textproduct: Greenville-Spartanburg

SYNOPSIS

Below normal high temperatures stick around through next week. Dry and cold high pressure remains in control through Saturday before a cold front brings precipitation chances Sunday. Drier conditions develop briefly Monday before a low pressure system from the Gulf brings better precipitation chances Monday night and Tuesday. Dry high pressure returns Wednesday into Thursday.

NEAR TERM /THROUGH SATURDAY/

As of 630 PM EST Friday... Key Messages...

1) Lighter Winds Return this Evening

2) Tonight will be the Coldest Night of the Season

3) Cold and Dry with Well Below Normal Temperatures Again Saturday

Tonight, the center of high pressure passes just north of the area, supporting favorable radiational cooling conditions. High clouds will stream overhead, but they should have minimal impact on temperatures. A cold airmass and ideal cooling conditions will set the stage for the coldest night of the season thus far. Lows are expected to fall into the teens across the mountains and the lower to mid twenties across the Foothills and Piedmont.

High pressure shifts east on Saturday and moves toward the Mid Atlantic coast, but it will continue to control our weather. A weak southerly return flow develops by afternoon as warmer air begins to approach from the southwest. However, the warm advection arrives slowly, so highs on Saturday should be similar to today, mainly mid to upper 40s outside the mountains with 30s at higher elevations. A deep mixed layer should promote downward mixing of drier air again on Saturday, allowing min RHs to fall near or below 30% across much of the area. Lighter winds should limit fire weather concerns.

SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/

As of 11 am EST Friday:

Key message: Brief period of wintry precip remains possible in portions of the mountains and possibly NW NC Piedmont late Saturday night into Sunday morning ahead of a weak cold front.

SW flow remains progged to ramp up Saturday evening, along and downstream of approaching weak baroclinic zone. 45 kt LLJ will translate atop the cwfa after 06Z Sunday promoting stout winds at higher elevations. Light pcpn should be initially forced by the aforementioned LLJ, and the resultant diabatic cooling toward critical wet bulb temperatures will give rise to the chances for pockets of freezing rain to develop (after a token frozen pcpn chance on onset) mainly in the mountains by early Sunday morning. Given the transient nature of the parent sfc hipres and overall light nature of the pcpn, by the time precip becomes more likely during the day Sunday, temps in most areas should be able to warm above freezing. With the frontolytic nature of the cold front, numerous showers Sunday morning will give way to diminishing chances in the afternoon.

Sfc ridging looks to reassert itself on Monday with a CAD regime seeming more likely to develop by the end of the day. We will be watching for the likelihood of western gulf cyclogenesis on Monday and the quick return of SW flow and moisture into the Southern Appalachians. Thicker cloudiness remains fcst to overspread the cwfa, and in concert with chilly NE sfc flow, maximum temperatures will be 8-10 Deg F below the December 1st normal.

LONG TERM /MONDAY NIGHT THROUGH FRIDAY/

As of 1130 am EST Friday:

Key message 1: Precipitation redeveloping by Monday night. There remains the threat of a period of wintry weather for the NC mountains/foothills and NW NC Piedmont. Rain tapers off Tuesday afternoon, perhaps ending as a period of snow in the high mountains.

Ongoing high likelihood that the region will receive a round of briefly heavy precipitation at some point late Monday night and/or Tuesday as deepening Miller type A low affects the Southern Appalachians. Based on the 28/12Z NBM, The NC mountains northeast of the French Broad Valley, and parts of the NC Piedmont along and north of I-40 remain the locations where the better chances exist for a period of of wintry mix, with the highest p-type probability being fzra.

Dry-slot looks to punch through before 00z Wednesday bringing a fast end to widespread pcpn although cooling temps within the TN border counties will support a transition to snow showers there on the back side of the system.

Key message 2: Dry high pressure should return by late Tuesday night, with daytime temps trending milder Wed and Thu. Perhaps next round of rain will be on Friday.

Sunshine returns on Wednesday as high pressure builds atop the region with moderating return flow developing Thursday. Gulf moisture tap may return pcpn to the region on Friday.

AVIATION /00Z SATURDAY THROUGH WEDNESDAY/

At KCLT and elsewhere: VFR and dry with lighter winds expected through the 00Z TAF period. Cirrus will periodically increase at times over the terminals through the period ranging anywhere from FEW to BKN. Winds will start out NW at KAVL, becoming VRB overnight into daybreak Saturday before toggling SE by the early to mid- morning hours Saturday. Winds elsewhere will generally range from WNW/NW this evening, gradually turning more NE overnight then turning more E/ESE by mid-morning to late morning Saturday.

Outlook: Restrictions and rain chances return Sunday before dry and VFR conditions briefly return Monday. Another round of rain and restrictions are expected Tuesday before dry and mainly VFR conditions return Wednesday into Thursday.

GSP WATCHES/WARNINGS/ADVISORIES

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