608
FXUS62 KGSP 111923
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
323 PM EDT SAT JUL 11 2026
WHAT HAS CHANGED
UPDATED DETAILS ABOUT CONVECTIVE POTENTIAL THIS AFTERNOON AND
TONIGHT. TEMPERATURES HAVE TRENDED LOWER FOR MONDAY AND TUESDAY
AND PRECIP CHANCES HAVE INCREASED BOTH OF THOSE DAYS.
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.
WE REMAIN UNDER A WESTERLY FLOW REGIME ALOFT, BETWEEN A DIGGING
TROUGH OVER THE NE QUADRANT OF THE CONUS AND THE BROAD SUBTROPICAL
RIDGE. A SLOW-MOVING COLD FRONT IS PRESENT SOUTH OF THE TROUGH. DEEP
UPPER ANTICYCLONE OVER THE DESERT SOUTHWEST WILL BUILD NORTH OVER
THE ROCKIES AND PLAINS THROUGH EARLY MONDAY. DOWNSTREAM OF THAT
RIDGE AND ALONG/SOUTH OF THE SFC FRONT, SEASONABLY HIGH CAPE IN
THE MID-MS VALLEY HAS ALLOWED MCSS TO DEVELOP EACH OF THE LAST
COUPLE OF EVENINGS, AND WITH THE PATTERN ALLOWING 0-3KM SHEAR OF
15-25 KT IN AN AREA OF WEAK WARM ADVECTION, THOSE MCSS HAVE BEEN
ABLE TO SURVIVE TO THE NC MOUNTAINS. OUTFLOW FROM THIS MORNING'S
ROUND OF UPSTREAM CONVECTION HELPED DRIVE STRONG TO SEVERE STORM
CLUSTERS OVER GA/SC EARLIER TODAY, BUT THAT ACTIVITY HAS SHIFTED
SOUTH. CONVECTIVE DEBRIS CLOUDS HAVE NOW CLEARED OVER PARTS
OF WESTERN NC AND IT REMAINS POSSIBLE SOME REDEVELOPMENT WILL
OCCUR THERE. CERTAINLY CANNOT RULE OUT REDEVELOPMENT IN GA/SC,
THOUGH THE NEWER COLD POOL AND TRACK OF EXTANT ACTIVITY TO OUR
WEST SUGGESTS THAT PORTION OF THE AREA IS MORE LIKELY TO REMAIN
SETTLED THIS AFTERNOON AND EARLY EVENING. WHEREVER STORMS DO FIRE
ALONG OUTFLOWS, GIVEN THE SHEAR, THE CELLS ARE LIKELY TO ORGANIZE
INTO CLUSTERS AND POSE A RISK OF DAMAGING WINDS. SPC UPGRADED
MUCH OF THE AREA TO A SLIGHT RISK ON THIS MORNING'S DAY 1 UPDATE,
BUT THE ASSOCIATED THREAT LIKELY HAS PEAKED FOR MOST OF THE SLIGHT
RISK AREA, PERHAPS EXCLUDING OUR FAR SOUTH.
TONIGHT, A WELL DEVELOPED 500MB CIRCULATION EMBEDDED IN A DEEP
SHORTWAVE NOW OVER MO/IL WILL DRIFT SOUTHEAST INTO THE LOWER OH
AND TN VALLEYS, WHILE THE FRONT OOZES SOUTHWARD ALSO. THE GENERAL
PATTERN SUPPORTING NOCTURNAL MCSS THUS CONTINUES, BUT THEY LOOK TO
INITIATE A LITTLE FURTHER SOUTH THAN THE PREVIOUS COUPLE OF DAYS,
STILL MAKING A RUN TO THE SOUTHEAST BUT POSSIBLY EVEN MISSING OUR
CWA. THE COLD FRONT WILL HOWEVER ARRIVE FROM THE NORTH DURING
THE DAY SUNDAY, INDUCING COOLER TEMPERATURES ESPECIALLY IN THE
NORTHERN CWA, BUT ENCOUNTERING A STILL VERY HUMID AIRMASS. THE
SHORTWAVE ALSO APPEARS TO PROVIDE SOME DPVA DURING THE AFTERNOON
SUCH THAT NUMEROUS TO WIDESPREAD SHOWERS/STORMS ARE EXPECTED TO
DEVELOP AGAIN...ASSUMING OUTFLOWS DON'T SPOIL THE SHOW. 0-3KM AND
0-6KM SHEAR IS ALSO IMPROVED AS A RESULT FURTHER INCREASING THE
POTENTIAL FOR ORGANIZED STORMS. THE CWA IS IN SPC MARGINAL RISK
FOR DAY 2, BUT A SLIGHT RISK IS NOW INCLUDED FOR THE SOUTHEAST
ZONES WHERE THE BEST OVERLAP OF FORCING/SHEAR ARE SEEN.
MODELS SEEM TO BE TRENDING MORE IN FAVOR OF THE COLD FRONT SLOWING
DOWN SUNDAY NIGHT INTO MONDAY DUE TO THE INFLUENCE OF THE SHORTWAVE,
WHICH BY THAT TIME LIKELY WILL HAVE A CLOSED CIRCULATION AS LOW
AS 850MB AND A WEAK SFC REFLECTION AS WELL. A PERIOD OF ENHANCED
EASTERLY 925-850MB WINDS CONTINUES TO BE EXPECTED ALONG THE FRONT IN
THAT TIME PERIOD, SO SOME TRAINING OF ELEVATED CONVECTION REMAINS
POSSIBLE ALONG IT, BUT SOUTHERLY LOW-LEVEL FLOW IS AN ADDITIONAL
CONCERN FOR ANCHORED CELLS NEAR THE BLUE RIDGE ESCARPMENT. CLOUDS
AND PRECIP WILL KEEP TEMPS BELOW NORMAL MONDAY, THOUGH THE MOISTURE
PLUME ALONG THE FRONT APPEARS LIKELY TO STILL BE OVER THE AREA
AND SO THE THREAT OF AT LEAST HEAVY RAINFALL WILL CONTINUE. WPC
DAY 2 SLIGHT FOR SUNDAY AND SUNDAY NIGHT, AND MARGINAL FOR DAY 3
(MON-MON NIGHT), BUT IF SOILS BECOME SATURATED AND MODELS REMAIN
CONSISTENT IN THIS SLOWER SOLUTION, COULD SEE MONDAY'S OUTLOOK
BEING UPGRADED AT SOME POINT. THE SLOWER TREND IS ALREADY REFLECTED
IN POPS NOW HAVING BEEN RAISED TO LIKELY OVER MOST OF THE SW
HALF OF THE CWA ON TUESDAY, WITH THE MOIST EASTERLY FLOW REGIME
LIKELY STILL IN PLACE THERE, WITH TEMPS ALSO STILL COOLER AND
PEAKING 7-10 BELOW NORMAL.
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.
BY LATE TUESDAY A REX BLOCK APPEARS TO SET UP OVER THE CONUS AS
THE ANOMALOUSLY DEEP UPPER RIDGE EXPANDS ACROSS THE NORTHERN TIER
AND THE REMNANT UPPER LOW RETROGRADES BENEATH IT. SO WHILE IT IS
NOT EXACTLY LOOKING LIKE A TYPICAL JULY PATTERN AT THAT TIME,
DRYING DOES APPEAR TO OCCUR SUCH THAT TEMPERATURES TREND BACK
NEAR NORMAL BY WEDNESDAY WITH SEASONABLY WEAK FLOW ALOFT. ANOTHER
TROUGH MAY DIG EAST OF THE RIDGE LATER IN THE WEEK, SETTING UP A
TREND TOWARD NW FLOW AGAIN. CONFIDENCE IS LOWER THAN NORMAL BUT
IT WOULD APPEAR OUR SENSIBLE WEATHER RETURNS TO SOMETHING CLOSER
TO USUAL MIDSUMMER, AS TEMPS WARM BACK TO NEAR OR ABOVE NORMAL
AND POPS ARE HIGHEST OVER THE MOUNTAINS.
AVIATION /19Z SATURDAY THROUGH THURSDAY/
AT KCLT AND ELSEWHERE: CONVECTIVE OUTFLOWS HAVE PUSHED PAST ALL THE
TERMINALS ALREADY TODAY AND IT APPEARS SLIGHTLY MORE LIKELY THAN
NOT THAT WILL PRECLUDE DEVELOPMENT OF ANY MORE SHRA/TSRA THROUGH
SUNSET. HOWEVER, THERE IS TIME FOR AT LEAST MODEST DESTABILIZATION
TO OCCUR AS CONVECTIVE REMNANT CLOUDS CLEAR THIS AFTERNOON, AND
THERE REMAIN WEAK DISTURBANCES ALOFT THAT COULD HELP SOME CLUSTERING
OF STORMS. KAVL ONLY HAS VCSH, KCLT/KHKY HAVE PROB30, AND THE SC
SITES HAVE A TEMPO, WITH KGSP/KGMU POTENTIALLY STILL HAVING VCTS
AS STORMS DRIFT FURTHER AWAY FROM THE AREA. THE OUTFLOWS TURNED
WINDS NW'LY AT KCLT AND THE SC SITES, BUT AS THE OUTFLOW MIXES OUT
WINDS SHOULD AGAIN FAVOR WSW WITH TIME THIS AFTERNOON. IF STORMS
REDEVELOP THERE, THEY MOST LIKELY WOULD APPROACH FROM THE SW SO
THE AFTERNOON PROB30 INCLUDES G30KT FROM THAT DIRECTION.
WINDS WILL BE LIGHTER TONIGHT COMPARED TO FRI NIGHT, AND CROSSOVER
TEMPERATURES ARE EXPECTED TO BE HIGHER, SO THERE IS SOMEWHAT
HIGHER POTENTIAL FOR DAYBREAK FOG/STRATUS. KCLT AND KAVL BOTH
RETAIN A MENTION FOR FEW CLOUDS AT IFR LEVEL, BUT KAVL NOW HAS
MVFR VSBY. EXPECT THIS TO BE REEVALUATED ON THE 00 AND 06Z TAF
SETS. SIMILAR TO THU AND FRI NIGHTS, CONDITIONS TONIGHT WILL BE
FAVORABLE FOR STORM COMPLEXES TO DEVELOP UPSTREAM AND APPROACH
THE CAROLINAS. RECENT MODEL TRENDS SUGGEST THIS ACTIVITY IS NOT
LIKELY TO REACH THE TAF SITES WITH DIRECT TS IMPACTS, THOUGH
THE POTENTIAL REMAINS FOR COLD POOLS OR CLOUD COVER TO LIMIT TS
DEVELOPMENT DURING THE DAY SUNDAY. A BETTER DEFINED COLD FRONT
WILL HOWEVER ARRIVE FROM THE NORTH LATE IN THE DAY AND THAT,
AND/OR DIFFERENTIAL HEATING ALONG OUTFLOWS, COULD STILL LEAD TO
CLUSTERS OF STORMS DEVELOPING. CONFIDENCE REMAINS LOW, BUT ALL IN
ALL FELT A PROB30 AT KCLT WAS WARRANTED FOR SUN AFTN.
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.
JCW
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