Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
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745 FXUS62 KCHS 051758 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 158 PM EDT Fri Jul 5 2024 .SYNOPSIS... High pressure will persist through Friday, then a weak cold front will stall over the area this weekend and linger through the middle of next week. && .NEAR TERM /THROUGH TONIGHT/... Early this afternoon, visible satellite and sfc observations indicated that the sea breeze will pushing inland from the coast. Temperatures across the forecast area have reached into the low to mid 90s, with another hour to two of heating left. Heat index values have warmed between 105 to 110 for most locations. A Heat Advisory will remain for many counties until 8 PM this evening. Given a convective temperature in the mid 90s, isolated to scattered showers and thunderstorms are possible late this afternoon and evening across SE GA. Tonight: Any convection that has developed and/or drifted across far inland zones should struggle to persist given a loss of diurnal heating and weak shear in place. Those that do persist, could last an hour or two post sunset, mainly due to outflow boundary interactions. The rest of the night will remain rather quiet, but mild ahead of a front approaching from the northwest this weekend. In general, lows should range in the mid-upper 70s inland to lower 80s at the beaches. && .SHORT TERM /SATURDAY THROUGH MONDAY/... The upper ridge will be centered over northern Florida on Saturday while a weak shortwave rotates around the northern periphery during the afternoon. A weak cold front is forecast to drop southeast into the area during the day, then stall nearby through early next week. The greatest moisture and instability will be across inland areas on Saturday which is where we show the greatest coverage of showers and thunderstorms. High temps in the mid 90s with mid/upper 70s dewpoints will produce heat indices 105-110F for several hours during the afternoon in most locations. Dewpoints could mix out just enough far inland to keep heat indices below 105 in those areas. A Heat Advisory will likely be needed for much of the area. Additional shortwaves moving in from the west Sunday and Monday will break down the upper ridge, reducing high temps by a couple degrees. The deep moisture is expected to expand eastward, with the entire area under at least 2.1" PWATs. Considerable coverage of showers/tstms expected both days. && .LONG TERM /MONDAY NIGHT THROUGH THURSDAY/... A fairly wet pattern likely to persist for much of next week due to deep tropical moisture in place, continual shortwaves, and a weak convergence axis along the decaying cold front. The greatest coverage should be during the afternoon and evening hours. Wednesday looks like the hottest day during this period, with the potential for Heat Advisories. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... Prior to the 18Z TAFs: Visible satellite and sfc observations indicated that a sea breeze was just inland of KJZI, approaching KCHS and KSAV. The sea breeze is expected to pass over KCHS and KSAV during the mid-afternoon hours, shifting winds from the south. Terminals should remain VFR and convection free through tonight. On Saturday, conditions should become unstable early in the day as a front approaches from the west. KSAV TAF will feature a mention of VCSH by 17Z. Extended Aviation Outlook: Brief flight restrictions are possible in showers and thunderstorms, mainly in the afternoon and evenings, this weekend through the middle of next week. && .MARINE... Today and Tonight: After some nocturnal surging weakens early this morning, high pressure extending across local waters from the northeast along with lee troughing taking place well inland should favor a modest pressure gradient across local waters. In general, southwest winds will turn more south-southeast this afternoon, peaking around 15 kt, highest near the coast where a seabreeze develops and shifts inland. Overnight, a slightly weaker southerly wind takes place (10-15 kt) with high pressure continuing across local waters well in advance of the approaching front this weekend. Seas will range between 2-3 ft through tonight. Saturday through Wednesday, a typical summertime pattern will persist, with prevailing southerly flow and winds/seas well below advisory thresholds. Rip Currents: A swell of 2 feet every 10 seconds and proximity to the new moon will maintain a Moderate Risk for rip currents for all beaches today, and likely through Saturday due to lingering 2-3 feet swell every 9 seconds and onshore winds. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...Heat Advisory until 8 PM EDT this evening for GAZ087-088-099- 100-114-115. SC...Heat Advisory until 8 PM EDT this evening for SCZ040-042>045- 052. MARINE...None. && $$ NEAR TERM...NED SHORT TERM...JRL LONG TERM...JRL AVIATION...NED MARINE...DPB/JRL