Area Forecast Discussion
Issued by NWS Columbia, SC
Issued by NWS Columbia, SC
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929 FXUS62 KCAE 161031 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 631 AM EDT Fri Aug 16 2024 .SYNOPSIS... High pressure will be over the area today. As a cold front approaches the Southeast US this weekend, moisture and rain chances return. The front may stall over the region early next week leading to continued slight chances for rain, mainly near the Coastal Plain. && .NEAR TERM /THROUGH TONIGHT/... Key Message(s): - Moisture increasing today, but showers expected to stay to the west of the region. Deep upper trough over the upper Midwest will be moving east into the Great Lakes region by this evening. The upper ridge over the area will weaken a bit especially in the South Carolina Piedmont this afternoon and overnight. At the surface, the ridge axis will shift to the coast. Precipitable water increases to near 2 inches in the west/north Midlands this afternoon and tonight due to weak southwest low level flow ahead of upper trough/surface front moving into the Ohio Valley. Soundings still indicate mid level capping but weaker than yesterday, especially in the west. Surface based CAPE remains low, maybe > 500 J/kg, possibly near 1000 J/kg as suggest by HRRR in the west/north Midlands late in the day. Trigger lacking although a weak short wave may move over the ridge in the afternoon and evening. The HREF show some convection coming over the mountains and weakening near the area around 00z. PoP guidance remains low so will continue the dry forecast. Temperatures should be a degree or two warmer than yesterday as some warm advection noted at 850mb but with moisture increase, maybe a few low and mid level clouds. Continued temp forecast of highs around 90 degrees and overnight lows in the low 70s. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... Key Message(s): - Showers and thunderstorm chances return for the weekend as a cold front approaches. - A few thunderstorms may be strong this weekend with damaging wind gusts as the primary severe hazard. Cold front will still be west of the region, but moving southeastward on Saturday. Moisture is expected to be on the increase through the day, along with an increase in pops. Best chance will remain over the western cwa closer to the incoming front, mainly in the afternoon and evening hours. Although instability is not overly impressive, much of the western counties are in a marginal risk of strong to severe storms. This appears to be mainly due to the inverted-v sounding across much of the area during the afternoon. Confidence is not overly high for overall coverage, with models showing limited convection through the day. Will still continue with isolated to scattered coverage. Activity not expected to last much past sunset and the loss of heating though, and much of Saturday night will turn dry. High temperatures Saturday back into the lower 90s, while lows Saturday night remain in the lower 70s. The front actually moves into the forecast area on Sunday, and this will bring another round of afternoon scattered showers and thunderstorms as it moves through. Can not rule out additional strong convection with damaging winds on Sunday. Temperatures similar to Saturday, with highs in the low to middle 90s possible, and lows around 70. && .LONG TERM /MONDAY THROUGH THURSDAY/... Key Message(s): - The cold front may stall off the coast leading to mainly isolated rain chances over the far eastern cwa. Best rain coverage will remain in the Coastal Plain. Cold front moves east by Monday before slowly moving off the coast by Tuesday, Upper trough will set up across the region through the early part of the week. but may actually stall out near the coast. Slightly cooler and refreshing temperatures will move into the cwa, with highs in the 80s and lows down into the mid to upper 60s. Although slightly drier, guidance does have some isolated afternoon showers possible through the week, with best chances in the coastal plain associated with the sea- breeze. Majority of the cwa will remain dry though each day into Thursday. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/... Mainly VFR through the period, with the exception of brief patchy early morning shallow fog this morning at AGS/OGB. Satellite showing mainly clear skies across the area. Shallow patchy fog at AGS and OGB should erode by 13z. High pressure across the area will shift to the coast through the day. Expect and increase in cumulus by the afternoon. Mid level capping in soundings noted and high resolution models keep any showers west of the terminals, mainly in the mountains and Upstate SC this afternoon and early evening. High convective debris clouds into the evening. Winds remain light southwest to south around 5 knots. EXTENDED AVIATION OUTLOOK...Low confidence in early morning fog and stratus with brief MVFR/IFR restrictions possible at prone AGS/OGB. Widely scattered diurnally driven thunderstorms Saturday and Sunday. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...None. GA...None. && $$