Flat Rock

• This Afternoon

  78°high

  Mostly Sunny

  Mostly sunny, with a high near 78. East southeast wind around 5 mph.

  Wind ESE 5 mph · 1% chance of precipitation

• Tonight

  62°low

  Mostly Cloudy then Patchy Fog

  Patchy fog after 4am. Mostly cloudy, with a low around 62. Northeast wind 0 to 5 mph.

  Wind NE 0 to 5 mph · 1% chance of precipitation

• Wednesday

  83°high

  Patchy Fog then Mostly Sunny

  Patchy fog before 10am. Mostly sunny, with a high near 83. North northeast wind 0 to 6 mph.

  Wind NNE 0 to 6 mph · 2% chance of precipitation

• Wednesday Night

  62°low

  Mostly Clear

  Mostly clear, with a low around 62. East wind 0 to 5 mph.

  Wind E 0 to 5 mph · 1% chance of precipitation

• Thursday

  86°high

  Mostly Sunny then Slight Chance Showers And Thunderstorms

  A slight chance of showers and thunderstorms after 5pm. Mostly sunny, with a high near 86. North northeast wind around 3 mph. Chance of precipitation is 20%.

  Wind NNE 3 mph · 17% chance of precipitation

• Thursday Night

  65°low

  Slight Chance Showers And Thunderstorms then Mostly Clear

  A slight chance of showers and thunderstorms before 7pm. Mostly clear, with a low around 65. Chance of precipitation is 20%.

  Wind WNW 1 to 5 mph · 15% chance of precipitation

• Friday

  86°high

  Mostly Sunny then Chance Showers And Thunderstorms

  A chance of showers and thunderstorms after 2pm. Mostly sunny, with a high near 86. Chance of precipitation is 50%.

  Wind N 6 mph · 52% chance of precipitation

• Friday Night

  65°low

  Chance Showers And Thunderstorms

  A chance of showers and thunderstorms before 2am. Mostly cloudy, with a low around 65. Chance of precipitation is 50%.

  Wind NNW 3 mph · 47% chance of precipitation

• Saturday

  79°high

  Chance Showers And Thunderstorms

  A chance of showers and thunderstorms after 8am. Partly sunny, with a high near 79. Chance of precipitation is 50%.

  Wind ENE 2 to 6 mph · 50% chance of precipitation

• Saturday Night

  63°low

  Chance Showers And Thunderstorms

  A chance of showers and thunderstorms before 2am. Mostly cloudy, with a low around 63. Chance of precipitation is 50%.

  Wind SSE 3 mph · 50% chance of precipitation

• Sunday

  82°high

  Partly Sunny then Chance Showers And Thunderstorms

  A chance of showers and thunderstorms after 2pm. Partly sunny, with a high near 82. Chance of precipitation is 50%.

  Wind SW 3 mph · 51% chance of precipitation

• Sunday Night

  63°low

  Chance Showers And Thunderstorms

  A chance of showers and thunderstorms before 2am. Mostly cloudy, with a low around 63. Chance of precipitation is 50%.

  Wind NNW 3 mph · 51% chance of precipitation

• Monday

  80°high

  Showers And Thunderstorms Likely

  A slight chance of rain showers between 8am and 2pm, then showers and thunderstorms likely. Partly sunny, with a high near 80. Chance of precipitation is 60%.

  Wind SSW 1 to 5 mph · 62% chance of precipitation

• Monday Night

  63°low

  Showers And Thunderstorms Likely

  Showers and thunderstorms likely before 2am. Mostly cloudy, with a low around 63.

  Wind NNE 3 mph · 62% chance of precipitation

The reasoning behind the forecast, in the forecaster’s own words. In this region the elevation detail that never reaches a point forecast usually shows up here.

000
FXUS62 KGSP 151821
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
221 PM EDT Tue Sep 15 2026

.WHAT HAS CHANGED...
No significant changes were made to the forecast.

The aviation discussion was updated for the 18z TAFs.

&&

.KEY MESSAGES...
1. Above normal temperatures with increasing shower and
thunderstorm chances through the weekend. A cold front on Tuesday
brings a better chance of widespread precipitation and near
normal temperatures.

&&

.DISCUSSION...
Key message 1: Above normal temperatures with increasing shower and 
thunderstorm chances through the weekend. A cold front on Tuesday 
brings a better chance of widespread precipitation and near normal 
temperatures. 

Clouds scatter out with an isolated shower possible this afternoon 
with highs near or a little above normal. Low clouds may return 
tonight but mountain valley fog/stratus is more likely. 

An upper anticyclone over the mid MS Valley remains in place through 
Friday with a ridge extending from it east over our area. At the 
surface, a damming high lookalike over the area Wednesday weakens as 
a back door cold front approaches from the north. A dry forecast is 
expected Wednesday with diurnal convective chances slowly increasing, 
mainly across the mountains, Thursday and Friday. Unfortunately, 
highs rise back into the low to mid 90s outside of the mountains, 
around 90 in the warmer mountain valleys, by Friday. 

The anticyclone weakens and retrogrades over the weekend as a series 
of shortwaves cross the Mid-Atlantic and an upper low moves west 
across Florida. The shortwaves help push the back door cold front 
into the area Saturday which dissipates on Sunday. This keeps shower 
and thunderstorm chances across the area with highs dropping back 
into the upper 80s to around 90. 

Another cold front moves in from the northwest Monday and east of 
the area Tuesday. This has the potential for more widespread shower 
and thunderstorm chances with highs dropping to near normal for 
Tuesday.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
At KCLT and elsewhere: MVFR stratocu is slowly scattering 
out/lifting and should be VFR all areas by 20Z with mostly clear 
skies near or shortly after sunset. An isolated shower or storm is 
possible over the mountains, but chance too low for the KAVL TAF. 
Guidance has backed off on low clouds overnight outside of the 
mountains. That said, there will be some low level moisture and 
light southeasterly flow, so this will need to be watched for later 
TAFs. Mountain valley fog and low stratus is more likely with the 
usual question of whether it reaches KAVL. Have just gone with SCT 
low clouds for now. Some VFR CU expected for the afternoon. ENE 
wind, SE at KAVL, this afternoon becomes light and variable by 
evening. Light ENE wind, NNW at KAVL, develops on Wednesday. 

Outlook: Convective chances and associated restrictions increase 
into the weekend. Mountain valley fog and low stratus is possible 
each morning.

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.

&&

$$

RWH