286 FXUS62 KCHS 010132 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 932 PM EDT Sun Jun 30 2019 .SYNOPSIS... Through next weekend, a surface trough of low pressure will persist under a ridge of high pressure aloft. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... A surface trough in the lee of the Appalachians will shift southeast toward the forecast area overnight. Isolated convection could persist along the wind shift upstream. Relatively dry H850 to 500 MB layers, an offshore flow developing in the boundary layer and very warm temps aloft should preclude any anything more than a spotty shower late tonight and we maintained a dry forecast. Temps should remain warm overnight and we did not make any significant changes to the forecast. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... Monday through Wednesday: July will start with above-normal temperatures featuring highs in the mid/upper 90s away from the beaches. Average dewpoints will creep upward each day, and maximum heat index values in the lower 100s Monday will increase to 105-108F Wednesday. Heat Advisories are not anticipated, however, as our minimum criteria for Advisories increases to 110F Monday, July 1. Meanwhile, signals for diurnal convection are somewhat mixed through midweek. While the persistent surface trough should favor diurnal convection, the influence of an upper ridge will within a broad cyclonic flow regime cannot rule out isolated showers/thunderstorms near mesoscale boundaries anywhere Monday afternoon/evening. However, because a slightly drier environment will shift into the region from the north/northeast, the latest forecast limits isolated/diurnal convection to southern counties for a few hours Monday afternoon. Tuesday, slightly greater moisture should translate to at least isolated showers/thunderstorms during the afternoon/evening, especially along the sea breeze. Wednesday, while the overall environment should support greater coverage of diurnal convection, the capping influence of the upper ridge could still limit coverage, so PoPs are capped at slight chance/low chance during the afternoon/evening. Instability could support a threat for isolated/brief pulse severe thunderstorms Tuesday and Wednesday afternoon. However, the overall severe threat should remain low through midweek. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... At the sfc, lee troughing will persist inland while a large mid/upper lvl ridge of high pressure remains centered over the Southeast United States. The setup will favor warm conditions across the area through late week as light southerly flow at the sfc occurs below a light west/northwest flow aloft. Although high pressure will dominate aloft, substantial heating could produce a few afternoon showers or thunderstorms Thursday, especially across inland areas closer to the lee trough. Latest 1000-850mb thickness levels suggest temps approaching the mid/upper 90s Thursday afternoon, before some mid-lvl energy approaches from the west/northwest and potentially brings greater chances of showers and thunderstorms through the weekend until a weak front approaches the area Sunday. However, high temps should still approach the low/mid 90s away from the immediate coast this weekend and early next week. Overnight lows will be mild, generally ranging in the mid 70s inland to upper 70s near the coast. && .AVIATION /01Z MONDAY THROUGH FRIDAY/... VFR through 00Z Tuesday at KCHS/KSAV. Extended Aviation Outlook: VFR conditions should prevail at both KCHS and KSAV terminals. As usual during early July, brief flight restrictions/gusty winds are possible within thunderstorms, especially during the afternoon/evening hours. && .MARINE... Tonight: Winds will veer to the southwest and then west late as a trough approaches from the northwest. Winds will surge somewhat with speeds near 15 kt and seas mostly 2-3 ft, although possibly reaching 4 ft toward the Gulf Stream. Monday through Friday: Winds/seas will remain below Small Craft Advisory levels through late week. Seas of 2-4 feet Monday will settle back to 1-3 feet for the remainder of the week. && .TIDES/COASTAL FLOODING... There will be a risk for at least minor coastal flooding across the coastal counties during the evening high tides Monday through Wednesday or Thursday due to the approaching perigee, new moon and periods of onshore winds. Coastal Flood Advisories could be needed. && .EQUIPMENT... KCLX radar will remain out of service until Monday at the earliest. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM... SHORT TERM...SPR LONG TERM... AVIATION... MARINE... TIDES/COASTAL FLOODING... EQUIPMENT...