Area Forecast Discussion
Issued by NWS Greer, SC
Issued by NWS Greer, SC
729 FXUS62 KGSP 210005 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 805 PM EDT Mon Jul 20 2026 .WHAT HAS CHANGED... Shower and thunderstorm chances have trended lower on Tuesday across most of our forecast area. Chances have trended higher towards the end of the week and into the weekend. && .KEY MESSAGES... 1. Elevated heat index values continue through Wednesday. Cooler temperatures later in the week should provide some relief from the heat. 2. A few showers/storms will continue this evening across the mountains and foothills. Less convective coverage is expected on Tuesday, however a few severe storms remain possible. A weak cold front brings increased coverage and the potential for more severe weather on Wednesday. && .DISCUSSION... Key message 1: Elevated heat index values continue through Wednesday. Cooler temperatures later in the week should provide some relief from the heat. High temperatures are again expected in the low to mid 90s outside of the mountains Tuesday. Dewpoints should mix out enough to keep heat index values below 105 degrees for most locations. Nonetheless, we can`t rule out a few brief values of 105 along and south of the I-85 corridor each day. Temperatures are still expected to fall a few degrees on Wednesday, however dewpts remain elevated. This keeps heat index values elevated along and south of the I-85 corridor. An airmass change is expected behind a cold front on Thursday and Friday. Below normal high temperatures are fcst Thursday, Friday, and into the weekend providing a welcome break from the heat and humidity. Until then, stay hydrated, take frequent breaks in air-conditioned or shaded areas, and never leave children or pets unattended in vehicles. Key message 2: A few showers/storms will continue this evening across the mountains and foothills. Less convective coverage is expected on Tuesday, however a few severe storms remain possible. A weak cold front brings increased coverage and the potential for more severe weather on Wednesday. A weak convergence zone, a remnant of the front which settled to NC last night, persists over the region which seems to be helping maintain clusters of storms over the mountains as of 8 PM Mon. This activity should gradually diminish in intensity, though with the convergence and also numerous outflow boundaries lingering, can`t rule out new isolated development through midnight or so before the boundaries wash out. Convective coverage for Tuesday has been trending lower across most of our CWA. Chances remain high across the northern NC mtns and foothills, where what`s left of the sfc front lingers, but shower/thunderstorm chances taper off substantially south of there. Nonetheless, the potential for a few severe storms with damaging winds continues on Tuesday. Coverage is expected to increase again on Wed as an upper trof amplifies over the eastern CONUS and moves yet another cold front into our area. Severe storm potential may also increase again on Wed with the better forcing, moisture convergence, and bulk shear to go along with the unstable airmass. More typical diurnal convective chances return for the end of the week. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... At KCLT and elsewhere: Clusters of SHRA/TSRA over the mountains warranted including TEMPO TSRA at KAVL this evening. Elsewhere, a subtle convergence axis was evident in satellite imagery south of the SC terminals which was drifting slowly northward. An isolated storm could form along that boundary in the couple of hours after sunset. Chance of direct TS impacts appear small enough at KCLT and the SC sites only to mention VCSH. KHKY is behind outflow from another cluster and is likely done for the night. Aside from convective debris AOA FL100 skies will be mostly clear much of the night and winds generally trending light SW. Mountain valley fog/stratus appear likely, and with KAVL having a couple of brief showers in the day/evening a TEMPO for nocturnal IFR also was included. VFR expected elsewhere. Coverage of SHRA/TSRA slightly more sparse Tuesday and no mention yet made for the afternoon, but diurnal cu will develop by late morning. Gusty SW`ly winds. Outlook: SHRA/TSRA coverage is expected to increase again on Wednesday and Thursday as a front settles southward through the area, with chances then decreasing for Friday. Low stratus and/or fog will be possible each morning, mainly in the mtn valleys. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$