907
FXUS62 KGSP 092317
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
717 PM EDT THU JUL 9 2026
WHAT HAS CHANGED
SEVERE THUNDERSTORM CHANCES LOOK A LITTLE BETTER FRIDAY AFTERNOON AS
THE DAY 2 CONVECTIVE OUTLOOK SHOWS AN INCREASE TO MARGINAL RISK.
THE AVIATION DISCUSSION WAS UPDATED FOR THE 00Z TAFS.
KEY MESSAGES
1. CONTINUED HOT AND HUMID EAST OF THE MOUNTAINS INTO THE WEEKEND,
BUT NOT HOT ENOUGH TO REACH HEAT ADVISORY CRITERIA. IF YOU HAVE
OUTDOOR ACTIVITY PLANNED IN THE AFTERNOONS THROUGH SATURDAY,
MAKE SURE TO STAY HYDRATED AND TAKE FREQUENT BREAKS TO COOL OFF
AND AVOID HEAT-RELATED STRESS.
2. MAINLY DIURNAL SHOWERS AND THUNDERSTORMS WILL BE MOSTLY CONFINED
TO WESTERN NORTH CAROLINA AGAIN TODAY WITH AN ISOLATED SEVERE
STORM POSSIBLE. COVERAGE IMPROVES FOR FRIDAY AND THE WEEKEND,
WITH BETTER CHANCES FOR LOOSELY ORGANIZED SEVERE WEATHER. THE
RISK FOR FLASH FLOODING OVER THE MOUNTAINS WILL INCREASE INTO
THE EARLY PART OF NEXT WEEK.
DISCUSSION
KEY MESSAGE 1: CONTINUED HOT AND HUMID EAST OF THE MOUNTAINS INTO THE
WEEKEND, BUT NOT HOT ENOUGH TO REACH HEAT ADVISORY CRITERIA. IF YOU
HAVE OUTDOOR ACTIVITY PLANNED IN THE AFTERNOONS THROUGH SATURDAY,
MAKE SURE TO STAY HYDRATED AND TAKE FREQUENT BREAKS TO COOL OFF
AND AVOID HEAT-RELATED STRESS.
ALTHOUGH THE BERMUDA HIGH CONTINUES TO WEAKEN AND BE SHUNTED
OFF TO THE SOUTH FOR THE NEXT FEW DAYS, WE RETAIN THE TYPICAL
SUMMERTIME HEAT AND HUMIDITY EVEN IN THE FACE OF INCREASING STORM
CHANCES. BEGINNING TONIGHT, THE WESTERN CAROLINAS ARE MORE UNDER
THE INFLUENCE OF A BROAD AND BAGGY MID/UPPER TROF THAT WILL HAVE
SEVERAL WEAK SHORT WAVES RIPPLING THROUGH IT. THE EXPECTATION
IS THAT STORMS WILL BE SCATTERED ENOUGH THROUGH THE EARLY PART
OF THE AFTERNOON FRIDAY AND SATURDAY TO ALLOW SIGNIFICANT WARMUP
WITH TEMPS CLIMBING ABOUT FIVE DEGREES ABOVE NORMAL. THIS COULD
EASILY NOT WORK OUT DEPENDING ON UPSTREAM CONVECTION AND REMNANT
CLOUDINESS...MORE ON THAT BELOW. THE COMBO OF FORECAST HIGH TEMPS
AND DEWPOINTS IS NOT EXPECTED TO RAISE THE HEAT INDEX ABOVE ADVISORY
CRITERIA, BUT IT WILL STILL FEEL HOT, ESPECIALLY FRIDAY.
AS A NORTHERN STREAM UPPER TROF DEEPENS OVER THE NORTHEAST AND A
LOW CUTS OFF ACROSS THE MIDWEST, A SFC FRONT IS EXPECTED TO DRIFT
SOUTH INTO THE REGION ON SUNDAY. THE LATEST GUIDANCE SEEMS TO
HAVE MORE OF A SOUTHWARD PUSH WITH THE FRONT, BEING SOUTH OF THE
FCST AREA BY MONDAY MORNING AND THEN STAYING SOUTH AS WEAK HIGH
PRESSURE MOVES ACROSS THE NRN MID-ATLANTIC MONDAY THEN OFFSHORE
TUESDAY. THE SIGNAL FOR COLD AIR DAMMING SUNDAY INTO MONDAY LOOKS
WEAK ON THE NEW MODEL RUNS, SO CONFIDENCE IS RELATIVELY LOW WITH
THE HIGH TEMP FORECAST. WHETHER OR NOT A TRUE CAD UNFOLDS MIGHT
END UP BEING SEMANTICS, AS THERE SHOULD BE ENOUGH CLOUD COVER AND
A COOLER N/NE LOW LEVEL FLOW FROM THE WEAK HIGH TO THE NORTH TO
KEEP TEMPS ON THE COOL SIDE OF NORMAL. RIGHT NOW, OUR FORECAST
HIGHS FROM SUNDAY TO TUESDAY DROP DOWN INTO A RANGE 5-10 DEGREES
BELOW NORMAL. WITHOUT STRONG CAD SUPPORT, THE TEMPS MIGHT NOT
GET THAT COOL, THOUGH. EITHER WAY, GUIDANCE SUGGESTS THIS WILL BE
SHORT-LIVED AND THE TEMPS REBOUND BACK TO TYPICAL SUMMER HEAT BY
THE END OF THE WEEK.
KEY MESSAGE 2: MAINLY DIURNAL SHOWERS AND THUNDERSTORMS WILL BE MOSTLY
CONFINED TO WESTERN NORTH CAROLINA AGAIN TODAY WITH AN ISOLATED
SEVERE STORM POSSIBLE. COVERAGE IMPROVES FOR FRIDAY AND THE WEEKEND,
WITH BETTER CHANCES FOR LOOSELY ORGANIZED SEVERE WEATHER. THE RISK
FOR FLASH FLOODING OVER THE MOUNTAINS WILL INCREASE INTO THE EARLY
PART OF NEXT WEEK.
CONVECTIVE CLOUDS ARE DEEPENING AT THIS HOUR ACROSS THE FORECAST
AREA, WITH SHOWERS AND STORMS DEVELOPING OVER THE MTNS. THE
ENVIRONMENT ISN'T QUITE AS FAVORABLE FOR PULSE-SEVERE STORMS THIS
AFTERNOON AS THE SFC-BASED CAPE IS ONLY MODEST...ON THE ORDER OF
1500-2500 J/KG...BUT THE DCAPE SHOULD STILL BE ABOVE 800 J/KG
EAST OF THE MTNS. THUS, AN ISOLATED SEVERE WIND GUST PRODUCING
STORM WON'T BE RULED OUT. IN FACT, THE NEW DAY 1 OUTLOOK HAS AN
UPGRADE TO A MARGINAL RISK EAST OF THE MTNS. THAT BEING SAID,
THE CAMS HAVE MUCH BETTER-LOOKING STORMS WELL TO OUR NORTH. THE
STORMS SHOULD DIE OFF WITH THE LOSS OF HEATING THIS EVENING.
THE SITUATION MIGHT GET MORE INTERESTING THROUGH THE WEEKEND AS THE
GUIDANCE SUGGESTS SOMETHING OF AN MCS TRACK FROM THE MID-MS VALLEY
TO THE MID-ATLANTIC STARTING ON FRIDAY. A FEW MEMBERS OF THE 12Z
HREF SHOW AN MCS COMING ACROSS THE MID-MS VALLEY LATER THIS EVENING
AND THEN TOWARD US OVERNIGHT, THEN IT WOULD REMAIN TO BE SEEN HOW
LONG/FAR EAST IT COULD SURVIVE. IF THE SYSTEM FORMS, IT COULD AT
A MINIMUM LEAVE BEHIND AN MCV FOR OUTFLOW THAT WOULD BE A TRIGGER
FOR MORE STORMS TO DEVELOP OVER OUR REGION ON FRIDAY. ANOTHER
MCS COULD DO THE SAME ON FRIDAY NIGHT AND HAVE A BETTER CHANCE
FOR SURVIVAL ALL THE WAY EAST INTO THE MOUNTAINS. THERE IS MUCH
UNCERTAINTY AND WE LOOK TO UPCOMING MODEL RUNS FOR CLARITY. PRECIP
PROBS HAVE BEEN MODIFIED ONLY SLIGHTLY AND WILL START TO RELAX THE
DIURNAL TENDENCY. THE MAIN CONCERN WITH STORMS WILL BE DAMAGING
WIND GUSTS FRIDAY AND SATURDAY, AND THE DAY 2 CONVECTIVE OUTLOOK
ALREADY FEATURES AN EXPANSION OF THE MARGINAL RISK ACROSS THE
FCST AREA. THE GREATER RISK WILL GRADUALLY SHIFT TO HEAVY RAIN AND
FLASH FLOODING INTO EARLY NEXT WEEK. SUNDAY SHOULD HAVE THE BEST
RAIN CHANCES AS THE FRONT SAGS SOUTHWARD, AND MOISTURE SHOULD BE
PLENTIFUL ENOUGH TO SUPPORT AN INCREASED RISK OF FLASH FLOODING,
BUT AGAIN DETAILS REMAIN SKETCHY. PRECIP CHANCES SHOULD DROP ONCE
THE FRONT MOVES FARTHER SOUTH ON TUESDAY.
AVIATION /00Z FRIDAY THROUGH TUESDAY/
AT KCLT AND ELSEWHERE: A FEW ISOLATED TO WIDELY SCATTERED SHOWERS
AND STORMS CONTINUE TO LINGER ACROSS THE AREA EARLY THIS EVENING.
THIS ACTIVITY WILL GRADUALLY SHIFT EAST AND DISSIPATE OVER THE NEXT
SEVERAL HOURS WITH LITTLE TO NO IMPACT EXPECTED AT AREA TERMINALS.
QUIET CONDITIONS CONTINUE OVERNIGHT WITH LESS CONFIDENCE IN ANY
MOUNTAIN VALLEY FOG, ESPECIALLY OUTSIDE OF THE LITTLE TENNESSEE
VALLEY. A BUSY DAY IS IN STORE FOR FRIDAY WITH A RETURN OF GUSTY
SOUTHWEST WINDS DURING THE AFTERNOON AND ANOTHER BOUT OF AFTERNOON
SHOWERS AND STORMS. COVERAGE OF CONVECTION IS EXPECTED TO BE GREATER
AND PROB30 GROUPS HAVE BEEN INTRODUCED AT ALL TERMINALS. ASSOCIATED
VISIBILITY AND CEILING RESTRICTIONS CAN BE EXPECTED WITH ANY STORMS.
CONVECTION MAY LINGER LONGER TOMORROW EVENING WITH ADDITIONAL
UPSTREAM ROUNDS BRINGING A SHOT FOR OVERNIGHT IMPACTS AS WELL.
OUTLOOK: BETTER COVERAGE OF SHRA/TSRA CONTINUES FOR ALL TERMINALS
SATURDAY INTO MONDAY AS MULTIPLE ROUNDS OF STORMS MOVE TOWARDS AND
ACROSS THE AREA. DRIER CONDITIONS SHOULD DEVELOP TUESDAY INTO
WEDNESDAY. LOW STRATUS AND/OR FOG WILL BE POSSIBLE EACH MORNING IN
THE MOUNTAIN VALLEYS AND IN LOCATIONS THAT SEE APPRECIABLE RAINFALL
THE PREVIOUS AFTERNOON/EVENING.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
PM/TW
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