842
FXUS62 KGSP 131738
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
138 PM EDT SUN JUL 13 2025
SYNOPSIS
A TYPICALLY ACTIVE MID-SUMMER WEEK IS AHEAD AS DAILY THUNDERSTORM
CHANCES CONTINUE. A FEW STORMS COULD PRODUCE DAMAGING WIND GUSTS,
PARTICULARLY MONDAY. DAILY HIGH TEMPERATURES WILL BE SEVERAL DEGREES
ABOVE NORMAL AT THE BEGINNING OF THE WEEK BUT TREND BACK TO AROUND
NORMAL TUESDAY THROUGH THURSDAY.
NEAR TERM /THROUGH MONDAY/
AS OF 1245 PM EDT SUNDAY: THE FCST APPEARS TO BE ON TRACK EARLY
THIS AFTERNOON. SATELLITE IMAGERY SHOWS EVIDENCE OF THE STRONGER
MID/UPPER RIDGE OVERHEAD. CONVECTIVE INITIATION HAS OCCURRED OVER
THE MOUNTAINS, MAINLY OVER THE HIGH ELEVATIONS OF THE BALSAMS,
BUT ALSO OVER THE SMOKIES AND NANTAHALA MOUNTAINS. THIS SHOULD
ALSO TAKE PLACE ELSEWHERE OVER THE HIGHER TERRAIN INTO THE
MIDDLE PART OF THE AFTERNOON. MEANWHILE...A LINGERING PATCH OF
MID-LEVEL CLOUDINESS WAS DELAYING THE WARMUP AND CONVECTION OVER
THE I-77 CORRIDOR. THE MORNING GUIDANCE CONTINUES TO SUPPORT THE
IDEA THAT COVERAGE OF STORMS WILL BE LESS THAN THE LAST FEW DAYS
AND THE PRECIP PROBS CONTINUE TO REFLECT THAT THINKING. IT'S NOT
FOR LACK OF BUOYANCY, WHICH WILL RANGE FROM 2000 TO 3000 J/KG OF
SFC-BASED CAPE, BUT FOR LACK OF TRIGGERS AND MORE MID-LEVEL DRY AIR
TO OVERCOME. THAT DRY AIR LAYER WILL PROVIDE FOR HIGHER DCAPE THAN
THE PREVIOUS FEW DAYS, GREATER THAN 800 J/KG ACROSS THE WHOLE AREA,
SO IN SPITE OF THE LACK OF A MARGINAL RISK ON THE DAY 1 OUTLOOK,
ANY STORMS THAT MANAGE TO REALLY GET GOING WILL HAVE MORE OF A
WET MICROBURST RISK THAN YESTERDAY. OUR FLASH FLOOD THREAT IS
RELATIVELY LESS, HOWEVER. NO NEED TO GIVE UP ON THE HIGH TEMP
FORECAST JUST YET. DEWPOINT SHOULD MIX OUT JUST ENOUGH TO KEEP
THE APPARENT TEMP BELOW HEAT ADVISORY CRITERIA.
ANY STORMS THAT MANAGE TO PERSIST INTO THE EARLY EVENING SHOULD
DIMINISH AN HOUR OR SO AFTER SUNSET. AFTER THAT, YET ANOTHER MUGGY
NIGHT WITH TEMPS ABOVE NORMAL, CLEARING SKY, AND A CHANCE OF MTN
VALLEY FOG IN THE PRE-DAWN HOURS.
FOR MONDAY, THE UPPER RIDGE OVER THE SOUTHEAST SHOULD FLATTEN AND
EXPAND AS THE WEAK UPPER WAVE TO OUR NW LIFTS OUT AND DEAMPLIFIES
QUICKLY AS IT PASSES WELL TO OUR NORTH THROUGH THE AFTERNOON. THIS
SUGGESTS A CONTINUANCE OF WHAT ESSENTIALLY AMOUNTS TO A SLIGHTLY
HIGHER THAN CLIMO PRECIP PROB ACROSS MOST OF THE AREA. THE MTNS ARE
THE EXCEPTION, WHERE PRECIP PROBS WILL GO INTO THE LIKELY RANGE,
MOSTLY BECAUSE OF THE HRRR SUGGESTION OF SOME BETTER COVERAGE
AND ORGANIZATION ALONG A POSSIBLE OUTFLOW BOUNDARY, FROM PREVIOUS
CONVECTION, THAT REACHES THE MTNS DURING AFTERNOON HEATING. PROFILES
LOOK TALL AND SKINNY AND MID-LEVEL DRY AIR IS NOT AS PRONOUNCED
ON FCST SOUNDINGS, SO PERHAPS OUR SEVERE THREAT WILL TREND BACK
DOWN. AS FOR TEMPS...IT LOOKS LIKE ANOTHER HOT ONE...BUT WITH
DEWPOINTS MIXING OUT ENOUGH AGAIN TO KEEP THE APPARENT TEMP BELOW
ADVISORY CRITERIA IN THE AFTERNOON.
SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/
AS OF 1155 AM SUNDAY: THE UPPER RIDGE AXIS IS PROGGED REMAIN ATOP
THE CWFA THROUGH THE PERIOD WHILE CONTINUED SOUTHERLY FLOW AROUND
BERMUDA HIGH PRESSURE ADVECTS HIGHER PWAT VALUES INTO THE REGION,
WHICH SEEM TO BE TROPICAL IN NATURE ORIGINATING CLOSER TO THE WWD
MOVING INVERTED TROUGH. DESPITE THE UPPER RIDGE POSITIONING, GIVEN
BROAD SOUTHERLY LLVL CONVERGENCE AND RICHER MOISTURE, DIURNALLY
ENHANCED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO BECOME NUMEROUS
EACH DAY WITH LOCALLY EXCESSIVE RAINFALL ON ONGOING THREAT. WE WILL
BE STEPPING AWAY MONDAY'S PIEDMONT MAXIMUM MIDDLE 90S PROGGING
VALUES CLOSER TO CLIMO TUESDAY AND WEDNESDAY, BUT SFC DWPTS WILL
WIND UP BEING HIGHER WITH LESS CHANCES OF DOWNWARD MIXING.
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/
AS OF 1230 PM SUNDAY: THE CWFA STILL LOOKS TO BE WITHIN THE
PERIPHERY OF THE CIRCULATION AROUND BERMUDA HIGH PRESSURE TO START
OFF THE PERIOD WITH THE DETERMINISTIC GFS/ECMWF BOTH REBUILDING THE
CENTER OF STRONG UPPER ANTICYCLONE BACK ATOP THE REGION FOR FRIDAY.
SO, DAILY MAXIMUMS WILL CREEP BACK UPWARD TO ABOVE CLIMO BY FRIDAY.
POTENTIALLY WIDESPREAD DEEP CONVECTION ON THURSDAY MAY TREND BACK TO
CLIMO POP ON FRIDAY IF RIDGE IN FACT DOES BUILD AS PROGGED. THE
MEDIUM RANGE MODELS ARE HINTING THAT UPPER RIDGE CENTRAL WILL SHIFT
WWD OVER NEXT WEEKEND, BUT AT THIS POINT, SENSIBLE WX WILL BE
TYPICAL FOR MID-JULY FOR SATURDAY AND SUNDAY.
AVIATION /18Z SUNDAY THROUGH FRIDAY/
AT KCLT AND ELSEWHERE: VFR AT ALL TERMINALS THRU EVENING AWAY
FROM THUNDERSTORMS. COVERAGE OF CONVECTION SHOULD BE LESS THAN THE
PAST FEW DAYS, SO TAFS ARE LIMITED TO PROB30S AND WILL BE AMENDED
BASED ON RADAR TRENDS LATER THIS AFTERNOON. WIND WILL BE LIGHT
NW OR VARIABLE. AFTER SUNSET, ONLY CONVECTIVE CLOUD DEBRIS WILL
REMAIN. LOW CONFIDENCE IN LOW STRATUS/FOG AT KAVL OVERNIGHT BASED
ON RECENT MODEL PERFORMANCE, BUT WILL INCLUDE AT LEAST A TEMPORARY
RESTRICTION FOR NOW. FOR MONDAY, ANOTHER AFTERNOON STORM CHANCE
SIMILAR TO TODAY, SO ONLY KCLT WILL GET THE PROB30 RIGHT NOW
BECAUSE OF THE 30 HR PERIOD. WIND WILL BE LIGHT/VARIABLE THANKS
TO WEAK HIGH PRESSURE.
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...CSH
NEAR TERM...PM
SHORT TERM...CSH
LONG TERM...CSH
AVIATION...PM
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page