textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

No major changes to the forecast.

Updated aviation section for 12Z TAF issuance.

KEY MESSAGES

1. Seasonably cool and dry conditions continue, with frost likely across portions of the area again tonight. 2. Temperatures warm again into midweek before another frontal system increases precipitation chances and ushers in much colder weather late in the week.

DISCUSSION

Key message 1: Seasonably cool and dry conditions continue, with frost likely across portions of the area again tonight.

Dry/cool surface high pressure remains over the area through tonight as a long wave trough axis steadily shifts off the East Coast. Highs will be near or slightly above normal today, but low dewpoints, light winds, and mostly clear skies will result in another night of near to a little below normal lows. Another Frost Advisory may be needed for the I-40 corridor but will not issue one at this time due to the ongoing Frost Advisory for this morning.

Key message 2: Temperatures warm again into midweek before another frontal system increases precipitation chances and ushers in much colder weather late in the week.

An low amplitude ridge develops over the region into the middle of the week. Highs rise to around 5 degrees above normal for Monday into Wednesday. Surface high pressure remains in place across the area, but low temps also slowly increase to around 5 degrees above normal by Wednesday night. That said, lows Monday night will be a few degrees below normal, keeping the potential for frost in play across the I-40 corridor.

By mid-week, a consensus of global models continues to advertise the building of a very deep ridge across the West, with a series of short wave troughs of an increasingly Arctic origin diving down the east side of this ridge carving out an impressively deep trough/upper low over the East by Friday. The associated frontal system looks to move into the area Thursday then east of the area Thursday night. The global models seem to be trending toward a surface low developing over the Midwest and moving south of the Great Lakes Thursday and Friday. The GFS remains the wettest solution with precip ahead of along the front, but the others look to be trending toward some precip across the area. There is still good agreement on the potential for cold sector/northwest flow precip, including the potential for mountain snow, at least for the higher elevations. PoPs still remain mostly in the token small chance range...except for higher chances along the TN/NC border. Otherwise, much cooler conditions are forecast for late in the week, with temperatures forecast to be 10 to 15 degrees below normal.

AVIATION /12Z SUNDAY THROUGH THURSDAY/

At KCLT and elsewhere: VFR at all terminals through the period, with clear sky, courtesy of high pressure moving in from the west. Wind has gone calm or light/variable in most places, but a lee trof should develop by midday that will bring the wind direction around to SW outside of the mtns.

Outlook: Dry and VFR through Wednesday. Some mountain valley fog/low stratus will be possible starting Monday night and early each morning after that. A cold front may bring recipitation and associated restrictions back Thursday into Friday but confidence is low at this time.

GSP WATCHES/WARNINGS/ADVISORIES

GA...None. NC...Frost Advisory until 9 AM EST this morning for NCZ035>037-056- 057-502-504-506. SC...None.