textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

No significant changes were made to the forecast.

The aviation discussion was updated to reflect the recent 12Z TAF issuance.

KEY MESSAGES

1. Warm late summer weather will continue into early next week with temperatures at or above normal. The situation becomes unsettled over the weekend with a series of weak fronts affecting our area into next week, though the threat for significant weather remains low.

DISCUSSION

Key message 1: Warm late summer weather will continue into early next week with temperatures at or above normal. The situation becomes unsettled over the weekend with a series of weak fronts affecting our area into next week, though the threat for significant weather remains low.

We begin with an interesting almost wedge-look alike situation today, with a positively-tilted upper ridge emanating from the mid/upper anticyclone still centered over the TN Valley region supporting a weak sfc high off the Mid-Atlantic/southern New England coastal regions. This weak sfc high isn't in a great spot and there won't be any forcing other than a light easterly flow, so any cold air damming signal should get overwhelmed by late morning. Once the sun peeks out, temps will rise above normal.

The upper anticyclone will continue to control our weather as it retrogrades to the southern Plains and Ozark Plateau region through Friday. As this happens, the atmosphere will become a bit more favorable for diurnal convection, mainly limited to the mountains on Thursday, but then with chances across the whole region on Friday. Temps should peak back up into the 90s outside the mtns, but far from heat advisory criteria. The weekend is looking perhaps a bit more unsettled as there is some indication that a sfc high moving across eastern Canada to New England would push another back-door cold front into our area by Saturday. This boundary could drop temps back down into the 80s and be a focus for more numerous showers and storms mainly in the afternoon/evening, though for now the potential for severe weather looks low. The situation gets more uncertain from Sunday onward as moisture increases with a weak upper low along the northern Gulf Coast and less of an influence of upper ridging across our area. There could be a reinforcing front moving down from the north as well. The NBM shows temps dropping down into the lower 80s for highs on Wednesday, but confidence in that happening is low at this point.

AVIATION /12Z WEDNESDAY THROUGH SUNDAY/

At KCLT and elsewhere: Low-end VFR to MVFR stratocu continues to linger across the area, which will impact terminals through at least mid-morning. Guidance hasn't handled this development well, but low- level moisture and continued easterly flow should help to keep this cloud deck around. MVFR cigs are mainly along the Blue Ridge Escarpment. However, cigs have struggled to lower to MVFR at the TAF sites, so took out any mention of BKN/OVC MVFR cigs outside of KAVL/KHKY through mid-morning. Cloud cover should gradually lift and scatter a few hours after sunrise and allow all terminals to return to VFR by late morning. Some mountain valley fog and low stratus has developed, but should stay away from KAVL this morning. Winds will be light through the period at 4-8 kts out of the east to northeast. Winds may trend more east to southeasterly by the evening. KAVL will maintain a northwest component through the morning with some potential of flipping to downvalley component with a south-southeast direction by the afternoon. Uncertainties remain for another low cloud deck overnight tonight, so will have to monitor throughout the day to see if possible restrictions return.

Outlook: Shower and thunderstorm chances with associated restrictions increase going into the weekend. Mountain valley fog and low stratus will be possible each morning.

GSP WATCHES/WARNINGS/ADVISORIES

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