455
FXUS62 KGSP 140549
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
149 AM EDT MON JUL 14 2025
SYNOPSIS
A TYPICALLY ACTIVE MID-SUMMER WEEK IS AHEAD AS DAILY THUNDERSTORM
CHANCES CONTINUE. A FEW STORMS COULD PRODUCE DAMAGING WIND GUSTS
AND LOCALIZED FLASH FLOODING MAY DEVELOP FOLLOWING HEAVY RAINFALL.
DAILY HIGH TEMPERATURES WILL BE SEVERAL DEGREES ABOVE NORMAL TODAY,
TREND BACK TO AROUND NORMAL TUESDAY THROUGH THURSDAY, THEN TREND
WARMER AGAIN.
NEAR TERM /THROUGH TONIGHT/
AS OF 145 AM EDT MONDAY: LINGERING CONVECTION ACROSS THE WESTERN
PIEDMONT OF NORTH CAROLINA HAS DISSIPATED, LEAVING CONVECTIVE
DEBRIS IN THE AREA. OTHERWISE, ANOTHER MUGGY NIGHT IS IN STORE
WITH MOUNTAIN VALLEY FOG EXPECTED ONCE AGAIN.
THE MID- TO UPPER-LEVEL RIDGE OVER THE SOUTHEASTERN CONUS WILL
FLATTEN OUT AS A WEAK SHORTWAVE SLIPS NORTH OF THE CFWA DURING THE
DAYTIME PERIOD. EXPECT THE COVERAGE IN CONVECTION TO UPTICK COMPARED
TO SUNDAY WITH INITIATION LIKELY TO START ACROSS THE MOUNTAINS AND
SPREAD EAST INTO THE FOOTHILLS AND PIEDMONT LATER IN THE AFTERNOON
AND EVENING. CAMS SUPPORT THE IDEA OF OUTFLOW/COLD POOL DRIVEN
ORGANIZATION AS THE ACTIVITY GETS GOING WITH AN ENVIRONMENT OF 2000-
3000 J/KG OF SBCAPE, 800-1200 J/KG OF DCAPE, AND <20 KTS OF DEEP
LAYER SHEAR. THIS SUGGEST THAT STRONG TO SEVERE STORMS ARE STILL
PRESENT WITH WET MICROBURSTS AS THE PRIMARY THREAT, TO GO ALONG WITH
A LOCALIZED FLASH FLOOD THREAT AS A PWAT VALUES REMAIN HIGH (1.50"-
2.00"). THERE IS SOME SPECULATION THAT CONVECTION WON'T HAVE A
TYPICAL DIURNAL TREND AND MAY LINGER LATE IN THE EVENING INTO THE
EARLY PORTIONS OF THE OVERNIGHT. AFTERNOON HIGHS WILL REMAIN A FEW
TICKS ABOVE NORMAL, BUT DEWPOINTS SHOULD MIX OUT ENOUGH TO KEEP HEAT
INDEX VALUES JUST BELOW ADVISORY CRITERIA. LINGERING CONVECTION AND
DEBRIS WILL BE EVIDENT TO START OUT THE OVERNIGHT PERIOD WITH A
GRADUAL DISSIPATION. ANOTHER MUGGY NIGHT WITH OVERNIGHT LOWS RUNNING
A FEW TICKS ABOVE NORMAL, WHILE AREAS OF LOW STRATUS AND FOG CAN'T
BE RULED OUT, ESPECIALLY IN THE MAJOR MOUNTAIN VALLEYS.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/
AS OF 1215 AM MON: SHORTWAVE ASSOCIATED WITH CANADIAN SYSTEM, WITH
TRAILING WEAK COLD FRONT, WILL MOVE OFF THE EAST COAST TUESDAY.
MEANWHILE, A BAGGY TROUGH IN THE MID-MS VALLEY, FORMERLY A CUTOFF
LOW, WILL DRIFT NORTHEAST AND STALL AND/OR REVERSE THE FRONTAL
BOUNDARY. THIS LOOKS TO PREVENT US FROM EXPERIENCING TRUE AIRMASS
CHANGE VIA THE FRONT. INVERTED TROUGH HOWEVER TRACKING ACROSS
FLORIDA WILL REINFORCE SOUTHEASTERLY LOW-LEVEL FLOW. SOME SEMBLANCE
OF A CONVERGENCE AXIS COULD RESULT WITH THE TROUGH, BUT A CLEAR
SIGNAL IS SEEN AMONG MODELS FOR SEA-BREEZE FRONT TO ADVECT INTO THE
CWA IN THE LATE AFTERNOON OR EVENING. ALTHOUGH TEMPS TREND SLIGHTLY
COOLER UNDER REDUCED THICKNESSES, MUGGY DEWPOINTS WILL MAINTAIN
RELATIVELY LOW LCLS; IN ADDITION TO THE USUAL DIURNAL FORCING, THE
POTENTIAL FOR ENHANCED CONVERGENCE SUGGESTS ABOVE-CLIMO POPS ONCE
AGAIN, DECLINING SLOWLY TUESDAY NIGHT GIVEN THE POTENTIAL FOR
LINGERING SEA BREEZE ACTIVITY. THE PATTERN REALLY DOESN'T CHANGE
MUCH FOR WEDNESDAY, ALTHOUGH THE GFS AND EC VEER LOW-LEVEL FLOW
SLIGHTLY MORE TOWARD THE SW, WHICH COULD SUGGEST MORE
TYPICAL/CLIMATOLOGICAL POP TRENDS. HOWEVER, THE NAM AND GDPS
MAINTAIN AN EASTERLY COMPONENT TO VERY LOW LEVEL WINDS AND
ACCORDINGLY SUGGEST A SECOND DAY OF SEA BREEZE CONVECTION.
THICKNESSES TREND SLIGHTLY LOWER WEDNESDAY FOR MAX TEMPS A WEE BIT
COOLER BUT STILL ABOUT NORMAL. BOTH DAYS, DEWPOINTS WILL REMAIN A
BIT HIGHER THAN NORMAL AND HEAT INDEX SHOULD PUSH PAST 100 IN AREAS
OF THE PIEDMONT, BUT BELOW HEAT ADVISORY CRITERIA. THUNDERSTORMS
APPEAR TO POSE SEASONABLE, GENERALLY LOCALIZED THREATS OF WET
MICROBURSTS AND TORRENTIAL RAINFALL, WHICH COULD RESULT IN A FEW
INSTANCES OF WIND DAMAGE AND FLASH FLOODING EACH DAY.
LONG TERM /THURSDAY THROUGH SUNDAY/
AS OF 115 AM MON: A WEAKNESS PERSISTS IN THE UPPER PATTERN OVER THE
GULF COAST REGION AS THE WEAK TROUGH CONTINUES TO DRIFT WEST. A FAIR
NUMBER OF MEMBERS OF EACH GLOBAL ENSEMBLE DEPICT FORMATION OF A
SURFACE LOW IN THE GULF, WHICH GENERALLY IS SHOWN TO DRIFT ONSHORE
INVOF LOUISIANA THURSDAY OR EARLY FRIDAY. HENCE NO DIRECT IMPACT OF
ANY SUCH LOW IS EXPECTED HERE. MORE OR LESS TYPICAL DIURNAL POPS ARE
EXPECTED THURSDAY ALTHOUGH COVERAGE MAY STILL BE A BIT HIGHER THAN
CLIMO OWING TO ELEVATED DEWPOINTS. A GRADUAL WARMING TREND IS
EXPECTED FOR THE CWA THURSDAY THRU SATURDAY AS THE BERMUDA HIGH
RETROGRADES OVER THE SOUTHEAST COAST, BUT THE LOWER HEIGHTS
SURROUNDING THE LOW MAY MITIGATE THE WARMING TO SOME EXTENT. A BROAD
SHORTWAVE TROUGH ASSOCIATED WITH THE NEXT FRONTAL SYSTEM SHOULD PASS
THE CENTRAL AND NORTHERN APPALACHIAN CHAIN CIRCA FRIDAY, WHICH COULD
BRING THE FRONT AS FAR SOUTH AS NC. AS RIDGE BUILDS TO OUR WEST OR
SOUTHWEST BEHIND THE DISSIPATING GULF TROUGH/LOW, THE FRONT MAY
PIVOT AND COULD EFFECTIVELY STALL OVER THE CWA INTO NEXT WEEKEND.
AS A RESULT POPS TREND SLIGHTLY HIGHER AGAIN FOR FRI-SUN WITH A
SLOWER THAN USUAL NOCTURNAL DECLINE SAT AND SUN NIGHTS. SHEAR DOES
NOT INCREASE APPRECIABLY; WEAK STEERING FLOW WILL CONTINUE AND COULD
ORIENT PARALLEL TO THE FRONT, SO HEAVY RAINFALL AND LOCALIZED FLASH
FLOODING PROBABLY WILL BE A DAILY CONCERN PARTICULARLY WHERE SOILS
SATURATE FOLLOWING REPEATED ROUNDS OF SHOWERS/STORMS OVER THE COURSE
OF THE WEEK. HEAT INDEX STILL IS FORECAST TO PEAK AT 100 TO 105 IN
THE WARMER PIEDMONT AREAS FRI-SUN.
AVIATION /06Z MONDAY THROUGH FRIDAY/
AT KCLT AND ELSEWHERE: LINGERING CONVECTIVE DEBRIS SHOULD GRADUALLY
SCATTER OUT OVER THE NEXT COUPLE OF HOURS AS ANY SHOWERS AND
THUNDERSTORMS HAVE DISSIPATED. ALREADY SEEING MOUNTAIN VALLEY LOW
STRATUS/FOG WITH A FEW INSTANCES NEAR KAVL. AS A RESULT, PLACED A
TEMPO THROUGH DAYBREAK FOR LIFR VSBY AND CIG. KHKY RECEIVED HEAVY
RAINFALL WITH FOG ALREADY DEVELOPING UPSTREAM OVER THE NEARBY RIVER
BASIN, SO DECIDED TO PLACE A TEMPO FOR LIFR VSBY AND CIG THROUGH
DAYBREAK AS WELL. VFR CONDITIONS AT KCLT AND THE UPSTATE SITES
THROUGH THE MORNING HOURS. ANOTHER ROUND OF AFTERNOON AND EVENING
SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS THE AREA. PROB30 HAS
BEEN PLACED AT ALL TAF SITES WITH ASSOCIATED RESTRICTIONS.
OTHERWISE, ANOTHER ROUND OF LOW STRATUS AND FOG WILL BE POSSIBLE
ACROSS THE TERMINALS OVERNIGHT, WITH THE BEST CHANCE AT KAVL AND
KHKY ONCE AGAIN. WINDS WILL BE LIGHT AND VARIABLE THROUGH MUCH OF
THE FORECAST PERIOD, BUT WILL FAVOR A NORTHWESTERLY DIRECTION.
OUTLOOK: TYPICAL SUMMERTIME WEATHER IS EXPECTED INTO EARLY NEXT
WEEK, WITH SCATTERED TO NUMEROUS THUNDERSTORMS MAINLY IN THE
AFTERNOON/EVENING AND FOG AND/OR LOW STRATUS POSSIBLE EACH MORNING.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
SYNOPSIS...WIMBERLEY
NEAR TERM...CAC
SHORT TERM...WIMBERLEY
LONG TERM...WIMBERLEY
AVIATION...CAC
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