975
FXUS62 KGSP 131753
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
153 PM EDT WED MAY 13 2026
WHAT HAS CHANGED
NO SIGNIFICANT CHANGES TO THE FORECAST WITH THIS PACKAGE.
KEY MESSAGES
1. A COLD FRONT WILL BRING SPOTTY SHOWERS, AND POSSIBLY A
THUNDERSTORM, THIS AFTERNOON AND EVENING. BRIEF PERIOD OF COOLER
WEATHER THROUGH THURSDAY AND THURSDAY NIGHT.
2. DRY WEATHER RETURNS TO END THE WEEK, WITH TEMPERATURES WARMING
AND HUMIDITY GRADUALLY INCREASING OVER THE WEEKEND AND EARLY
NEXT WEEK.
DISCUSSION
KEY MESSAGE 1: A COLD FRONT WILL BRING SPOTTY SHOWERS, AND POSSIBLY
A THUNDERSTORM, THIS AFTERNOON AND EVENING. BRIEF PERIOD OF COOLER
WEATHER THROUGH THURSDAY AND THURSDAY NIGHT.
A COLD FRONT IS PROGGED TO MOVE ACROSS THE CWFA LATER THIS
AFTERNOON AND EVENING AS AN UPPER TROUGH SLIDES OVER THE GREAT
LAKES REGION AND NORTHEAST. FORCING FOR ASCENT IS MODEST TO GO
ALONG WITH A MOISTURE STARVED AIRMASS. CAMS CONTINUE TO SHOW A
LINE OF SHOWERS AND THUNDERSTORMS DEVELOPING OVER THE IMMEDIATE TN
BEFORE GRADUALLY WEAKENING AS IT PUSHES FURTHER EAST, ESPECIALLY
OUTSIDE OF THE MOUNTAINS. A QUICK SHOWER SHOT CANT BE RULED OUT
EAST OF THE MOUNTAINS, BUT LATEST TRENDS HAVE SLIGHTLY LOWERED
IN OVERALL COVERAGE, WITH THE BEST CHANCES BEING IN THE NORTHERN
UPSTATE AND NC PIEDMONT DURING THE EVENING TIMEFRAME. OTHERWISE,
THE FRONT WILL MAKE A CLEAN PASSAGE OVERNIGHT TONIGHT AS CAA FILLS
IN BEHIND IT WITH WEAK HIGH PRESSURE SPILLING OVER THE REGION
TONIGHT INTO THURSDAY.
UNDER CONFLUENT UPPER FLOW BETWEEN THE NORTHEAST CONUS CUTOFF
LOW AND A RIDGE MOVING INTO THE MISSISSIPPI VALLEY, DRY SURFACE
HIGH PRESSURE WILL SHIFT ACROSS THE SOUTHERN APPALACHIANS THROUGH
THURSDAY AND FRIDAY BEFORE CENTERING EAST OF THE CWA. MAX TEMPS
LOOK TO TREND COOLER ACROSS THE AREA THURSDAY, AS MUCH AS 10
DEGREES COOLER ACROSS THE MOUNTAINS AND NORTHERN FOOTHILLS,
BUT WITH DOWNSLOPE NW WINDS OFFSETTING THE CAA ACROSS MOST OTHER
AREAS FOR A LESS NOTICEABLE DROP. MODEST WIND GUSTS APPEAR LIKELY
THURSDAY GIVEN THE GRADIENT FLOW ACROSS THE HIGHER TERRAIN AND GOOD
MIXING IN THE DOWNSLOPE AREAS. HOWEVER, THE MODELS THAT EXPLICITLY
FORECAST GUSTS, SUCH AS THE ECMWF AND HRRR, HAVE BOTH TRENDED LOWER
IN THEIR DEPICTIONS FOR THURSDAY. RH STILL IS EXPECTED TO DIP TO
THE 25-30% RANGE IN THE PIEDMONT. THURSDAY NIGHT, SKIES BECOME
VIRTUALLY CLEAR AND WINDS RELAX AS THE HIGH CENTERS OVER THE CWA,
THOUGH NOT NECESSARILY QUICKLY ENOUGH TO ENSURE PRIME RADIATIONAL
COOLING CONDITIONS. SHELTERED AREAS SUCH AS SMALL MOUNTAIN/RIVER
VALLEYS WOULD BE THE EXCEPTION. MINS THU NIGHT INTO FRI MORNING
WILL BE AROUND 10 BELOW NORMAL FOR THE PIEDMONT, 10-15 IN THE
MOUNTAINS. A FEW ISOLATED MOUNTAIN SPOTS COULD DIP TO THE MID 30S
AND LIGHT FROST COULD RESULT THERE.
KEY MESSAGE 2: DRY WEATHER RETURNS TO END THE WEEK, WITH TEMPERATURES
WARMING AND HUMIDITY GRADUALLY INCREASING OVER THE WEEKEND AND
EARLY NEXT WEEK.
LIGHT SOUTHWEST FLOW IS RESTORED OVER THE REGION FRIDAY WITH THE
HIGH CENTERING OFFSHORE AND HEIGHTS RISING ALOFT. TEMPS MODERATE AND
TREND A FEW DEGREES WARMER, ESPECIALLY IN MOUNTAIN VALLEYS PRONE TO
DOWNSLOPING IN SW FLOW; DESPITE SOME MOISTURE RETURN LOW RH NEAR 30%
IS FORECAST ONCE AGAIN, WITH STILL LOWER RH IN THOSE SAME MOUNTAIN
VALLEYS. UPPER PATTERN TURNS QUASI-ZONAL OVER THE SOUTHEAST
SATURDAY, WITH AIRMASS CONTINUING TO MODIFY; UPPER RIDGE BUILDS OVER
THE SOUTHEAST COAST FOR SUNDAY LEADING TO STILL WARMER TEMPERATURES.
HUMIDITY WON'T BE QUITE AS LOW, BUT STILL SOMEWHAT BELOW NORMAL FOR
LATE MAY. TEMPS HOLD FAIRLY STEADY MONDAY AND TUESDAY BUT HUMIDITY
WILL TREND HIGHER.
MODELS AND ENSEMBLE MEMBERS STILL GENERALLY DEPICT A FRONT STALLING
IN THE OHIO VALLEY SATURDAY, BUT HAVE NOT COME INTO ANY BETTER
AGREEMENT AS FAR AS WHETHER ANY CONVECTION DEVELOPING ALONG IT WILL
PROPAGATE INTO OUR CWA FROM THE WEST, SO WE RETAIN ONLY 10-20% POPS
SATURDAY AND SUNDAY OVER THE NC MOUNTAINS. WEAK DIURNAL INSTABILITY
MAY DEVELOP SUNDAY AND MONDAY, BUT LACKING MUCH OF A TRIGGER PRECIP
CHANCES REMAIN LOW. A COLD FRONT WILL APPROACH THE AREA TUESDAY,
AND IN THE PREFRONTAL ENVIRONMENT POPS INCREASE TO 20-30% OVER
THE MOUNTAINS, BUT THE LATEST ENSEMBLES INDICATE THE BETTER CHANCE
WOULD BE WEDNESDAY. PROBABLY NOT LOOKING AT ANY APPRECIABLE RAINFALL
UNTIL AFTER THE END OF THE CURRENT FORECAST PERIOD. WITH THE SETUP
APPEARING TO FAVOR NONSEVERE PULSE STORMS TUESDAY, LOCALIZED HEAVY
RAINFALL COULD OCCUR BUT NOT PROVIDING REAL DROUGHT RELIEF.
AVIATION /18Z WEDNESDAY THROUGH MONDAY/
AT KCLT AND ELSEWHERE: VFR THROUGH MUCH OF THE FORECAST PERIOD. A
COLD FRONT WILL MOVE IN THIS EVENING AND DEVELOP A LINE OF SHOWERS,
WITH SOME EMBEDDED THUNDER POSSIBLE. THE BEST CHANCES ARE AT THE
NORTH CAROLINA TERMINALS, SO KEPT THE PROB30 MENTION FOR SHRA AND
ASSOCIATED RESTRICTIONS THIS AFTERNOON/EVENING. SOME MID AND UPPER
LEVEL CLOUDS WILL MOVE ACROSS THE AREA. CAN'T RULE OUT LOW CIGS
IN THE VICINITY OF A HEAVIER SHOWER OR STORM, BUT CIGS EXPECTED
TO REMAIN AT VFR. SOUTH TO SOUTHWEST WINDS AHEAD OF THE FRONT,
WILL TURN NORTHWESTERLY BEHIND THE FRONT LATE THIS EVENING INTO
THE OVERNIGHT HOURS. CAN'T RULE OUT SOME LOW-END GUSTS DURING THE
FRONT'S PASSAGE, BUT BETTER CHANCES OF GUSTY WINDS ARE EXPECTED
LATER THURSDAY MORNING INTO THE AFTERNOON. INCLUDED A LOW-END GUST
MENTION AT ALL SITES AND BUMPED UP GUSTS AT KAVL WHERE GUSTS UP
TO 25-30 KTS CAN'T BE RULED OUT.
OUTLOOK: VFR AND QUIET WEATHER IS EXPECTED FOR THE REST OF THE
WEEK. MOISTURE BEGINS TO INCREASE OUT OF THE SOUTH OVER THE WEEKEND,
BUT CONFIDENCE ON A RETURN TO ANY DIURNAL CONVECTIVE RAIN CHANCES
REMAINS LOW.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
CAC/JCW
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