


Area Forecast Discussion
Issued by NWS Greer, SC
Issued by NWS Greer, SC
842 FXUS62 KGSP 131738 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 138 PM EDT Sun Jul 13 2025 .SYNOPSIS... A typically active mid-summer week is ahead as daily thunderstorm chances continue. A few storms could produce damaging wind gusts, particularly Monday. Daily high temperatures will be several degrees above normal at the beginning of the week but trend back to around normal Tuesday through Thursday. && .NEAR TERM /THROUGH MONDAY/... As of 1245 PM EDT Sunday: The fcst appears to be on track early this afternoon. Satellite imagery shows evidence of the stronger mid/upper ridge overhead. Convective initiation has occurred over the mountains, mainly over the high elevations of the Balsams, but also over the Smokies and Nantahala mountains. This should also take place elsewhere over the higher terrain into the middle part of the afternoon. Meanwhile...a lingering patch of mid-level cloudiness was delaying the warmup and convection over the I-77 corridor. The morning guidance continues to support the idea that coverage of storms will be less than the last few days and the precip probs continue to reflect that thinking. It`s not for lack of buoyancy, which will range from 2000 to 3000 J/kg of sfc-based CAPE, but for lack of triggers and more mid-level dry air to overcome. That dry air layer will provide for higher dCAPE than the previous few days, greater than 800 J/kg across the whole area, so in spite of the lack of a marginal risk on the Day 1 Outlook, any storms that manage to really get going will have more of a wet microburst risk than yesterday. Our flash flood threat is relatively less, however. No need to give up on the high temp forecast just yet. Dewpoint should mix out just enough to keep the apparent temp below Heat Advisory criteria. Any storms that manage to persist into the early evening should diminish an hour or so after sunset. After that, yet another muggy night with temps above normal, clearing sky, and a chance of mtn valley fog in the pre-dawn hours. For Monday, the upper ridge over the Southeast should flatten and expand as the weak upper wave to our NW lifts out and deamplifies quickly as it passes well to our north through the afternoon. This suggests a continuance of what essentially amounts to a slightly higher than climo precip prob across most of the area. The mtns are the exception, where precip probs will go into the likely range, mostly because of the HRRR suggestion of some better coverage and organization along a possible outflow boundary, from previous convection, that reaches the mtns during afternoon heating. Profiles look tall and skinny and mid-level dry air is not as pronounced on fcst soundings, so perhaps our severe threat will trend back down. As for temps...it looks like another hot one...but with dewpoints mixing out enough again to keep the apparent temp below Advisory criteria in the afternoon. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... As of 1155 AM Sunday: The upper ridge axis is progged remain atop the cwfa through the period while continued southerly flow around Bermuda high pressure advects higher PWAT values into the region, which seem to be tropical in nature originating closer to the wwd moving inverted trough. Despite the upper ridge positioning, given broad southerly llvl convergence and richer moisture, diurnally enhanced showers and thunderstorms are expected to become numerous each day with locally excessive rainfall on ongoing threat. We will be stepping away Monday`s Piedmont maximum middle 90s progging values closer to climo Tuesday and Wednesday, but sfc dwpts will wind up being higher with less chances of downward mixing. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... As of 1230 PM Sunday: The cwfa still looks to be within the periphery of the circulation around Bermuda high pressure to start off the period with the deterministic GFS/ECMWF both rebuilding the center of strong upper anticyclone back atop the region for Friday. So, daily maximums will creep back upward to above climo by Friday. Potentially widespread deep convection on Thursday may trend back to climo pop on Friday if ridge in fact does build as progged. The medium range models are hinting that upper ridge central will shift wwd over next weekend, but at this point, sensible wx will be typical for mid-July for Saturday and Sunday. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... At KCLT and elsewhere: VFR at all terminals thru evening away from thunderstorms. Coverage of convection should be less than the past few days, so TAFs are limited to PROB30s and will be amended based on radar trends later this afternoon. Wind will be light NW or variable. After sunset, only convective cloud debris will remain. Low confidence in low stratus/fog at KAVL overnight based on recent model performance, but will include at least a temporary restriction for now. For Monday, another afternoon storm chance similar to today, so only KCLT will get the PROB30 right now because of the 30 hr period. Wind will be light/variable thanks to weak high pressure. Outlook: Typical summertime weather is expected into early next week, with scattered to numerous thunderstorms mainly in the afternoon/evening and fog and/or low stratus possible each morning. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...CSH NEAR TERM...PM SHORT TERM...CSH LONG TERM...CSH AVIATION...PM