Area Forecast Discussion
Issued by NWS Greer, SC
Issued by NWS Greer, SC
349 FXUS62 KGSP 141757 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 157 PM EDT Mon Jul 14 2025 .SYNOPSIS... A typically active mid-summer week is ahead as daily thunderstorm chances continue. A few storms could produce damaging wind gusts and localized flash flooding. Daily high temperatures will trend back to around the normal mid-July mugginess Tuesday through Thursday. && .NEAR TERM /THROUGH TUESDAY/... As of 1245 PM EDT Monday: Fairly quiet still as we work our way into the afternoon, with little in the way of deep sustained convection thus far. The environment isn`t quite as robust as the previous few, with sfc-based CAPE only in the 1500-2500 K/kg range in spite of temps having already pushed into the 90s outside the mtns, probably because of more tendency to mix down the dewpoint a bit earlier compared to yesterday. The environment over the mtns never really gets all that unstable through the afternoon, according to the model guidance, which is probably why the CAMs never really show much coverage. The better chances, albeit maybe only 30-40pct at best, might be from the Escarpment eastward later this afternoon. Won`t rule out a few wet microburst pulse severe storms, mainly over the eastern half of the fcst area, so we won`t argue with the Marginal Risk in the Day 1 Outlook. The profiles show more moisture than yesterday, so there`s an uptick in heavy rain potential, but the better chances of flooding rain are definitely off to our east and northeast. Most likely, the convection will have a diurnal tendency and will weaken after sunset, but it is worth mentioning the HRRR that appears to keep some sort of weak boundary across the area east of the mtns that is a focus for convection through the late evening and early morning hours. The fcst hasn`t been changed much in that regard, and still holds onto a swath of precip chances mainly over the western Piedmont and nrn Upstate past midnight. Confidence is fairly low because we are stuck in weak flow aloft in between the ridge to the south and the short wave that has lifted out to the northeast. Because of the deep warm cloud depth, high precipitable water, and weak flow late tonight, there`s a sneaky flash flood potential over the western Piedmont late late tonight if we can get convection to develop, which the CAMs are not altogether excited about. Otherwise, there`s more of an indication of mtn valley fog and low stratus compared to the weekend. Low temps will be seasonally warm. For Tuesday, the guidance shows better coverage of deep convection that gets an earlier start. We will be under an expanding flat upper anticyclone, so the trigger will be differential heating over the higher terrain, which all the CAMs are showing. Storms would eventually work their way off the Escarpment and down across the Piedmont along cold pools and outflow boundaries thru the afternoon. Profiles are not especially favorable for severe storms. High temps will be a few degrees cooler because of the early start, more clouds, and more numerous storms. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... As of 1215 PM Monday: The mean pattern atop the region changes little through the period, continued southerly flow around Bermuda high pressure, with the wwd extent of the upper ridge axis lingering over the area. The synoptic scale feature of interest is the wwd moving inverted trough evolving into the gulf on Wednesday. There exists the ongoing probabiliy of tapping into tropical moisture as richer PWATs are progged to blossom nwd within reinforced southerly llvl flow. The trend of becoming slight less hot will continue but with sfc dwpts nudging higher it will still feel quite muggy. With the deep layered ridge axis poking further wwd into the cwfa on Thursday, the llvl flow will continue to veer to a more SW direction, perhaps resulting in dirunally enhanced deep convective chances trending back toward the mid-July climo, given the richer than typical moisture, storms will probably become numerous again. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... As of 115 PM Monday: Expecting to heat back above to above normal temperatures through the period with Piedmont solid middle 90s possible by Sunday. Also over the weekend, there is the ongoing chance of experiencing apparent temperatures in the lower 100s each afternoon. The upper ridge axis centered offshore to start off the period translates wwd to atop the SE CONUS through Sunday with the southern edge of the westerlies and perhaps a llvl baroclinic zone encroaching our northern tier. Despite the upper ridge positioning, daily thunderstorm chances will remain above climo with an ongoing risk localized flash flooding with in the lingering weak flow regime. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... At KCLT and elsewhere: VFR at all terminals outside of widely scattered thunderstorms through late tonight, with a light/variable wind. Will keep the PROB30 at all terminals for the afternoon/evening, after which it should be quiet. Moisture is a bit higher tonight, so fog/low stratus is a better bet at KAVL/KHKY, and possibly even at KCLT. For Tuesday, the model guidance suggests a more convectively active day with an earlier start, so just about everyone could get a PROB30 before the end of the forecast period. Wind will come around to light S to SE. 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