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Area Forecast Discussion
168 FXUS62 KCHS 230146 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 946 PM EDT FRI JUL 22 2016 .SYNOPSIS... High pressure will gradually shift offshore and persist through much of next week. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... Isolated convection near Tattnall County will fade this evening. There are hints that a little convection could arrive from the north late tonight in association with some higher Theta-E air and weak upper difluence, but probability are not sufficient enough to warrant an inclusion in the latest forecast. Scattered mid and high level clouds will move through from time to time, but on average skies will be mostly clear or partly cloudy. We`re stuck in the "Dog Days" of summer, so lows will be fortunate to reach the lower or middle 70s, upper 70s near and along the barrier islands. Light geostrophic winds and wet grounds where it rained earlier could spell some fog late tonight, especially over interior Georgia and over Allendale County in South Carolina. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/... Saturday through Monday: The area will remain influenced by subtropical high pressure centered well offshore and a powerful upper ridge centered over the Central/Southern Plains. The eastern extent of the upper ridge looks to remain strong enough across Southeast South Carolina and Southeast Georgia to modulate the daily coverage of afternoon/evening showers and tstm to slightly below normal levels for deep Summer. Pops will be limited to 20-30% through the period as a result. There are signals that some pooling of 700 hPA theta-e across interior Southeast Georgia both Sunday and Monday afternoons could support a bit more shower/tstm activity there, but this will be highly dependent on how the mesoscale environment evolves. Highs will range from the upper 80s at the beaches to the mid-upper 90s through the period with overnight lows ranging from the lower-mid 70s inland to the upper 70s/near 80 at the beaches, Downtown Charleston and around Lake Moultrie. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... The forecast area will remain on the western periphery of Atlantic high pressure while a piedmont trough sits inland. A weak front will approach from the northwest mid week but will likely stall and eventually dissipate before reaching the local area. Fairly typical summertime PoP scheme, with shower and thunderstorm coverage peaking in the afternoon/evening when instability is greatest. Temperatures forecast to be at or a couple degrees above normal through the period. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... VFR conditions are expected to prevail at KCHS and KSAV through 00Z Sunday. There could be some patchy fog/stratus across the region late tonight into early Saturday, but it is expected to remain well inland of the TAF sites. Low end chances of convection Saturday. Extended Aviation Outlook: Brief flight restrictions possible with afternoon showers/thunderstorms. && .MARINE... Tonight: A gentle to moderate SE to S breeze early under the influence of Atlantic high pressure, will clock around to the SW or even W late in response to land breeze influence. Seas will be a mix of 8-9 second swells and shorter period wind waves, with significant waves heights nothing more than 2 or 3 ft. Saturday through Wednesday: Atlantic high pressure will prevail through the period while a piedmont trough persists inland. South/southwest winds will generally be 15 knots or less, peaking in the afternoon with the sea breeze circulation and then again at night over nearshore Atlantic waters due to nocturnal jetting. Seas 2-3 feet on average. Waterspouts: Conditions look to favor another round of waterspouts Saturday morning. Low-level wind fields are a bit stronger and slightly veered compared to the past several mornings, but still well within the necessary parameters for waterspout development. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ SYNOPSIS... NEAR TERM... SHORT TERM...ST LONG TERM...ECT AVIATION... MARINE...