298
FXUS62 KGSP 291058
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
658 AM EDT WED JUL 29 2026
WHAT HAS CHANGED
NO SIGNIFICANT CHANGES ASIDE FROM UPDATE FOR 12Z TAF SET.
KEY MESSAGES
1. NEAR-NORMAL TEMPERATURES BUT LOW HUMIDITY THROUGH FRIDAY,
WITH NEAR-ZERO CHANCE OF RAIN.
2. ANOTHER FRONTAL SYSTEM IS EXPECTED TO ARRIVE FROM THE WEST
THIS WEEKEND, BRINGING BACK RAIN CHANCES BUT ALSO BELOW-NORMAL
TEMPERATURES. THE SYSTEM MAY STALL NEAR OUR AREA, AND THUS THIS
PATTERN IS LIKELY TO LINGER INTO EARLY NEXT WEEK.
DISCUSSION
KEY MESSAGE 1: NEAR-NORMAL TEMPERATURES BUT LOW HUMIDITY THROUGH
FRIDAY, WITH NEAR-ZERO CHANCE OF RAIN.
A COLD FRONT WILL CONTINUE PUSHING SOUTH OF THE FORECAST AREA TODAY
UNTIL STALLING NORTH OF THE GULF COAST TONIGHT. A DRY CONTINENTAL
AIRMASS WILL CONTINUE TO BUILD IN BEHIND IT ON BREEZY NORTHWEST
WINDS. LAPSE RATES WILL BE POOR AND THE COLUMN VERY DRY, SO
ASIDE FROM PERHAPS A COUPLE OF BRIEF, STRAY SHOWERS FROM TALLER
CUMULUS THIS AFTERNOON, THE DAY SHOULD BE DEVOID OF ANY DEEP
CONVECTION. TEMPS SHOULD TOP OUT A FEW DEGREES BELOW YESTERDAY'S
MAXES, BACK TO AROUND NORMAL, THOUGH SOME AREAS ALONG/NORTH OF I-40
MAY SEE MAXES SLIGHTLY BELOW NORMAL. LOW-LEVEL CAA WILL CONTINUE
INTO THURSDAY; MIN TEMPS TONIGHT AND MAXES THU ARE EXPECTED TO BE
A LITTLE BELOW NORMAL, AND POPS END UP BASICALLY ZERO. A SLIGHT
REBOUND IN TEMPS IS EXPECTED FRIDAY AS SHORTWAVE RIDGING OCCURS
OVER THE AREA.
DIURNAL MIXING WON'T BE TOO REMARKABLY DEEP, BUT ENOUGH TO TAP
INTO VERY DRY AIR ABOVE 850 MB. THIS APPEARS LIKELY TO BRING RH
DOWN WELL INTO THE 30S PERCENT, AND PER THE NBM 10TH PERCENTILE,
WHICH IS WHAT OFTEN VERIFIES ON MODERATELY MIXED DAYS IN THE
COOL SEASON AND SPRING, A FEW OF THE USUALLY MORE MIXED LOCATIONS
COULD SEE RH DIP BELOW 30 PERCENT. WINDS WILL HOWEVER BE LIGHTER
THURSDAY/FRIDAY COMPARED TO TODAY, AND FUEL MOISTURES ARE NOT
LIKELY TO BE OF CONCERN GIVEN THE WET PATTERN OF LATE.
KEY MESSAGE 2: ANOTHER FRONTAL SYSTEM IS EXPECTED TO ARRIVE FROM THE
WEST THIS WEEKEND, BRINGING BACK RAIN CHANCES BUT ALSO BELOW-NORMAL
TEMPERATURES. THE SYSTEM MAY STALL NEAR OUR AREA, AND THUS THIS
PATTERN IS LIKELY TO LINGER INTO EARLY NEXT WEEK.
THE ANOMALOUSLY DEEP ANTICYCLONE OVER THE DESERT SOUTHWEST WILL
PERSIST THROUGH THE WEEKEND. A WELL DEFINED SHORTWAVE WILL ROUND
THAT FEATURE FRIDAY, PROGRESSING THROUGH THE MS VALLEY AND INTO THE
OHIO VALLEY BY LATE SATURDAY, ACCOMPANIED BY A SURFACE LOW. THIS
WILL REACTIVATE THE STALLED FRONT NEAR THE GULF COAST, IN TURN
LEADING TO INCREASING CLOUD COVER AND PRECIP CHANCES OVER OUR AREA
SATURDAY, BUT ALSO SUPPORTING A WARMING TREND VIA WAA ALOFT. MODELS
CONTINUE TO DIFFER AS TO WHETHER OR WHERE THE SHORTWAVE CUTS
OFF INTO A CLOSED LOW, BUT GENERALLY THAT LOOKS TO OCCUR TO OUR
WEST. WE SHOULD THUS REMAIN UNDER A WARM ADVECTION REGIME SUNDAY
INTO MONDAY, WHEN WE FEATURE LIKELY POP OVER MOST OF THE AREA. A
HYDRO THREAT COULD DEVELOP GIVEN VERY HIGH PWATS AND LIKELY SLOW
STORM MOTION. CONFIDENCE DECREASES BEYOND MONDAY AS DIFFERENCES IN
THE DEPICTION OF THE CUTOFF LOW AFFECT THE POSITION OF THE FRONT,
BUT POPS STILL REMAIN ABOVE CLIMO TUE-WED. CLOUDS AND PRECIP LEAD
TO TEMPS FALLING BACK BELOW NORMAL SUN-TUE.
AVIATION /12Z WEDNESDAY THROUGH SUNDAY/
AT KCLT AND ELSEWHERE: SURFACE FRONT APPEARS TO HAVE BRIEFLY STALLED
EARLY THIS MORNING NEAR THE SC SITES, BUT IT SHOULD PUSH SOUTH IN
THE FIRST FEW HRS OF THE PERIOD. THE EFFECT IS THAT WINDS WILL BE
MORE WESTERLY THERE TO START THE PERIOD, COMPARED TO THE NC SITES
WHICH ARE CLEARLY NORTH OF THE FRONT. NW WINDS WILL PREDOMINATE
OTHERWISE TODAY, VEERING TO N OR NE OVERNIGHT TONIGHT. IFR STRATUS
IS PRESENT IN SOME OF THE NC MOUNTAIN VALLEYS, AND COULD BRIEFLY
EXPAND TO KAVL IN THE FIRST HR OR TWO OF THE PERIOD. ASIDE FROM
THAT, JUST A FEW MOUNTAIN WAVE CIRRUS TODAY ALONG WITH FEW DIURNAL
CU AT VFR LEVEL. VIA MIXING SOME GUSTS OF 15-18 KT ARE LIKELY IN THE
AFTERNOON, POSSIBLY EXCEPTING KAND. GUSTS MAY CONTINUE THROUGH LATE
EVENING AT KAVL AS HIGH PRESSURE CONTINUES TO BUILD IN FROM THE NW,
AND VIA MOUNTAIN GAP EFFECT THESE COULD ALSO BE FELT AT KGSP AND
KGMU. OTHERWISE LIGHT NORTHERLY BREEZES CONTINUING TONIGHT. CAN'T
RULE OUT SOME VALLEY STRATUS/FOG REACHING KAVL AT DAYBREAK THU
BUT CONFIDENCE TOO LOW TO MENTION THIS FAR OUT.
OUTLOOK: DRY AND MOSTLY VFR THROUGH FRIDAY, WITH SHOWER AND
THUNDERSTORM CHANCES AND ASSOCIATED RESTRICTIONS RETURNING THIS
WEEKEND INTO EARLY NEXT WEEK. LOW STRATUS AND/OR FOG WILL BE
POSSIBLE EACH MORNING, MAINLY IN THE MTN VALLEYS.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
JCW
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