textproduct: Greenville-Spartanburg

SYNOPSIS

A cold front brings precipitation chances back Thursday and Thursday night. Drier conditions return behind the front Friday into the weekend as high pressure builds in from the northwest.

NEAR TERM /THROUGH THURSDAY NIGHT/

As of 1:25 PM EST Wednesday:

Key Message #1: Showers will spread over the area from the south on Thursday and continue into Friday morning.

Mild weather will continue across our area thru tonight. Sfc high pressure will continue to move further off the Atlantic Coast to- night and tomorrow morning as a cold front approaches from the west. Low temps overnight will continue their warming trend with values actually above normal for the first time in several days. Deeper moisture will begin to spread over the western Carolinas and NE Georgia tomorrow morning as weak, in-situ wedging tries to briefly set up over our area. At the same time, broad upper trofing will approach from the west, with increasing amounts of PVA and isen- tropic upglide expected over our area. We will likely see an ini- tial round of showers concentrated over the I-77 Corridor late tomorrow morning into the afternoon. Shower coverage is expected to increase across most of our CWA during the afternoon as dynamic forcing increases out ahead of the cold front. Most of the latest guidance has the front itself moving thru our fcst area early Fri- day morning with profiles rapidly drying in its wake. Thus, precip chances quickly diminish from west to east after sunrise Friday morning. We could see a brief transition from rain to snow over the NC/TN Border region and at higher elevations in the NC mtns early Friday, however any snow flurries would be brief with little more than a dusting likely at most locations. In addition, SLY winds will strengthen over the NC mtns and especially along the NC/TN Border late Thursday into Friday. If current fcst trends continue, a Wind Advisory may be needed for a portion of this area.

SHORT TERM /FRIDAY THROUGH SATURDAY/

As of 1051 AM Wednesday:

Key Message #1: Dry conditions return Friday into Saturday with gusty winds lingering through the day on Friday

By Friday morning, a potent trough will be quickly lifting across the Appalachians into New England. At the surface, a cold front will be pushing across the area with any lingering showers ahead of the boundary quickly exiting to the east by or shortly after sunrise. Gusty northwest winds will mix to the surface within the cold advection regime with a few gusts potentially touching right at advisory level criteria across the highest elevations of the northern mountains. Given the limited duration and coverage, with the strongest winds confined to the highest peaks/ridges, will hold off on issuing an advisory at this time. Winds will quickly relax Friday evening as 850mb winds relent and surface high pressure builds into the Carolinas. The synoptic pattern evolves into quasi- zonal flow across the southern states by Saturday as a broad/flat northern stream trough slides across the Northern Plains and into the Great Lakes. Another cold front is forecast to drop into the Ohio Valley Saturday night with shallow moisture pooling ahead of the boundary perhaps fostering the development of a few isolated to widely scattered showers from northern Mississippi into central Tennessee. A stray shower may drift into the southern mountains overnight, but this will be the exception and not the rule.

LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/

As of 1116 AM Wednesday:

Key Message #1: Mainly dry forecast continues late weekend into early next week, although a few showers cannot be ruled out across the mountains as an unsettled pattern persists to our north

By Sunday morning, the broad northern stream trough will be sliding into New England while a surface cold front over the Ohio Valley drops towards the Appalachians. The front will become increasingly oriented parallel to upper flow, which may slow the progression of the boundary. Nevertheless, guidance is in fairly good agreement that a predominately dry frontal passage will occur Sunday into early Monday morning with surface high pressure building back in from the north. Forecast confidence begins to wane by early next week as the boundary becomes diffuse and stalls south of the area. At the same time, broad westerlies will envelope most of the country on the poleward side of an upper ridge centered over the Gulf. Multiple shortwave perturbations embedded within the westerly flow will pass near or just north of the area from early to mid week. While this does not appear to be an overly wet forecast by any means, occasional isolated to widely scattered showers cannot be ruled out across the mountains. Timing of these waves in conjunction with overnight cooling could yield a few instances of high elevation freezing rain, but forecast confidence is too low right now highlight any given period for light icing potential.

AVIATION /18Z WEDNESDAY THROUGH MONDAY/

At KCLT and elsewhere: Expect dry, VFR conditions to continue thru early Thursday with lower cigs beginning to spread over our area later in the morning. Expect cigs to remain in the low-end MVFR range at most terminals thru 18z tomorrow, with KCLT likely to see LIFR cigs beginning around 18z tomorrow. Rain chances also increase ahead of a cold front by late to- morrow morning. KCLT will likely see showers first, with pre- vailing -RA beginning around 15z with heavier showers and lower visby by the end of the taf period later tomorrow. The other taf sites don't carry prevailing -RA until the very end of this taf period. Outside of the mtns, winds will generally remain SWLY thru this evening becoming light and VRB to calm later tonight. At KAVL, winds will favor a light, NWLY direction this afternoon, becoming calm this evening. They will pick up from the SE later tomorrow morning.

Outlook: Showers and associated restrictions are expected Thursday into Friday, with VFR conditions returning by Friday afternoon and persisting thru the weekend.

GSP WATCHES/WARNINGS/ADVISORIES

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