Area Forecast Discussion
Issued by NWS Greer, SC
Issued by NWS Greer, SC
980 FXUS62 KGSP 201900 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 300 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. Another round of scattered showers and thunderstorms this afternoon and evening, with a few severe storms possible. 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 remain steady in the low to mid 90s outside of the mountains today and 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: Another round of scattered showers and thunderstorms this afternoon and evening, with a few severe storms possible. 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 frontal boundary stalls over NC today, helping keep better shower/thunderstorm chances across the state. Most of the latest CAM guidance keeps NE GA and the SC Upstate mostly dry, with notably better coverage over the NC mountains and foothills. This appears reasonable given the greater instability and better low-level con- vergence over western NC. Shear is limited today but the airmass over NC has plenty of CAPE, high PW values, and steep low-level lapse rates. This maintains a severe storm threat with damaging winds being the main hazard. 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 /18Z MONDAY THROUGH SATURDAY/... At KCLT and elsewhere: Sct showers and a few thunderstorms have initiated over western NC during the past hour or so. With a lingering frontal boundary draped across NC, I expect most of the activity to remain over western NC with minimal activity over the SC Upstate and NE GA. As such, I have TEMPOs for TSRA and gusty winds at KAVL and KHKY from roughly 18 to 22z with VCTS after that for any lingering convection in their vicinity. I have a PROB30 for TSRA at KCLT this aftn/evening with VCSH for any lingering showers after that. I did not include any mention of convection at the Upstate terminals as coverage should be considerably less over that area today. Otherwise, there`s a good chance of mtn valley fog/low stratus again overnight and a decent chance it could reach KAVL again. So, I have prevailing MVFR conditions beginning around 09z with a TEMPO for IFR from 09 to 13z. Winds should remain S to SW this aftn/evening becoming lighter tonight. They will pick back up from the S/SW tomorrow morning with speeds increasing to 6 to 12 kts with low-end gusts expected at most sites. At KAVL, winds will go light and VRB this evening and then calm overnight. They will pick up from the S/SW later tomorrow morning. Outlook: SHRA/TSRA may return again Tuesday, though activity is likely to remain over the NC mtns and foothills. Coverage is ex- pected to increase again on Wednesday and Thursday then decrease on 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. && $$ JPT