textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

Updated the aviation discussion for the 00Z TAF issuance.

KEY MESSAGES

1. Hot and muggy conditions persist through the end of the week, with slightly cooler temps behind a cold front this weekend. 2. Showers and thunderstorms return Thursday and persist through at least Saturday as drier conditions arrive by Sunday.

DISCUSSION

Key message 1: Hot and muggy conditions persist through the end of the week, with slightly cooler temps behind a cold front this weekend.

The area remains underneath weak upper flow, maintaining a broad warm sector and higher dewpoints. A strong trough to the north expands southward, but guidance continues to keep the southern edge out of the area, shunting better forcing for any convection today and into Thursday. As for temperatures, summer marches on with values remaining in the 90s through Friday. Model guidance is a bit skeptical on the exact timing of a potential cold front pushing through the area. Could be as early as Friday night and as late as Saturday night. Regardless of timing, there is general consensus for a weak frontal boundary to bring a small amount of relief from hot temps and muggy conditions by the weekend and into next week.

Key message 2: Showers and thunderstorms return Thursday and persist through at least Saturday as drier conditions arrive by Sunday.

As a series of upper lows churn over Canada over the next few days, a persistent trough remains stretched out over the eastern portion of the CONUS. The better forcing remains further to the north for today and Thursday. However, as the trough dips further southward, a weak frontal boundary looks to sweep through the area by the end of the week. Model guidance is not too keen on the exact timing, but does agree on a front moving through and ushering in drier air into Sunday and beyond. Ahead of the front, shower and thunderstorm chances tick up Thursday through Saturday, especially in the mountains and NC Piedmont. Though an isolated storm or two could become strong, widespread severe weather is not expected at this time. Behind the front, drier air filters in and shunts rain chances into the new work week.

AVIATION /00Z THURSDAY THROUGH MONDAY/

At KCLT and elsewhere: VFR conditions prevail through the forecast period. Winds will go light and variable overnight and pickup out of the W to SW late Thursday morning through the afternoon, while KAVL maintains a NE component. Guidance continues to hint at a line of showers and storms moving towards the mountains Thursday morning and losing steam before reaching the area. However, there may be some lingering cloud debris during the mid to late morning hours. Can't totally rule out mountain valley fog/low stratus around daybreak Thursday, but confidence is low as to whether it gets advected far enough into KAVL, so kept any mention of fog/low stratus out of the TAF at this time. Did include a PROB30 for TSRA and associated restrictions at KAVL for Thursday afternoon, while confidence is too low for a mention at the other TAF sites.

Outlook: Afternoon showers and thunderstorms return on Thursday through Saturday. Low stratus and fog possible each morning, mainly in the mountain valleys.

GSP WATCHES/WARNINGS/ADVISORIES

GA...None. NC...None. SC...None.