textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

Slight uptick in snow amounts for the Smokies.

The Aviation Discussion was updated for the 18Z TAF issuance.

KEY MESSAGES

1. NW snowfall begins later tonight and continues into Saturday morning across the higher elevations along the Tennessee border. 2. Gusty winds and colder temperatures behind a strong cold front beginning today and lingers through the weekend.

DISCUSSION

Key message 1: NW snowfall begins later tonight and continues into Saturday morning across the higher elevations along the Tennessee border.

The pattern flips a bit starting today through most of the weekend as a strong trough settles in over the eastern portion of the CONUS. Meanwhile, a surface low develops across the Ohio/TN Valley and lifts northeast tonight. A cold front moving in from the west pushes into the area and ushers in the coldest air of the season. The main concern from this system is snowfall in the mountains. Model guidance continues to highlight NW flow snow at the NC/TN border, especially for the Smokies. NW flow winds and lingering moisture at the NC/TN border increases the chances for the season's first snow. While a few locations outside the Smokies could see snow accumulations, the bulk is highlighted for this location, especially above 5000ft. Models continue to hint at the possibility of higher amounts of snow accums, but confidence remains medium. At this time, this location could see 2-4" with locally higher amounts up to 6" possible. Outside the Smokies, other locations along the NC/TN border are trending down, with current guidance showing sparse amounts less than 2". One reason for the possibility of higher amounts in the Smokies is model soundings still depict some instability near the snow growth zone aloft at the highest elevations over the mountains. What this means is the potential for higher snowfall rates increases as air is lifted over the peaks. Should this occur, an uptick in snowfall amounts is possible. If there is no instability that materializes, snowfall rates would be much lower. Given the warmer temps leading up to the event, small amounts of snow could melt away before more falls, leading to minor accumulations. A Winter Weather Advisory will not be issued given the very few locations where the majority of snowfall amounts remain under 2". An SPS may be issued once snowfall begins this evening.

Key message 2: Gusty winds and colder temperatures behind a strong cold front beginning today and lingers through the weekend.

The area is still on track for gusty winds from a persistent trough over the eastern CONUS through most of the weekend. At the surface, a strong area of high pressure expands across the eastern portion of the country and into the CWA. Long range guidance does keep this area of high pressure locks into the area through Day 7. Trends continue to favor cold overnight temps Friday and Saturday night, increasing confidence for a widespread freeze. Still on track for the coldest night this season to be Saturday night with temps dipping into the very low 30s and 20s (NC Piedmont and mountains). Though slightly warmer, the general trend for overnight temps for the remainder of the forecast period remains cold. Toward the end of the forecast period (mid next week), guidance depicts height rises could warm temps. Daytime highs are trending at or just below normal through Monday/Tuesday with a slight warming trend on the horizon by midweek.

Additionally, the strong trough churning over the CWA increases wind gusts from today through most of the weekend. Guidance still keeps wind gusts over the mountains below Wind Advisory criteria. Ridgetops have a better chance of seeing 40-50 mph winds, but elsewhere, confidence decreases.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

At KCLT and elsewhere: Mostly VFR conditions prevail through the TAF period. A strong cold front moves across all terminals today/evening, increasing wind gusts from the NW. Winds prevail NW and gusts of 15-30kts at most sites through tonight. Winds diminish overnight at KGMU/KHKY. Cloud cover increases overnight for KAVL, teetering cigs VFR/MVFR for the remainder of the period. No other restrictions anticipated.

Outlook: Lingering snow showers Friday night through Saturday morning, but no impacts expected at KAVL other than the possibility of a ceiling restriction. VFR returns Sunday onward.

GSP WATCHES/WARNINGS/ADVISORIES

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