Area Forecast Discussion
Issued by NWS Greer, SC
Issued by NWS Greer, SC
333 FXUS62 KGSP 140522 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 122 AM EDT Thu Aug 14 2025 .SYNOPSIS... Abundant moisture over the Southeast will keep scattered to numerous showers with mainly afternoon thunderstorms through Friday. As a somewhat shallow upper ridge builds over our region during the weekend and early next week, temperatures warm to near normal. Afternoon thunderstorms become more isolated to scattered from Sunday into early next week. && .NEAR TERM /THROUGH TONIGHT/... Key Messages: 1) Multiple rounds of showers and storms through Thursday, producing an isolated flash flood threat. 2) Temperatures warm into the low 90s in some locations east of the mountains. As of 120 AM EDT Thursday: Ongoing showers and thunderstorms are currently moving across the mountains. Taking a look at the synoptic setup, it`s similar to what the CWA has been stuck under for the last few days. A ridge starts to amplify over the central CONUS and high pressure over the Atlantic churns and advects moisture into the area. Guidance also shows a decent shortwave coming through overnight, but is keeping it to the southern portion of the CWA. This could enhance rain chances overnight should anything fire off the outflow boundary. Current PMM in the SHREF shows some minimal amounts of rain totals around 1 inch. But again, any areas that receive training storms have an increased risk for flash flooding, especially over highly saturated soils. CAM guidance is unreliable at this point. It`s humid. There are plenty of ingredients to enhance rainfall. It`s going to rain on and off. Later today, the same story. Pop-up showers likely with higher PoPs (50-75%) CWA wide. Current guidance has around 500-1000 J/kg of sbCAPE forming, but this will be dependent on how much of a break in the clouds occur during the afternoon. For this, scattered showers and thunderstorms this afternoon, but nothing severe anticipated at this time. Given the abundant moisture in the area, there could be patchy fog at daybreak, especially in areas that receive rainfall overnight. Temperatures are more typical for August and a few areas in the southern zones could reach the low 90s. Add the high humidity to those hotter temps and heat indices approach the upper 90s in the far southern counties of SC and NE Georgia. The good news, values will not even get close to any Heat Advisory criteria. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... As of 100 AM Thursday: A subtropical anticyclone/upper ridge axis starts out over the area at the beginning of the period but retrogrades into the MS River valley through the period. This brings a NW flow over the area with weak short waves dropping through the flow and across the area. A drier air mass settles into the area from the north through the period with PW values returning to more normal levels. This also brings a return to a more normal diurnal convective weather pattern, with better coverage favoring the mountains each day. This also brings an increase in the potential for strong to possibly severe storms. Brief, heavy rainfall is possible with any storm keeping an isolated flood threat in place. Highs will be near to slightly above normal each day. Dew points remain high enough on Friday for a smattering of around 100 heat index values along and south of the I-85 corridor. Dew point and heat index values will be lower on Saturday. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... As of 120 AM Thursday: The axis of the upper ridge reasserts itself over the area through Tuesday. A weak upper trough moving out of the Great Lakes into the East Coast will be strong enough to knock down the ridge and move into our area. With the ridge building, the better diurnal convective chances retreat to mainly the mountains Sunday and Monday, then slowly increase back across the area Tuesday and Wednesday as the trough moves in. Temps will remain near to slightly above normal through Tuesday then drop to slightly below normal Wednesday. Right now, guidance shows the Wednesday trough helping recurve Erin and keeping it off shore of the Carolinas. As usual, keep an eye on the latest tropical forecast in the event of any forecast changes. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... At KCLT and elsewhere: Ongoing showers and TSRA over a number of terminals is triggering brief restrictions. TSRA and RA are expected to continue during the overnight hours, especially at the mountain terminals. Currently, the line of rain is grazing KCLT, but will prevail -RA at this time. There could be some IFR/LIFR before sunrise at areas where the rain dissipates. The confidence is higher at KAVL, hence a TEMPO for vsby from 10z-13z. As winds slowly come back up during the early morning hours, conditions should improve. Another day of pop-up showers and TSRA possible in the afternoon hours. So, yet again, PROB30s for all terminals. Winds throughout the TAF period become VRB to calm overnight and then prevail SW at terminals outside the mountains. KAVL and KHKY remain more N/NW but can become VRB with storms. Outlook: Showers and thunderstorms with associated restrictions are expected across the area each day this week. Morning fog/low stratus is also possible, especially across the mountain valleys. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...RWH NEAR TERM...CP SHORT TERM...RWH LONG TERM...RWH AVIATION...CP