353 FXUS62 KCHS 282241 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 641 PM EDT Thu Jul 28 2022 .SYNOPSIS... High pressure will prevail through the weekend. A weak front will stall near the area early next week, then dissipate. High pressure will rebuild mid to late next week. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... Strong and deep layered sub-tropical ridging will prevail through the night, which will limit the amount of convection to just isolated showers and maybe a stray t-storm this evening, mainly south and central sections. The rest of the night will be rainfree, with maybe a few showers or a t-storm brushing the South Carolina coast late. However, the steering flow looks to keep the better convergence and isentropic lift over the ocean, so no PoPs are necessary over land. There is enough mixing again to prevent temps from dropping any lower than the mid and upper 70s, with even some spots along the barrier islands and in the Charleston metro not falling below 80-82F. Satellite pictures show a fairly large Saharan Air Layer (SAL) across parts of the southwest Atlantic, Florida and the western Gulf of Mexico. We're near the peak of the SAL season which typically runs through mid August. Although the NASA Aerosol forecast does show the bulk of the dust staying south and offshore tonight, recent satellite trends suggests that some of it could reach into our region. Previous discussion... Expect deep high pressure to generally prevail. Seeing a few showers in GA so far this afternoon and could see a few more into early evening across the region as instability peaks and the sluggish sea breeze moves inland. Should then be mainly dry the rest of the night, with the best chance of any rain shifting closer to the coast and offshore where the higher instability will occur. A decent breeze will also persist much of the night due to the inland trough and sea breeze, especially near the coast. Lows inland should range from the mid to upper 70s with lower 80s along the coast. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/... A fairly persistent deep layered ridge will remain the dominant feature through the weekend. However, a few shortwaves will brush the northwestern zones from time to time, and a weak lee trough will exist at the surface. Isolated to scattered mainly diurnal showers and tstms expected, especially inland. With highs well into the 90s and dewpoints in the 70s, heat indices will top out in the 105-108F range each afternoon. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... The upper ridge will shift to the east early next week, allowing a cold front to drop into central SC and stall out. Weaker mid- level subsidence and potential forcing along the front should increase diurnal convective coverage, especially Tuesday through Thursday. Heat indices will continue to top out in the 105-108F range. && .AVIATION /00Z THURSDAY THROUGH TUESDAY/... Isolated convection near KSAV will end this evening, and the risk already looks to be done with at KJZI and KCHS. Thus we have a rainfree forecast with VFR conditions at all sites tonight and Friday morning. The potential for any SHRA/TSRA Friday afternoon is too low to include with the TAFs this far in advance. Extended Aviation Outlook: VFR. Low chance for flight restrictions in afternoon/evening showers and thunderstorms over the weekend and early next week. && .MARINE... Tonight: Fairly typical summertime conditions expected with modest SW winds around the western edges of Atlantic high pressure. An inland trough will keep winds enhanced a bit more than normal and could even see some gusts near 25 knots. Confidence was not high enough in duration of the stronger wind gusts but can't rule out the need for a marginal Small Craft Advisory for at least a portion of the local waters. Seas should average 2-4 feet through the period, except up to 5 ft off the northern portions of the Charleston County coast. Friday through Tuesday: A relatively persistent south to southwest flow will persist as high pressure remains off the coast and a weak surface trough lingers inland. Speeds will average 10-15 knots, although occasional increases into the 15-20 knot range are likely at times. Seas will mainly be 2-4 feet. Rip currents: A moderate risk continues into Friday mainly due to 2 ft swell every 9-10 sec. Periods will decrease a tad over the weekend, potentially reducing the risk. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM... SHORT TERM...JRL LONG TERM...JRL AVIATION... MARINE...