Area Forecast Discussion
Issued by NWS Columbia, SC
Issued by NWS Columbia, SC
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942 FXUS62 KCAE 242344 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 744 PM EDT Mon Jun 24 2024 .SYNOPSIS... Hot temperatures are expected to continue into midweek. Isolated to scattered showers and thunderstorms should occur each afternoon and evening, with better coverage likely Thursday. Increasing heat impacts Friday through the weekend. && .NEAR TERM /THROUGH TONIGHT/... KEY MESSAGES: -A few thunderstorms possible east this evening. A couple of surface boundaries are being noted on radar and through surface observations. There`s a moisture boundary over the eastern portions of the forecast area. East of that boundary, dew points are around 70 while dew points west of the boundary are in the upper 50s to mid 60s. Not expecting this boundary to move all that much any more this evening into tonight. A second boundary is roughly along I-20 east of the Columbia area and sliding south. This boundary has sparked some showers and thunderstorms just east of our forecast area. As this boundary continues to slide south and likely collide with the moisture boundary, a few showers or thunderstorms could develop over the next 3 to 4 hours. Otherwise, expect overnight lows in the lower to mid 70s. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... KEY MESSAGES: -Hot conditions to continue with max heat indices of 100-105. -Widely scattered to scattered afternoon/early evening thunderstorms, greatest coverage in the southeast Midlands. The region will be located along the eastern periphery of an upper level ridge on Tuesday. At the surface, a weak front will generally stall just southeast of the area. Higher levels of moisture will persist in closer to proximity to the stalled front (southeastern Midlands) with dewpoints in the upper 60s/lower 70s and precipitable water values around 1.75 inches. However, farther inland, the airmass will be significantly drier with dewpoints bottoming out in the lower to mid 60s and precipitable water values of 1.00-1.25". As a result of the increased moisture and low level convergence, CAMs show isolated to scattered showers and thunderstorms focusing across the eastern Midlands and perhaps lower CSRA during the afternoon and early evening hours on Tuesday. Soundings show enough instability and dry air in place aloft to support a damaging wind threat with any storms that do form. Temperatures will be above normal once again, but with more of a northeasterly/easterly low level flow, expect conditions to be perhaps a couple of degrees cooler than Monday with highs in the mid-upper 90s and heat index values of 100- 105. The front will lift north of the area on Wednesday, setting up more of a southerly low level flow. Diurnally driven isolated to scattered showers and thunderstorms are possible across most areas. Slightly rising heights and the southerly flow should result in warmer high temperatures, with highs in the upper 90s in most areas. Fortunately, dewpoints should mix out enough in the afternoon to keep heat index values to 100-105 degrees. && .LONG TERM /THURSDAY THROUGH MONDAY/... KEY MESSAGES: -Highest chances of showers and thunderstorms Thursday, some possibly severe. -Increasing heat impacts expected Friday through the weekend. Models show an upper trough swinging through the area on Thursday, and an associated cold front at the surface. This should provide enough forcing to result in at least scattered showers and thunderstorms in the afternoon/evening, and perhaps be the day with the greatest rain chances in the long term. Overall shear is not that strong, but soundings show weaker capping, moderate instability and more a pronounced inverted V, suggesting the potential for a few strong/severe thunderstorms with primarily a wind threat. Ensembles are in good agreement showing a strengthening upper ridge aloft Friday through the weekend. Diurnally driven scattered showers and thunderstorms are possible each day, but knocked down the NBM POPs a bit as the subsidence aloft looks to be fairly strong. Temperatures will rise through the weekend beneath the building ridge, and heat impacts will once again become an issue. Ensembles show the ridge breaking down on Monday as an upper trough passes to the north, potentially resulting in greater rain chances and cooler temperatures. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... VFR conditions expected through the TAF period. Weak surface boundary across the southeastern Midlands this evening, with higher moisture east and south of it, while drier air exists off to its north. At this time OGB remains in the moist zone, with all other sites drier. Even with the boundary though, do not expect any showers to develop near any taf locations through the period. Winds across ags/dnl/cae/cub this evening will be more westerly before becoming light and variable overnight. At ogb south of the boundary, winds remaining more southwesterly this evening before becoming light and variable also. For Tuesday, winds at all sites more easterly around 5 knots through the day. Fog is not expected tonight due to the development of a low-level jet and the drier air in place. EXTENDED AVIATION OUTLOOK...Increasing chances for afternoon scattered showers and thunderstorms and associated restrictions through Saturday. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...None. GA...None. && $$