textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

The aviation forecast was updated to reflect the recent 00Z TAF issuance.

KEY MESSAGES

1. A cold front keeps shower and thunderstorm chances around through Friday, with the best coverage expected today into tonight. Dry conditions return behind the front this weekend into early next week. Highs remain above normal through the period but cooler conditions are expected behind the front.

DISCUSSION

Key message 1: A cold front keeps shower and thunderstorm chances around through Friday, with the best coverage expected today into tonight. Dry conditions return behind the front this weekend into early next week. Highs remain above normal through the period but cooler conditions are expected behind the front.

Widespread showers and drizzle continue this evening as a cold front approaches the area. To the west, a well-defined band of convection appears to be losing steam...though still impressive for November...as the loss of daytime heating cuts of its supply of unstable air. Hi-res guidance remains in good agreement that convection will continue to lose steam entering the western Carolinas over the next few hours, possibly producing a round of heavy rainfall over the eastern half of the area, but likely falling apart completely over the I-77 corridor after midnight. Whatever low-end severe threat we once had appears to be virtually over for the evening.

There will, however, be a low-end hydro threat, mainly across the southern Blue Ridge Escarpment and South Carolina mountains, where southeast upslope flow will act to enhance rainfall rates. Rainfall amounts for these zones should range from mostly 1.5-2.0 inches but locally higher amounts from 2.5-3.5+ inches are possible. Rain fall amounts elsewhere should mostly range from 0.25 to 1.0 inches thanks to 30-35+ kts of deep layer shear keeping shower activity moving.

The cold front slowly pushes east across the GSP forecast area Thursday into Friday but rain chances will not be as widespread. Most of the North Carolina mountains should see dry conditions return, especially on Friday, as the front pushes east of the mountains. Rain chances will linger east of the mountains through Friday. No hydro threat is expected Thursday into Friday thanks to lower coverage of activity. With the 15Z RAP showing 500-1,000 J/kg and 25-35+ kts remaining in place ahead of the front on Thursday, embedded thunderstorms can be expected again. Deep layer shear increases ahead of and along the cold front on Friday, ranging from 40-50+ kts. This combined with lingering instability east of the mountains should keep embedded thunderstorms around. Above normal temperatures remain in place through Friday ahead of the front.

Dry conditions finally return this weekend into early next week as surface high pressure builds into the region behind the departing front. Cooler temperatures return behind the front starting this weekend but will remain above normal for this time of year.

AVIATION /00Z THURSDAY THROUGH MONDAY/

At KCLT and elsewhere: Murky conditions tonight as a cold front and associated band of showers approaches from the west. Guidance is in decent agreement that showers will gradually break down crossing the area, resulting in little to no TS, but a period of heavier SHRA at most sites the first half of the night...handled with TEMPOs in all six 00Z TAFs. Patchy IFR fog and widespread IFR to LIFR ceilings are expected in the wake of the showers, persisting into the first part of Thursday morning, before gradually scattering out through mid-day. Winds will remain S/SE through the overnight period, becoming more SW during the day on Thursday.

Outlook: Restrictions may return in many places on Thursday night. Consistent improvement is not expected until late Friday, when the cold front moves to our east and ushers in VFR conditions for this weekend.

GSP WATCHES/WARNINGS/ADVISORIES

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