Area Forecast Discussion
Issued by NWS Columbia, SC
Issued by NWS Columbia, SC
116 FXUS62 KCAE 161821 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 221 PM EDT Mon Sep 16 2024 .SYNOPSIS... Low pressure moving onshore will spread rain along with breezy conditions across mainly the central and north Midlands through tonight. Locally heavy rain possible in the north Midlands and Pee Dee tonight. The low pressure area will continue to weaken and remain across the western Carolinas through Wednesday. Linger showers and seasonable temperatures expected through midweek. Drier weather expected by the weekend. && .NEAR TERM /THROUGH TONIGHT/... Key Message(s): - Potential Tropical Cyclone 8 brings potential for locally heavy rain along the North Carolina border. - Lake Wind Advisory remains in effect through 2 AM. Potential Tropical Cyclone (PTC) 8 continues to churn near the coast or just on shore around the NC/SC border. Latest guidance has PTC 8 moving somewhere along or near the NC/SC border as it heads west northwest. Rainfall associated with PTC 8 is spreading westward into the PeeDee and northern Midlands this afternoon; however, the heaviest rain has been staying out of the forecast area at this time. That said, some pockets of heavy rain are possible this afternoon and evening, mainly in Chesterfield and Lancaster Counties. Due to the potential for flash flooding concerns in the Charlotte metro area, did go ahead with a Flash Flood Watch for the northern panhandle of Lancaster County from 8 tonight through 8 am on Tuesday. Upwards of 3" of rain is possible there. Flash flood guidance is pretty high elsewhere, so don`t think a watch was warranted for anywhere else. There will likely be a fairly sharp gradient with rainfall amounts due to some dry air being entrained into the system. Areas to the north could see 2-3", while areas around Columbia are forecast to see around 0.5" or so, and locations such as Augusta and Orangeburg might not get any rain (or very little). There also remains a decently strong pressure gradient between the center of PTC 8 and a surface high over the Northeast, which is bringing some gusty winds to the area. Winds are anticipated to gust up to 35 mph at times generally north of the I- 26 corridor, with an isolated gust higher than that possible. Therefore, have kept the Lake Wind Advisory going through 2 AM. Winds and rainfall intensity are anticipated to diminish late tonight or early tomorrow morning. Temperatures overnight are expected to be in the mid 60s for the most part. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... Key Message(s): - Lingering showers both days more likely focused in the north Midlands and Piedmont - Cooler than normal temperatures in the north Midlands/Piedmont Tuesday then warming Wednesday Vertically stacked/slowly filling mature low pressure system will be near the area, probably in the western Carolinas into Wednesday. Lingering diurnally driven showers expected to focus in the Piedmont and north Midlands Tuesday where moisture and lift more evident. In-situ shallow wedge conditions with isentropic lift expected in the SC Upstate into the Piedmont/extreme north Midlands with ridge to the north extending into the western Carolinas and surface low/front across the Midlands. Drier air may advect into the southern Midlands/CSRA but in general expect precipitable water values to remain above 1.5 inches. Upper low remains over the area Wednesday, moving slowly east. There may be an increase in moisture in weak south 850mb flow. Coupled with short waves rotating around low, lift appears sufficient for scattered showers mainly in the afternoon as diabatic heating increases leading to weak instability. Isolated thunderstorms possible mainly Wednesday with weak instability noted. Stayed near the NBM mean temps. Wide range of temperatures Tuesday with mid 70s north to mid 80s south. Temperatures warmer Wednesday into the low to mid 80s across the area. Overnight lows both nights in the low to mid 60s. && .LONG TERM /THURSDAY THROUGH MONDAY/... Key Message(s): -Trending drier for the weekend. Model ensembles in pretty good agreement with upper trough taking on positive tilt and moving to the SC coast by late Friday into the weekend. Moisture becoming more limited and surface high building into the area. Diurnally driven showers expected to be more isolated and focused near the coast. Temperatures appear seasonable then maybe slightly cooler than normal by next week. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... Generally MVFR conditions become IFR overnight before improving again after daybreak. Generally MVFR cigs continue at CAE, CUB, and OGB through about 06z, then IFR cigs are anticipated, which is later than previously forecast. A few passing showers may lower vis at CAE and CUB over the next few hours. More steady rain is then expected to move over those terminals. Confidence has decreased that OGB will see shower activity, so only have VCSH there for now. The chance for showers over or near AGS and DNL is too low to include in the TAF for now. North winds gusting to around 25 kts are expected through around 23z before transitioning to northwest winds. Winds are expected to continue veering counterclockwise and diminishing as PTC 8 passes to the east and north. EXTENDED AVIATION OUTLOOK...Drier air will push into the region this week lowering rain chances. However lingering moisture leaves the door open for early morning restrictions. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...Lake Wind Advisory until 2 AM EDT Tuesday for SCZ016-020>022- 027>029-031-037-038-115-116-135>137. Flood Watch from 8 PM EDT this evening through Tuesday morning for SCZ115. GA...None. && $$