Area Forecast Discussion
Issued by NWS Columbia, SC
Issued by NWS Columbia, SC
803 FXUS62 KCAE 151834 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 234 PM EDT Sun Sep 15 2024 .SYNOPSIS... High pressure extending into the region from the north will weaken as a low pressure area offshore moves toward the Carolina coast tonight into Monday. Breezy conditions and scattered to numerous showers are expected through Monday night. Moisture will remain high across the area through mid week with scattered mainly diurnally driven showers and thunderstorms. Lower chance of rain late week as drier air moves into the area. Temperatures cooler than normal early in the week then expect a warming trend. && .NEAR TERM /THROUGH TONIGHT/... Key Message(s): - Breezy conditions continue through tonight. - Rain chances gradually increase overnight, mainly for the eastern and northern portions of the forecast area. High pressure and upper ridge remain stationed over the northeast, while an off shore low is continuing to develop. As a result, a fairly tight pressure gradient across the area is causing breezy northeast winds this afternoon, with gusts in the 20 to 30 mph range. After sunset, winds are likely to lower some, but remain breezy due to the pressure gradient. A few showers are possible in the eastern portions this afternoon and evening. Rain chances are then anticipated to gradually increase overnight from the east to west as the off shore low drifts closer to the area. Rain chances are highest for the northern and eastern portions of the forecast area. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... Key Message(s): - Locally heavy rain possible in the Pee Dee Region Monday and Monday night - Gusty north winds 20 to 30 mph Monday. Monday and Monday night...Low pressure, currently offshore of SC along a stalled frontal boundary is expected to move onshore sometime Monday. Expect 18z models to have a better handle on the overall development/track with data from NHC reconnaissance mission. Notice large spread in track guidance/timing of low moving onshore, but ensembles appear to favor north coast SC and coastal NC. Although steering flow weak, latest water vapor shows a robust short wave over southeast GA/SC, which should nudge coastal low to the north. Model guidance in general suggest a weak low pressure system with some tropical characteristics. As the low moves toward the coast tonight, moisture flux/warm advection will increase primarily across the north coast SC/Pee Dee and eastern North Carolina. Precipitable water will increase likely to values above 2.00-2.25 inches in the Pee Dee. So locally heavy rain possible in that region with up to 3.00 inches. Elsewhere, qpf amounts expected to much lower. Continued a large range in pops from slight chance/chance in the CSRA, to likely in the Pee Dee. Possible sharp precipitation gradient across the area. Strong pressure gradient across the area although ridge to the north will be weakening as the low moves toward the coast, but expect gusty north winds Monday to around 30 mph possible, especially in the morning to midday. Temperatures will be cooler in the north Midlands with highs mainly in the mid 70s. Near 80 degrees in the CSRA where showers will be more limited. Stayed near the NBM mean. Lows in the low to mid 60s with showers lifting to the north. Tuesday and Tuesday night...Moisture could linger across the region for Tuesday as the low pulls away from the forecast area. A few showers will be possible but overall rain chances are lower as the deepest moisture shifts north. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... Key Message(s): - Drier weather expected for mid-week - Forecast uncertainty increases for late week As a surface low moves north of the forecast area by mid-week, relatively dry air is expected to wrap around the system and move into the forecast area. However, GEFS appears to be more moist than ECMWF/GEPS ensembles through the week. Uncertainty with regards to temps/precip. Appears blocking pattern aloft may set up with upper low remaining over the southeastern States, leading to cooler temps and higher chance of rain each day. Kept low pops through the period with mainly widely scattered diurnally driven convection with overall weak forcing. Temps near the NBM mean with warmest temps/above normal Thursday, otherwise seasonal values. && .AVIATION /17Z SUNDAY THROUGH THURSDAY/... VFR conditions into tonight before transitioning to MVFR. Breezy northeast winds gusting to 20-25 kts are expected to continue into the overnight, but easing somewhat after sunset. The winds are expected to increase again after daybreak and shift more northerly. Broken VFR clouds continue through about 05z-07z, then become MVFR for much of the rest of the TAF period. Some showers are expected to move into the area and approach the CAE/CUB/OGB terminals with IFR cigs possible late in the TAF period. EXTENDED AVIATION OUTLOOK...Scattered showers with possible restrictions at times through the day 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. && $$