Area Forecast Discussion
Issued by NWS Columbia, SC
Issued by NWS Columbia, SC
541 FXUS62 KCAE 150004 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 804 PM EDT Sat Sep 14 2024 .SYNOPSIS... Generally low chances for rain overnight tonight. There will be a chance of showers and thunderstorms each day through early next week with deep moisture over the region. Low pressure is expected to develop offshore next week, potentially enhancing rain chances. && .NEAR TERM /UNTIL 7 AM SUNDAY MORNING/... Key Message(s): - Mostly cloudy conditions. - Periodic light showers are possible this evening. Wedge conditions will rule overnight as a polar surface high camps out over New England. Northeasterly flow will promote low clouds, as well as a few evening showers south of I-20. Most places will remain dry, however. Overnight temps will be a touch above normal thanks to the low clouds putting a lid on the terrestrial radiation loss. && .SHORT TERM /7 AM SUNDAY MORNING THROUGH TUESDAY/... Key Message(s): - Potential for subtropical low pressure formation along an offshore frontal boundary. An exceptionally strong H5 high pressure system will be over the Northeast U.S. with a frontal boundary extending from the Deep South into the Western Atlantic Ocean. Multiple synoptic and mesoscale models develop a low pressure system along this boundary which might take on subtropical characteristics. These models differ on the strength and trajectory of this surface low which greatly influences the sensible weather for The Midlands and CSRA during this time period. The Eastern and Northern Midlands have the best chance of being impacted by this potential system with a chance of showers and thunderstorms. The best estimate given the uncertainty with the low pressure system development, timing, and trajectory is a slight chance of showers on Sunday followed by a chance of showers and thunderstorms Eastern and Northern Midlands closer the low pressure system`s path on Monday. There is a chance of showers on Tuesday with residual moisture in place after the system moves into the Mid Atlantic region. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... Key Message(s): - Drying trend likely during the middle of the week. - A more uncertain forecast by Friday and Saturday. An unseasonably strong H5 high pressure system weakens during the middle of next week which allows a potential sub tropical low pressure system to lift northward into the Mid Atlantic States. Drier air on the backside of the low pressure system should usher into The Midlands and CSRA Wednesday through Thursday. The pattern becomes more uncertain toward the end of the week with a blocking pattern across the contiguous U.S. Much above normal H5 heights over the Great Lakes region may push the above mentioned but weakening low pressure system back over the Southeast U.S. for a slight chance of showers and thunderstorms. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... VFR conditions early this evening are expected to deteriorate to MVFR and possible IFR after midnight. Regional radar showing some scattered showers moving through the area which may impact the terminals through 02z or so but confidence not high enough in restrictions occurring to include more than VCSH at this time. Otherwise, not expecting much additional rain overnight. A strong pressure gradient between high pressure over the Mid-Atlantic and developing low pressure off the coast is should result in wind staying up overnight in the 5 to 10 knot range, preventing any fog concerns. Continued onshore flow is expected to result in a return of MVFR cigs in stratus after 03z from east to west which should last through 15-17z Sunday. There is a possibility of some brief IFR cigs around sunrise so have included a tempo group to handle that possibility. Cigs should return to VFR by early afternoon and winds remain from the northeast around 10 to 12 knots with gusts up to 22 knots through the afternoon. EXTENDED AVIATION OUTLOOK...Scattered showers with possible restrictions at times through Monday as moisture pools over the area along a front and low pressure near the southeast coast. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...None. GA...None. && $$