875 FXUS62 KCAE 161844 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 144 PM EST Tue Feb 16 2021 .SYNOPSIS... High pressure and drier air will build over the region today in the wake of the departing low pressure system. Fair weather is expected through Wednesday but will be brief as rain returns to the region Wednesday night through Friday morning with the next weather system. High pressure and drier air are expected for the weekend. && .NEAR TERM /THROUGH TONIGHT/... Clear and breezy conditions continue this afternoon as the pressure gradient over the region tightens in the wake of the strong cold front that brought us heavy rain yesterday. Westerly winds at 10-15 knots with gusts to 25 will continue throughout the afternoon, before tapering off around sunset tonight. Despite the clear skies, temperatures have not increased much due to the strong cold advection and highs will remain in the low 50s across most of the CWA. Overnight, winds will die down and slowly shift to out of the north as a ridge of high pressure slides to our north. Thanks to relatively dry air and clear skies, we will drop into the low 30s - upper 20s across the tonight but light north winds should prevent any further cooling. With the below freezing temperatures in spots and wet soil drainage, isolated areas of black ice is possible in areas where the wind did not sufficiently dry out today. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... Surface high pressure will move over the Ohio River Valley and into the Northeast on Wednesday. This will lead to ridging over the Mid Atlantic and into the forecast area (FA). PWAT values will be relatively low through the day on Wednesday supporting a dry forecast. Cloud cover will increase late Wednesday as moisture advection picks up ahead of the upper trough in the central US. Showers will become increasingly likely on Wednesday evening as warm, moist advection strengthens over the cool near-surface layer. PWAT values will rise above 1 inch Wednesday evening and range from 1.25 to 1.5 inches by Thursday morning. The axis of the upper level trough will shift slightly eastward on Thursday but remain over the central CONUS. At the surface, low pressure will develop over the Southeast and lift northward through the day. This will bring widespread showers into the forecast area with periods of heavy rain. A wedge boundary will likely be located over the FA as cool air filters in from the north. As the surface low lifts northward, there may be some erosion of the wedge. Areas north of the boundary will remain cool through the day while areas south quickly warm into the 60s. It's difficult to say where exactly this boundary will be located, but it will play an important role in the forecast. As the surface low lifts away from the region on Thursday night we will see rain taper off and dry, cool air move in from the west. Thunderstorms will be possible for much of the FA on Thursday afternoon as strong warm advection at 850mb contributes to a conditionally unstable airmass. However the thunderstorms should be elevated for areas north of the wedge boundary. Surface based convection, and the chance for severe weather, will be limited to areas near and south of the wedge boundary. This type of setup typically provides a high shear and strong helicity environment that poses a tornado threat. The NAM and the SPC SREF mean have been trending towards a wedge boundary further to the south over the past several runs. This increases confidence in elevated thunderstorms for the northern FA. && .LONG TERM /FRIDAY THROUGH TUESDAY/... A front moves through Friday morning, giving way to drier conditions. Some lingering clouds in the morning prior complete drying as high pressure moves in. Tight pressure gradient will cause for breezy conditions in the afternoon. Winds will become northwesterly with downslope flow promoting more stability. This will be the beginning of the first completely sunny weekend in multiple weeks. While it will be sunny, temperatures will likely be 5-10 degrees below average. More cold air advection through the day will allow for temperatures to dip below freezing in most areas Saturday morning. A tamer weather pattern as winds aloft become zonal. High pressure begins to move offshore Monday morning, with another trough building in from the east. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... VFR conditions in place at all TAF sits, expected to remain VFR for the majority of the TAF period. Clear skies and strong cold air advection will continue through 0z tonight. Winds are currently at 10-15 knots with gusts to 25 and should continue through this evening. VFR conditions expected overnight and tomorrow morning with clear skies and no expected visibility issues. Cloud cover begins to move into the region ahead of the next low pressure system late in the day Wednesday. EXTENDED AVIATION OUTLOOK...Growing confidence in restrictions Wednesday night through Friday as a strong low pressure system crosses the region. && .HYDROLOGY... Rainfall over the past few days combined with reservoir releases will result in continued river flooding on area rivers. Additional rises are expected late in week with yet another storm system affecting the area. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$