


Area Forecast Discussion
Issued by NWS Greer, SC
Issued by NWS Greer, SC
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032 FXUS62 KGSP 291447 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 1047 AM EDT Sun Jun 29 2025 .SYNOPSIS... A typical summer pattern continues into early next week with seasonable temperatures and daily chances for afternoon and early evening thunderstorms. A cold front approaches the area on Tuesday and drier weather may return for the holiday weekend. && .NEAR TERM /THROUGH TONIGHT/... As of 1040 AM EDT Sunday: Morning RAOBs and mesoanalysis shows the air mass will be at least moderately unstable and possibly very unstable once again. Bulk shear is once again very light. PW values are once again very high, nearly 190% of normal. Sfc delta theta-e values are lower for most with highest values over the Upstate and NE GA. DCAPE remains elevated however. Therefore, expect another round of convection initiating over the mountains near noon and spreading into the foothills and I-85 corridor through the afternoon with less coverage south of I-85. Any of the storms could have heavy rainfall with slow movement. Isolated damaging downburst winds are also possible given the DCAPE values. Overall conditions similar to Saturday. Otherwise, the region remains under broad flow and the typical summertime pattern continues. The strong surface high off the eastern coastline amplifies westward, increasing moisture return from the south. Guidance shows an uptick in PWATs through the period into the 1.5-1.75 range, especially east of the mountains. By tonight, dewpoints look to increase into the low 70s, bringing a bit more of the muggy feel. Meanwhile overnight, a few areas could see some patchy low-level stratus or fog near daybreak, mostly confined to the mountain valleys. If any should develop, expect it to clear after daybreak. As for Sunday, the area remains in general thunder from the Storm Prediction Center as another round of afternoon pop- up convection ensues. A bit of a surface shortwave is expected to meander through the southeast, which could provide additional lift to the more typical diurnally driven storms. However, the steering flow is nonexistent as winds aloft are extremely weak to calm. Once again an inverted-V on modeled soundings show an environment capable of rapid evaporative cooling. This is apparent with dCAPE values nearing 1000 J/kg, increasing the chances for strong winds out of developing downbursts. Cannot rule out a severe storm, but it would mainly be for winds. Most of the storms should weaken into Sunday evening as peak heating ceases. Depending on what areas can get rain, there is a chance for some more low-level stratus and patchy fog again tonight, especially in the mountain valleys. As far as temperatures, low 90s east of the mountains and overnight lows dipping into the low 70s. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... As of 300 am Sunday: A weakness in the subtropical ridge covering the Southeast will evolve into more of a trough during the short term, as heights fall in response to a series of short wave troughs traversing the northeast Conus and southeast Canada. With southerly flow around a Bermuda high supplying plenty of moisture...precipitable water values of around 1.75"...and strong insolation allowing the atmosphere to destabilize to the tune of 2000-3000 J/kg each day...conditions will remain favorable for diurnal convective development...with likely PoPs warranted across the mountains and 40-50% chances elsewhere Monday afternoon. Convective chances will be further enhanced Tuesday, as low-level boundary moves into the area in association with height falls, and 70-90 PoPs are warranted across the entire CWA during the afternoon and evening. Similar to the last couple of days...a few pulse severe storms will be possible on Monday, with locally heavy/isolated excessive rainfall also possible in light of continued slow cell movement. Deep layer shear is forecast to increase to around 20 kts on Tuesday, so some degree of modest organization/clustering along outflows will become possible, which combined with overall higher coverage will yield an uptick in the severe storm potential. Although cell movement will increase Tuesday, high moisture content will continue to produce some threat for isolated excessive rainfall. Temperatures will remain slightly above normal and min temps several degrees warmer than climo through the period. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... As of 315 am Sunday: Upper trough axis and associated low level boundary will gradually become established E=>S of the forecast area early in the extended...allowing lower theta-E/drier air to gradually filter into the region during the latter half of the week. Sufficient moisture and instability should linger on Wednesday to support scattered convection...especially across the southern zones and portions of the Blue Ridge. With drier/less unstable air settling over the area, the remainder of the week is expected to see below-normal coverage of diurnal convection...with general 20-30 PoPs advertised over the mountains...and 10-20% chances elsewhere each afternoon Thu through Sat. Temps are mostly forecast at 1-2 degrees above climo through the period. && .AVIATION /15Z SUNDAY THROUGH THURSDAY/... At KCLT and elsewhere: VFR conditions prevail through the TAF period at most sites. High pressure off to the west of the area allows for more southerly winds this afternoon, but still remain light. Another chance for scattered showers and TSRA, possible anywhere especially in the mountains. Chances are higher for the mountains so will add a TEMPO at KAVL and HKY, with PROB30s elsewhere. Once showers and thunderstorms clear up, another calm night ahead. Depending on whether or not the mountain sites can receive any rain, will greatly impact the BR/FG chances before the end of the TAF period. Outlook: Daily chances for afternoon and evening showers and thunderstorms into next week. Fog and/or low stratus possible each morning in the usual mountain valleys as well as near lakes and rivers. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...CP NEAR TERM...CP/RWH SHORT TERM...JDL LONG TERM...JDL AVIATION...CP/RWH