353 FXUS62 KCHS 222314 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 714 PM EDT Wed Jul 22 2020 .SYNOPSIS... High pressure will persist through early next week. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... Atlantic high pressure will remain the dominant feature throughout much of the troposphere. There are enough boundaries and sufficient thermodynamics to allow for a few more showers through mid evening, mainly over our far southern and western Georgia counties. There are hints of some late night showers developing over the ocean and making a run for the coast. But any moving ashore look to be after daybreak, rather than in the tonight period. Patchy convective debris clouds over georgia will gradually fade early tonight, while some late night stratocumulus and/or cumulus move onshore the coastal zones. On average skies will be clear or partly cloudy. Temperatures will be similar to previous nights, with lows ranging from the lower 70s and middle inland to around 80-82F at the immediate coast and in downtown Charleston. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/... Thursday: A mid/upper level ridge of high pressure will persist across the Southeast United States, favoring a typical summertime pattern as the area remains positioned between sfc high pressure extending across the western Atlantic and weak lee trough inland. Few to scattered showers and thunderstorms are possible during the afternoon into early evening hours, mainly along a seabreeze initially, then well inland closer to the lee trough mid-late afternoon into the evening. High temps will generally range in the low/mid 90s, warmest along and west of the I-95 corridor. Most convection will quickly diminish with sunset with the remainder of the overnight period being dry. Lows will be mild, ranging in the low-mid 70s inland to upper 70s/around 80 along the coast. Friday and Saturday: A break in the mid/upper lvl ridge is anticipated as stronger h5 shortwave activity rounds the base of a mid/upper lvl trough of low pressure shifting across the Mid- Atlantic and Northeast states this weekend. A more pronounced lee trough should develop in response to h5 shortwave activity traversing aloft and when combined with deepening moisture characterized by PWATS exceeding 2 inches should favor greater precip coverage during peak diurnal heating Friday and Saturday afternoon into evening hours. Scattered to potentially numerous showers and thunderstorms are possible across much of the area, but especially across northern locations in Southeast South Carolina. The overall severe weather threat appears to be low this weekend, but a few stronger and/or isolated severe thunderstorms are possible. Given deep moisture and weak wind fields in place, thunderstorms could produce locally heavy rainfall. High temps should remain a few degrees lower than previous days, mainly due to the extent of afternoon showers/thunderstorms and associated cloud cover. In general, highs will range in the upper 80s/lower 90s north to low/mid 90s south. Low temps should range in the low/mid 70s inland to upper 70s/around 80 at the coast. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... Mid-level troughing is forecast to move off the Northeast coast early next week. Meanwhile, a dominant ridge will remain over the central U.S. Though, it'll get pushed to the west by Tuesday as another trough starts to move over the Northeastern U.S. Surface high pressure remains in the Atlantic with weak troughing developing inland each afternoon. The typical summertime pattern prevails with afternoon/evening showers and thunderstorms. Daytime temperatures will remain at or slightly above normal while overnight temperatures remain above normal. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... VFR will rule through 00Z Friday. There are indications of isolated TSRA at or near KCHS and KSAV along the sea breeze Thursday afternoon, roughly between 16Z and 20Z. However, no need to include any mention in the TAFs at this time. Extended Aviation Outlook: VFR conditions should prevail at both CHS and SAV terminals Thursday night. Flight restrictions associated with showers/thunderstorms are possible at both terminals Friday and Saturday, mainly during the afternoon and/or evening hours. && .MARINE... Tonight: A Southerly flow will persist tonight as the coastal waters remain on the backside of Atlantic high pressure. Winds will average around 10 or 15 kt, with seas 2 to 3 feet. Thursday through Monday: Conditions will remain well below Small Craft Advisory levels into the weekend and early next week while Atlantic high pressure prevails. In general, south-southeast winds will remain around 15 kts or less, highest near the coast where a seabreeze develops and shifts inland each afternoon. Winds should slowly turn to south-southwest early next week. Seas will be no higher than 2-3 ft into the weekend, then slowly build up to 3-4 ft early next week. && .TIDES/COASTAL FLOODING... The evening high tide will likely peak close to 7.0 feet MLLW in the Charleston Harbor. The astronomical tide is 6.34 ft MLLW, around 10:15 pm, meaning that we would need to see a tidal departure of 0.66 feet MLLW for any shallow coastal flooding. Since winds will be veering a little more S-SW at less speeds once the sea breeze influences fade by that time, our current thinking is that levels will stay just shy of the coastal flood criteria, however we will continue to monitor trends over the next few hours. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM... SHORT TERM...DPB LONG TERM...MS AVIATION... MARINE... TIDES/COASTAL FLOODING...