Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
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934 FXUS62 KCHS 051511 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 1111 AM 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/... As of 11 AM: Latest round of observations indicated that many areas have warmed to around 90 degrees with dewpoints between 75 and 80 degrees. Visible satellite indicated a well-defined land breeze across the outer SC/GA waters, advancing to the east. Over land, a field of fair-weather cumulus clouds have develop across most of the forecast area, conditions appears mostly to partly sunny. Recent runs of the HRRR indicate that the sea breeze will develop along the coast by 1 PM, slowly pushing inland through the rest of the afternoon. Forecast soundings west of the sea breeze indicates that late afternoon mixing may reach between 5-6 kft. The deep mixing should reduce afternoon dewpoints, however, values should remain in the mid 70s. High temperatures are forecast to range from the upper 90s inland to the mid 90s along the coast. The combination of the hot temperatures and elevated dewpoints, inland counties should see at least a couple of hours of heat index values at or above 108 degrees this afternoon. A Heat Advisory has been issued 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 /15Z FRIDAY THROUGH TUESDAY/... VFR conditions are expected to prevail at CHS/JZI/SAV terminals through 12Z Saturday. 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...DPB/JRL MARINE...DPB/JRL