Area Forecast Discussion
Issued by NWS Columbia, SC

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000 FXUS62 KCAE 280725 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 325 AM EDT Sun May 28 2017 .SYNOPSIS... Ridging over the region will weaken on Sunday as a frontal boundary slowly slides into the area. The front will stall over the area early this week providing chances of showers and thunderstorms each day through Saturday. && .NEAR TERM /THROUGH TONIGHT/... Upper ridge to our south, with upper trough over the central CONUS. A series of upper impulses will move east, tracking mainly just to our north. Surface wave over NC with surface front/trough stretching back to the west, appears will generally remain in place due to nearly parallel flow aloft. Combination of better moisture, upper energy and surface boundary providing focus for clusters of thunderstorms along this area. Activity is dissipating as it approaches our FA due to a drier and more capped atmosphere. In the near term, most high resolution model output generally suggests that cluster of thunderstorms to our WNW will gradually weaken as the activity shifts to the ESE, remaining outside our FA. Some varying solutions in latest high resolution models regarding convection later today. Old outflow boundaries from previous convection could prove important today as far as a focusing mechanism for convection, with some uncertainty on placement and timing. Cloud cover from previous convection could also affect convective potential. Atmospheric moisture is expected to increase some over our FA with some weakening of the mid level cap expected. Strong instability and considerable deep layer shear forecast today. Mid level cap still evident in soundings but not as strong as yesterday. Temperatures expected in the lower 90s to support isolated to scattered convection with a severe threat. Damaging winds appear to be the primary threat given freezing level around 15kft and fairly unidirectional hodographs. SPC has FA in a MRGL risk for severe. Used a model blend on POPs, which provides generally slight chance south to chance central and north FA. && .SHORT TERM /MONDAY THROUGH MONDAY NIGHT/... Upper level ridge will remain to our south, with upper trough to our north. Westerly flow aloft with embedded impulses. Surface low pressure well to our N/NE will shift farther NE and bring down a weak surface boundary slightly farther south into the northern/central FA, along with some continued increase in moisture. Model blend yields chance POPs. Strong instabilities Monday will provide a severe threat. SPC has region in SLGT risk for severe Monday. && .LONG TERM /TUESDAY THROUGH SATURDAY/... No changes made to the ongoing forecast for this time period. Previous discussion follows: Models are in good agreement through the long term with some differences in location on Friday and Saturday. Frontal boundary will remain stalled over the region through the period with potential for convection each day. Tuesday currently presents some concern as instability will be moderate...pwat values around 1.6 inches and SPC slight risk for the area. Chances of convection will continue Wednesday through Saturday...however with the front becoming more diffuse across the region potential for severe convection is currently lower. Temperatures will be near to slight above normal with afternoon highs in the mid 80s to low 90s and overnight lows in the mid 60s to around 70. && .AVIATION /07Z SUNDAY THROUGH THURSDAY/... VFR conditions generally expected through the 24 hr forecast period. Another 25 knot low level jet is forecast which along with convective debris clouds should limit fog development. A light southwest wind should prevail through the predawn hours and then pick up to around 10 to 12 knots with gusts to 20 knots possible after 16z. A frontal boundary will approach the forecast area on Sunday bringing a chance of showers and thunderstorms, although the best chance will be north of the TAF sites, so have not included mention for now. EXTENDED AVIATION OUTLOOK...A cold front will stall in the region through early next week. The front will help support scattered thunderstorms and associated restrictions. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$ is the U.S. government's official web portal to all federal, state and local government web resources and services.