textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

Updated the aviation discussion for the 00Z TAF issuance.

KEY MESSAGES

1. In the wake of a strong cold front, temperatures will be much cooler across the area through the weekend. Much of the NC mountains will drop down below freezing tonight and widespread frost is expected in extreme northeast GA, the upper French Broad Valley, and the NC foothills.

DISCUSSION

Key message 1: In the wake of a strong cold front, temperatures will be much cooler across the area through the weekend. Much of the NC mountains will drop down below freezing tonight and widespread frost is expected in extreme northeast GA, the upper French Broad Valley, and the NC foothills.

The season shifting cold front is now well southeast of the area as we enter the first true post-frontal regime of the season. Strong continental surface high (1030+ mb) moves into the northeastern CONUS tonight and remains locked in through the rest of the weekend. A developing Nor'Easter off the North Carolina coast keeps a relatively tight pressure gradient over the region, allowing for steady low-end gusty winds to remain in place through Sunday. Clouds are expected to clear out by tonight, so radiational cooling should be effective enough to allow the higher elevations to slip at or below freezing for overnight lows. Sheltered valleys and regions away from the Thermal Belt will be in a good position for frost to develop before daybreak Sunday. Decided to keep the current Freeze Warnings and Frost Advisories for tonight in their current state as temperatures hold steady compared to the previous forecast. Another round of good radiational cooling is expected for Sunday night, so additional advisories may be needed depending on how tonight turns out.

After this weekend, the upper pattern remains relatively the same as an upper low closes offshore the Mid-Atlantic Coast and a mid/upper anticyclone churns over the Southern Plains. The upper low is expected to settle offshore the northeastern CONUS through midweek. Surface high weakens later Sunday into early next week, helping to relax the pressure gradient and allows any lingering gusts to mostly subside. Gradual air mass modification allows for temperatures to uptick each afternoon after Sunday as temperatures return to near or slightly above normal by the second half of the forecast period.

AVIATION /00Z SUNDAY THROUGH THURSDAY/

At KCLT and elsewhere: VFR conditions will prevail at all terminals in the wake of a cold frontal passage. Low fair weather cumulus clouds will dissipate over the next hour or two with low-end gusts continuing for the next hour or so as well. Gusts should subside overnight before returning again through the day on Sunday as winds remain out of the north.

Outlook: Dry, VFR conditions expected for most of next week. Mountain valley fog and low stratus will be possible each morning.

GSP WATCHES/WARNINGS/ADVISORIES

GA...Frost Advisory from 1 AM to 9 AM EDT Sunday for GAZ010-017. NC...Frost Advisory from 1 AM to 9 AM EDT Sunday for NCZ035-064-065- 501>507-509. Freeze Warning from 1 AM to 9 AM EDT Sunday for NCZ033-048>053- 058-059-062-063. SC...Frost Advisory from 1 AM to 9 AM EDT Sunday for SCZ101>103.