186
FXUS62 KGSP 110703 CCA
AFDGSP
AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
300 AM EDT SAT JUL 11 2026
WHAT HAS CHANGED
NO SIGNIFICANT CHANGES AT THIS TIME.
KEY MESSAGES
1. VERY ACTIVE CONVECTIVE WEATHER IS EXPECTED TO CONTINUE THROUGH
EARLY NEXT WEEK. ISOLATED SEVERE STORMS AND LOCALIZED FLASH
FLOODING WILL BE POSSIBLE EACH DAY THROUGH MONDAY. OTHERWISE,
A COOLING TREND IS EXPECTED, WITH WELL-BELOW NORMAL TEMPERATURES
FORECAST BY MONDAY.
2. A RETURN TO SEASONABLY HOT CONDITIONS AND TYPICAL COVERAGE OF
DIURNAL SHOWERS AND STORMS IS EXPECTED DURING THE LATTER HALF OF
NEXT WEEK.
DISCUSSION
KEY MESSAGE 1: VERY ACTIVE CONVECTIVE WEATHER IS EXPECTED TO CONTINUE
THROUGH EARLY NEXT WEEK. ISOLATED SEVERE STORMS AND LOCALIZED
FLASH FLOODING WILL BE POSSIBLE EACH DAY THROUGH MONDAY. OTHERWISE,
A COOLING TREND IS EXPECTED, WITH WELL-BELOW NORMAL TEMPERATURES
FORECAST BY MONDAY.
CONVECTION IS ONGOING ACROSS THE REGION THIS MORNING, WITH SHOWERS
DEVELOPING ALONG A WEAK CONVERGENT AXIS FROM THE OHIO VALLEY INTO
FAR WESTERN NC. THE CONVERGENT AXIS IS MORE OR LESS PARALLEL TO
THE MEAN FLOW...SO SOME DEGREE OF CELL TRAINING WAS BEGINNING TO
SET UP IN THE VICINITY OF I-26 NEAR THE TN/NC BORDER. IT APPEARS
THAT RAINFALL RATES WILL BE RATHER TAME IN THE SHORT TERM...BUT
IF THIS TREND CONTINUES FOR MORE THAN A COUPLE OF HOURS...A LOW END
FLASH FLOOD THREAT COULD DEVELOP ACROSS THE NC MOUNTAINS AS THE
MORNING PROGRESSES.
OVERALL, HOW CONVECTIVE TRENDS WILL EVOLVE THROUGHOUT THE DAY
IS ABOUT AS CLEAR AS MUD AT THIS JUNCTURE, AS IN ADDITION TO
THE ONGOING ACTIVITY ACROSS OUR AREA, THERE ARE MULTIPLE AREAS OF
LOOSELY ORGANIZED SHOWERS AND STORMS CURRENTLY STRETCHING FROM THE
WESTERN OHIO VALLEY INTO THE SOUTHERN GREAT PLAINS. THESE AREAS OF
CONVECTION WILL LIKELY APPROACH THE SOUTHERN APPALACHIANS AND
VICINITY THROUGHOUT THE DAY...AS AN AREA OF HEIGHT FALLS DIVES FROM
THE CORN BELT EARLY THIS MORNING...TO THE TN VALLEY TONIGHT. THE
EXTENT OF ANY SEVERE STORM THREAT TODAY WILL DEPEND LARGELY UPON HOW
THIS UPSTREAM ACTIVITY EVOLVES THROUGH THE MORNING...AND THE EXTENT
(IF ANY) TO WHICH IT IS ABLE TO INHIBIT DESTABILIZATION LATER TODAY.
BASED UPON THE LATEST MESOANALYSIS, CONVECTION IS GOING TO STRUGGLE
TO MAKE MUCH INROADS INTO THE CWA THIS MORNING, AS MUCAPE FALLS OFF
SIGNIFICANTLY (< 500 J/KG) EAST OF THE BLUE RIDGE. WE THEREFORE
SUSPECT THE PIEDMONT AND FOOTHILLS SHOULD MODERATELY DESTABILIZE
THIS AFTERNOON, WITH MCV'S AND/OR OUTFLOWS/DIFFERENTIAL HEATING
BOUNDARIES LEFT BEHIND BY UPSTREAM CONVECTION PROVIDING THE LIFT TO
INTERACT WITH THIS INSTABILITY AND PRODUCE GOOD COVERAGE OF SHOWERS
AND STORMS ACROSS THE AREA THIS AFTERNOON INTO THE EVENING...WITH
MULTIPLE ROUNDS OF CONVECTION POSSIBLE AS ACTIVITY FARTHER UPSTREAM
APPROACHES THE AREA.
WHILE DEEP LAYER SHEAR IS FORECAST TO REMAIN WEAK, LOW LEVEL
SHEAR OF 15-20 KTS WILL CONTINUE TO SUPPORT SOME DEGREE OF COLD
POOL-CLUSTERING THAT WILL POSE SOME THREAT OF STRONG-TO-DAMAGING
DOWNBURSTS. THE THREAT FOR ISOLATED FLASH FLOODING WILL ALSO
PERSIST THROUGH THE DAYLIGHT HOURS, ESPECIALLY ACROSS THE FAR
WESTERN MOUNTAINS...THE AREA WHICH STANDS THE BEST CHANCE OF SEEING
MULTIPLE ROUNDS OF HEAVY RAIN SHOWERS AND STORMS. OTHERWISE, ONE
MORE DAY OF ABOVE NORMAL TEMPERATURES IS EXPECTED TODAY BEFORE
COOLER CONDITIONS EVOLVE EARLY NEXT WEEK. A FEW SPOTS ACROSS
THE SOUTHERN TIER OF FORECAST ZONES AND THE CHARLOTTE METRO AREA
COULD BRIEFLY SEE HEAT INDEX IN THE 101-103 RANGE THIS AFTERNOON,
BUT NOTHING WORTHY OF ANY HEAT HEADLINES.
CONVECTION-ALLOWING AND SHORT TERM MODEL GUIDANCE AGREE THAT A
RELATIVE LULL IN THE CONVECTIVE ACTIVITY WILL OCCUR TONIGHT, BEFORE
ANOTHER ROUND OF FAIRLY WIDESPREAD CONVECTION DEVELOPS SUNDAY...AS
AN UPPER LOW BEGINS TO CLOSE OFF OVER THE TN VALLEY. INCREASED
CLOUD COVER AND SLIGHTLY LOWER HEIGHTS ARE FORECAST TO YIELD ONE
OF THE FEW NEAR-NORMAL TEMPERATURE DAYS WE'VE SEEN OVER THE PAST
COUPLE OF WEEKS. THIS WILL RESULT IN SLIGHTLY LOWER INSTABILITY. IN
TERMS OF THE SEVERE WEATHER THREAT, THE LOWER BUOYANCY MAY BE
SOMEWHAT OFFSET BY A BRIEF INCREASE IN DEEP LAYER SHEAR SUNDAY
AFTERNOON...SO ANOTHER MARGINAL RISK IS APPROPRIATE.
BY LATE SUNDAY, A SLOW-MOVING BACK DOOR COLD FRONT IS EXPECTED
TO BEGIN MOVING INTO THE CWA FROM THE NE...ALTHOUGH UNCERTAINTY
ABOUT HOW FAR SW IT WILL PUSH REMAINS HIGH...OWING TO POTENTIAL
DEVELOPMENT OF WEAK LOW PRESSURE ACROSS THE REGION. IN ASSOCIATION
WITH THIS BOUNDARY, ESE UPSLOPE FLOW IS FORECAST TO DEVELOP
ACROSS AT LEAST THE NORTHERN PART OF THE AREA. ALL THIS AS THE
FLOW ALOFT WEAKENS WITHIN A COL REGION ON THE EAST SIDE OF THE
UPPER LOW. THESE FACTORS SPELL POTENTIAL FOR SLOW-MOVING AND/OR
TRAINING CELLS...WITHIN AN ENVIRONMENT CHARACTERIZED BY PWATS OF
AROUND 2 INCHES AND WARM CLOUD DEPTHS WELL OVER 10 KFT. THE FLASH
FLOOD THREAT THEREFORE MAY SEE A BIT OF AN UPTICK IN THE LATE SUNDAY
THROUGH MONDAY TIME FRAME...ALTHOUGH INSTABILITY WILL INCREASINGLY
BECOME A LIMITING FACTOR BY MONDAY, AS EXTENSIVE CLOUD COVER AND
NE FLOW HOLDS HIGH TEMPS WELL BELOW CLIMO.
KEY MESSAGE 2: A RETURN TO SEASONABLY HOT CONDITIONS AND TYPICAL
COVERAGE OF DIURNAL SHOWERS AND STORMS IS EXPECTED DURING THE LATTER
HALF OF NEXT WEEK.
WEAKLY CYCLONIC UPPER FLOW EARLY IN THE WEEK IS FORECAST TO GIVE WAY
TO RISING HEIGHTS AND THE RETURN OF RIDGING ALOFT BY THE MIDDLE OF
NEXT WEEK, AS AN ANTICYCLONE CENTERED OVER THE NORTHERN GREAT
PLAINS/ UPPER MISS VALLEY GETS SQUEEZED FROM THE SOUTH AND BROADENS.
PRIOR TO THIS PATTERN CHANGE, CONVECTIVE CHANCES REMAIN SOMEWHAT
ELEVATED TUESDAY, BUT BY WED...A MORE TYPICAL REGIME OF WIDELY
SCATTERED MOUNTAIN CONVECTION...WITH ISOLATED COVERAGE ELSEWHERE IS
EXPECTED...WITH THAT TREND GENERALLY FORECAST TO CONTINUE THROUGH
THE END OF THE WEEK. TEMPERATURES ARE FORECAST TO REMAIN SEVERAL
DEGREES BELOW CLIMO TUESDAY BEFORE WARMING TO NEAR-NORMAL WED...THE
N ENDING THE WEEK A COUPLE OF DEGREES ABOVE CLIMO.
AVIATION /07Z SATURDAY THROUGH WEDNESDAY/
AT KCLT AND ELSEWHERE: SCATTERED SHOWERS ALONG WITH A STRAY
THUNDERSTORM ARE EXPECTED TO CONTINUE DEVELOPING ACROSS THE TN
VALLEY AND SOUTHERN APPALACHIANS EARLY THIS MORNING. A FEW OF
THESE MAY DRIFT TOWARD KAVL...ESPECIALLY TOWARD THE PRE-DAWN HOURS,
AND A VCSH IS CARRIED DURING THAT TIME FRAME. OTHERWISE, THE MOST
IMMEDIATE CONCERN WILL BE THE POTENTIAL FOR LOW STRATUS AND/OR
FOG IN LIGHT OF THE WIDESPREAD RAIN THAT FELL ACROSS THE TERMINAL
FORECAST AREA YESTERDAY AFTERNOON/EVENING. IN GENERAL...PERSISTENT
WSW WINDS OF 4-6 KTS ARE EXPECTED TO PRECLUDE SIGNIFICANT FOG
POTENTIAL AT THE UPSTATE SC TERMINALS AND KCLT...BUT THERE'S
ENOUGH OF A CHANCE OF STRATUS DEVELOPMENT TO INTRODUCE TEMPOS
FOR FEW/SCT IFR CLOUD LAYERS AT THOSE SITES. CONDITIONS APPEAR TO
BE MORE FAVORABLE FOR RESTRICTIONS AT KAVL AND ESPECIALLY KHKY,
AND PREVAILING MVFR/TEMPO IFR VISBY HAS BEEN INTRODUCED AT THOSE
SITES BY DAYBREAK.
THE CONVECTIVE PICTURE FOR LATER TODAY IS SOMEWHAT MUDDIED BY
MULTIPLE AREAS OF SOMEWHAT ORGANIZED UPSTREAM CONVECTION THAT COULD
MAKE A RUN TOWARD THE AREA AS EARLY AS SUNRISE-ISH. PROB30S FOR TSRA
BEGIN AS EARLY AS 13Z AT KAVL, AND 16-18Z AT THE OTHER TAF SITES. A
TEMPO FOR TSRA IS INCLUDED AT KAVL DURING THE AFTERNOON. PROB30S ARE
LIKELY TO BE EVENTUALLY CONVERTED TO TEMPOS AT THE OTHER SITES, BUT
THIS WILL NEED TO WAIT UNTIL CONFIDENCE IN TIMING IMPROVES. WINDS
WILL REMAIN OUT OF THE WSW...INCREASING TO AROUND 10 KTS AT MOST
SITES BY EARLY AFTERNOON.
OUTLOOK: GREATER THAN NORMAL COVERAGE OF SHRA/TSRA WILL CONTINUE
ACROSS OUR AREA SUNDAY INTO MONDAY AS MULTIPLE ROUNDS OF STORMS
ARE EXPECTED ACROSS THE REGION. DRIER CONDITIONS SHOULD DEVELOP
TUESDAY INTO WEDNESDAY. LOW STRATUS AND/OR FOG WILL BE POSSIBLE EACH
MORNING IN THE MTN VALLEYS AND IN LOCATIONS THAT SEE APPRECIABLE
RAINFALL THE PREVIOUS AFTERNOON/EVENING.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
JDL
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