textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

No significant changes were made to the forecast.

The aviation discussion was updated for the 12z TAFs.

KEY MESSAGES

1. Warm late summer weather will continue, with shower and thunderstorm chances increasing through the weekend. The risk for impactful weather appears low until we get to early next week.

DISCUSSION

Key message 1: Warm late summer weather will continue, with shower and thunderstorm chances increasing through the weekend. The risk for impactful weather appears low until we get to early next week.

Through the morning hours, the development of an easterly low level flow behind the back door cold front, now well to our south, should result in the development of cloudiness and a few showers starting near the Blue Ridge Escarpment and spreading outward from there. The evening shift raised precip chances over the NC foothills and they might have to be raised a bit more, but at least any rain should be beneficial.

A fairly interesting, but ultimately benign, slow evolution of the weather pattern is expected over the next week or so. The mid/upper anticyclone over the TN Valley region this morning should drift back to the west slowly through Wednesday night, but with a ridge axis extending across the central Appalachians to the Mid-Atlantic. This will continue to support a weak elongated sfc high off the Mid-Atlantic to New England coastal region that will more or less maintain the weak and dry cold air damming regime of sorts over our region. The effect will be minimal as moisture is lacking and support for precip is also lacking. So, as temps cool back down close to normal for today, in part due to an expected late start with some morning clouds and a few showers, that won't last long. Air mass modification will allow for a steady increase in high temps through the week, back up into the 90s by Thursday and Friday. We aren't done with summer yet. By Thursday we get right back to the summertime climo precip probs with chances over the mtns, and the precip probs expand outward and upward each day through the weekend. None of this looks terribly significant at this point.

Once we get into early next week, the situation may change a bit depending on what happens with a weak mid-level low that tracks westward across the FL peninsula and then possibly stalls over the nrn Gulf Coast on Monday. At a minimum, better moisture flux from either the Atlantic or the Gulf is expected by Monday, so precip probs increase accordingly. Confidence is too low out on the Day 6-7 periods, but suffice to say the threat for excessive rain will start to creep upward.

AVIATION /12Z TUESDAY THROUGH SATURDAY/

At KCLT and elsewhere: Stratus has already developed over portions of the area as a backdoor front slides further south from the region. Cloud bases have lowered to MVFR, with sporadic IFR possible. Placed a prevailing line for MVFR cigs at all TAF sites, but confidence is too low for an IFR mention at this time. Can't rule out an isolated shower at through mid-morning, but confidence is too low for a TAF mention at this time. The low stratus will gradually lift and scatter out late this morning into the early afternoon. This will bring a return to VFR conditions by this time, with some lingering VFR cu and mid to high clouds around through the afternoon and evening. Winds are mostly east to northeasterly at 5- 10 kts and could get as high as 8-12 kts around daybreak before losing steam by this afternoon behind the front. Guidance has hinted at possible stratus overnight again across portions of the area, which could lead to some instances of restrictions, mainly over KAVL and possibly the Upstate sites.

Outlook: Mostly dry conditions are expected to persist through the middle of the week. Shower chances and associated restrictions increase later in the week. Mountain valley fog and low stratus is possible each morning through the week.

GSP WATCHES/WARNINGS/ADVISORIES

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