textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

Precipitation amounts have trended slightly lower for the mountains, with little to no precipitation outside of the mountains.

Updated aviation section for 12Z TAF issuance.

KEY MESSAGES

1. Warm and dry through Wednesday. 2. Precipitation chances increase Wednesday night and Thursday, then linger Friday and Friday night across the mountains. Temperatures turn cold enough for a threat of snow, mainly across the higher elevations along the Tennessee border.

DISCUSSION

Key message 1: Warm and dry through Wednesday.

High pressure remains over the area through Wednesday. Thickness values remain high keeping highs up to 10 degrees above normal today and Wednesday. Lows tonight will be near to slightly above normal.

Key message 2: Precipitation chances increase Wednesday night and Thursday, then linger Friday and Friday night across the mountains. Temperatures turn cold enough for a threat of snow, mainly across the higher elevations along the Tennessee border.

Guidance remains in good agreement on the overall pattern regarding precipitation potential Wed night through Friday night. A strong upper ridge developing across the western CONUS with a series of strong short waves diving south into the eastern CONUS carving out a deep trough/upper low. The associated surface low moves along the southern Great Lakes and swings a cold front across the area Thursday. There is little to no Gulf or Atlantic moisture inflow ahead of the front. So despite the forcing, little to no precip is expected outside of the mountains. The moisture is deep enough for rain to develop across the mountains however, and PoPs remain high there. As the front occludes, a stronger low pressure center develops south of the New England coast on Friday. The flow around the low brings low level moisture into the area, along with much colder temps. The moisture and good NW winds provide the set up for a NW flow precip event. Initially, temps will only be cold enough for the rain to chance to snow across the higher elevations along the TN border. The snow levels eventually fall to the valley floors as the colder air fully infiltrates the area. Model guidance remains on the dry side. The best chance for accumulating snow remains in the higher elevations along the TN border, where a Winter Weather Advisory may be needed. For now, confidence remains low on snow amounts even as confidence is increasing on a NW flow snow event as guidance continues to show this run after run. Temps drop dramatically during the weekend, with highs falling to 10 to 15 degrees below normal with some locations approaching 20 degrees below normal. Lows will also be 10 to 15 degrees below normal with a widespread freeze developing. As a reminder, the growing season is considered done after November 11 and no freeze products will be issued for any part of the CWA afterwards.

AVIATION /12Z TUESDAY THROUGH SATURDAY/

At KCLT and elsewhere: VFR at all terminals through the period once again. Wind will be light N to NW to start, then a light SW wind will develop in late morning as a lee trof is established, and then light/variable again by nightfall as the boundary layer decouples. Eventually, some high clouds will begin to filter in from the west toward the end of the period.

Outlook: VFR again Wednesday. A cold front may bring precipitation and associated restrictions Wednesday night into Friday.

GSP WATCHES/WARNINGS/ADVISORIES

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