899 FXUS62 KGSP 091834 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 234 PM EDT Sat Oct 9 2021 .SYNOPSIS... Moisture lingers over portions of the Carolina piedmont tonight as a surface low pressure center moves north along the Carolina Coast. Dry high pressure builds in on Sunday and remains in place through the week with warming temperatures. A cold front is forecast to arrive at the end of the week. && .NEAR TERM /THROUGH SUNDAY/... As of 215 PM: Strong high pressure is present over New England and the Canadian Maritimes. An upper trough extends from the eastern Great Lakes across the Carolinas. Sfc low pressure accordingly is present off the NC coast, on the periphery of the high; it will help drive breezy northeasterly winds this afternoon across much of the area. A stubborn layer of low-based stratocu is expected to persist most of the day over the eastern half of the FA, a manifestation of midlevel subsidence inversion and abundant moisture beneath it. A few showers are present along the edges of this airmass and near the east-facing Blue Ridge. The best chances will remain there thru the afternoon, via differential heating and the terrain enhancement. Still looks like a stray thunderstorm could fire up as well, with lapse rates decent aside from the subsident layer. A drying trend will continue tonight as heights rise from the west, associated with sharp ridge building in behind the aforementioned trough. That said, temperature profiles aloft don't look to change much, and easterly flow will continue in the low levels. Thus patchy stratus or stratocu may linger under the inversion, particularly in the east. Even if cloud cover remains sparse, winds should keep the PBL mixed enough to preclude fog for most of the Piedmont. Mountain valleys and the foothills however look sheltered enough for a patchy fog mention. Generally sunnier skies are expected for Sunday as drying continues; slight backing of PBL winds implies diminishing moisture flux there to boot. Max temps will be warmer overall, particularly in the areas affected by the greater cloud cover today. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... As of 1255 PM Saturday: An upper level ridge becomes dominant over the SE CONUS thru the period. However, an offshore low, perhaps becoming tropical in nature, will persist into Mon and maintain e/ly moisture flux toward the FA. The latest GFS/NAM soundings show too much downward motion for a sigfnt precip chance, yet morning fog and low-level StCu will be possible Mon morning and to a lesser extent Tue morning mainly across the ern zones. With good afternoon insol expected both days, max temps will have no problem reaching a few degrees abv normal. Mins will also hover abt 5 degrees abv normal. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... As of 130 PM Saturday: Little change was made to the ext fcst. The models still bring a weak cold front to the NC mtns Tue night, however, the overall forcing remains low and less moisture is available than was progged on previous model runs. Thus, have kept the fcst dry during this timeframe. A 590 dm upper ridge reasserts itself over the area Wed, which will remain in control of the pattern until a deep Midwest trof swings a cold front toward the NC mtns Fri night. Plan views show decent sbCAPE ahead of this feature for the time of day and enuf confidence is had to introduce isol general thunder thru the overnight. With PWATS persisting within normal climo values, expect good heating to keep max and min temps up abt 5 degrees abv normal each day. && .AVIATION /19Z SATURDAY THROUGH THURSDAY/... At KCLT and elsewhere: A persistent weak inversion has limited mixing so far today, while low-level moisture is abundant. These conditions are associated with an easterly flow regime driven by offshore sfc low and high pressure to our northeast. Stratocu layer at MVFR level is widespread across the region, with KCLT/KHKY still seeing restrictive cigs at issuance time. At least brief return to MVFR can't be ruled out at the other sites, but most likely they will remain VFR. A few SHRA will develop, especially near the east-facing Blue Ridge Escarpment, but chances at all TAF sites are small enough to omit. Breezy NE winds with occasional low-end gusts. The pattern will remain largely unchanged tonight; cloud bases are likely to lower to MVFR even if they are too sparse to form a cig. Seeing a weak signal for valley fog and IFR stratus so have retained TEMPO LIFR at KAVL. Drier profiles tomorrow under VFR and somewhat lighter winds. Outlook: Relatively settled conditions will return to the area for a few days. However, abundant low-level moisture will persist, and low cigs/fog may occur again Sunday night, at least across portions of the NC Piedmont. But otherwise, should be dry and VFR Sunday and heading into early next week. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...DEO NEAR TERM...Wimberley SHORT TERM...SBK LONG TERM...SBK AVIATION...Wimberley