASONABLE TEMPERATURES AND DAILY STORM CHANCES.
DISCUSSION
KEY MESSAGE 1: HEAT RISK WILL STEADILY INCREASE THROUGH THE WEEK,
WITH HEAT INDICES LIKELY EXCEEDING 100 DEGREES ACROSS MUCH OF
THE PIEDMONT AND FOOTHILLS, ESPECIALLY BY MID TO LATE WEEK. DAILY
THUNDERSTORMS WILL ALSO BE POSSIBLE ACROSS THE MOUNTAINS.
THE SYNOPTIC PATTERN STARTS OFF RATHER AMPLIFIED TODAY WITH A DEEP
TROUGH DIGGING THROUGH THE GREAT BASIN WHILE AN ANOMALOUS UPPER
RIDGE CONTINUES TO BUILD OVER THE TENNESSEE VALLEY. WITH TIME, THE
UPPER RIDGE WILL MIGRATE INTO THE SOUTHERN APPALACHIANS BY LATE WEEK
THROUGH THE 4TH OF JULY HOLIDAY WEEKEND BRINGING A ROUND OF HOT
TEMPERATURES TO THE AREA. 500MB HEIGHTS AND 850MB TEMPERATURES WILL
BOTH BE IN THE 99TH PERCENTILE FOR EARLY JULY, WHICH WILL SUPPORT
HOT AFTERNOON HIGH TEMPERATURES IN THE UPPER 90S TO LOW 100S. EVEN
MOUNTAIN VALLEYS WILL BE WARM WITH HIGHS IN THE LOW TO MID 90S.
WHILE TEMPERATURES WILL DEFINITELY BE HOT, THE MAIN UNCERTAINTY IS
WHETHER WE WILL REACH HEAT ADVISORY CRITERIA WITH HEAT INDICES OF
105 DEGREES OR GREATER. FORECAST SOUNDINGS CONTINUE TO DEPICT A
DEEPLY MIXED BOUNDARY LAYER EXTENDING TO NEARLY 700MB. THIS DEEP
MIXING WILL SUPPORT AGGRESSIVE MIXING OUT OF DEWPOINTS WITH SURFACE
DEWPOINTS POTENTIALLY FALLING AS LOW AS THE UPPER 50S TO LOW 60S.
THE LACK OF A MORE HUMID AIRMASS WILL GENERALLY PRECLUDE HEAT INDEX
VALUES REACHING ADVISORY CRITERIA. THAT BEING SAID, PRECAUTIONS WILL
STILL NEED TO BE TAKEN AS AIR TEMPERATURES IN THE LOW 100S WILL
STILL POSE A RISK OF HEAT RELATED ILLNESS.
ADDITIONALLY, DIURNALLY DRIVEN THUNDERSTORMS WILL BE POSSIBLE ACROSS
THE MOUNTAINS EACH AFTERNOON WHERE TERRAIN EFFECTS WILL BE
SUFFICIENT TO OVERCOME AN OTHERWISE UNFAVORABLE ENVIRONMENT FOR
CONVECTIVE INITIATION. WHAT STORMS DO DEVELOP WILL HAVE THE
POTENTIAL TO BECOME STRONG TO SEVERE OWING TO MODERATE TO HIGH
INSTABILITY, STEEP LAPSE RATES, AND MODEST DCAPE. THE MAIN THREAT
WOULD BE FOR LOCALLY DAMAGING WINDS AND SMALL HAIL.
KEY MESSAGE 2: THE HEAT THREAT BEGINS TO WANE LATE WEEKEND AND INTO
EARLY NEXT WEEK WITH A RETURN TO A MORE TRADITIONAL MID SUMMER
PATTERN FEATURING SEASONABLE TEMPERATURES AND DAILY STORM CHANCES.
BY SUNDAY, THE UPPER RIDGE ASSOCIATED WITH THE HOLIDAY HEAT WAVE
WILL HAVE WEAKENED AND WILL BE SHIFTING OFF THE ATLANTIC COAST AS
WEAK NORTHERN STREAM FLOW DIPS FARTHER SOUTH INTO THE OHIO VALLEY.
AS SUCH, AFTERNOON HIGH TEMPERATURES WILL RETURN TO THE LOW TO MID
90S AND MORE IN LINE WITH SEASONAL AVERAGES FOR EARLY JULY. THIS
SHOULD ALSO KEEP HEAT INDICES IN CHECK. IN ADDITION, THE RETURN OF
ACTIVE NORTHWEST FLOW AND MOISTURE RETURN FROM THE GULF/ATLANTIC
WILL SUPPORT AT LEAST SCATTERED TO NUMEROUS AFTERNOON SHOWERS AND
STORMS EACH DAY. THIS WILL LIKELY BE FURTHER AMPLIFIED BY SEVERAL
PASSING WEAK SHORTWAVE TROUGHS. AS WITH ANY SUMMER STORMS, AT LEAST
SEVERAL MAY BECOME STRONG TO SEVERE WITH LOCALLY DAMAGING WINDS AND
SMALL HAIL.
AVIATION /00Z WEDNESDAY THROUGH SUNDAY/
AT KCLT AND ELSEWHERE: EXPECT VFR CONDITIONS TO PREVAIL AT MOST
TERMINALS THRU THE 00Z TAF PERIOD. THE MAIN EXCEPTION WILL BE
KAVL, WHERE THERE IS CURRENTLY A ROBUST THUNDERSTORM JUST NW OF
THE TERMINAL. AS SUCH, I HAVE PREVAILING TSRA WITH 3SM VISBY AND
A TEMPO FOR VRB10G30KT FOR THE FIRST HOUR OF THE TAF. AFTER THIS
CONVECTION SETTLES DOWN, THEY HAVE A GOOD CHANCE OF SEEING ANOTHER
ROUND OF FOG/LOW STRATUS OVERNIGHT AND INTO THE MORNING. THUS, I
HAVE IFR RESTRICTIONS BEGINNING AROUND 08Z, WITH A TEMPO FOR LIFR
FROM 09 TO 13Z. ANY LINGERING RESTRICTIONS SHOULD BURN OFF BY 13Z
OR SO. ANOTHER ROUND OF SCT CONVECTION IS EXPECTED OVER THE NC MTNS
TOMORROW AFTN/EVENING, SO KAVL HAS A PROB30 FOR TSRA FOR TOMORROW
AFTN/EVENING. CONVECTIVE CHANCES APPEAR TOO LOW TO MENTION AT THE
OTHER TAF SITES. WINDS WILL GENERALLY BE LIGHT AND VARIABLE TO CALM
THROUGH THE MORNING. THEY WILL GENERALLY FAVOR A SELY DIRECTION
TOMORROW AFTN/EVENING WITH SPEEDS AROUND 5 KTS.
OUTLOOK: DIURNAL SHOWERS AND THUNDERSTORMS ARE EXPECTED MAINLY
ACROSS THE MTNS THROUGH THE WORKWEEK. MOUNTAIN VALLEY FOG/LOW
STRATUS WILL BE POSSIBLE EACH MORNING.
CLIMATE
RECORDS FOR 07-02
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAVL 93 1970 65 1943 70 2018 44 1988
1954
1931
KCLT 101 1931 64 1943 76 1991 56 2008
1970
1931
KGSP 101 1954 66 1943 77 1931 53 1899
RECORDS FOR 07-03
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAVL 93 1970 65 1988 70 2018 50 2008
1897 1931 1937
1932
KCLT 99 1931 70 1988 76 1925 56 2010
KGSP 99 2016 70 1988 77 1925 56 1984
1970
1953
RECORDS FOR 07-04
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAVL 97 1948 68 1976 70 2016 51 1986
KCLT 99 1993 70 1968 76 1993 55 1933
1955
KGSP 100 1993 70 1988 75 2018 58 2021
1996
1933
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
JPT/TW
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