202 FXUS62 KCHS 191807 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 207 PM EDT Mon Aug 19 2019 .SYNOPSIS... Atlantic high pressure and an inland trough will prevail until late week when a cold front possibly affects the area. && .NEAR TERM /THROUGH TONIGHT/... Early this afternoon: No change to the previous forecast thinking. Showers and thunderstorms have developed and expanded across mostly southeast Georgia. This generally follows model guidance well so only minor tweaks have been made for the afternoon. Late this morning: Current KCLX radar imagery shows just a few light rain showers along the southeast Georgia coast. On satellite imagery it is quite easy to pick out the main feature for the day as well as the attributes of the airmass. There is a clear circulation centered across Turner, Irwin, and Coffee counties in Georgia, with ongoing convection within that center. Further to the east, morning stratus is starting to respond to surface heating and taking on a more convective appearance, including rapid development of stratocumulus in areas that were clear at day break. These cloud developments point to a very moist airmass which is supported by the KCHS RAOB which had a precipitable water value of just over 2 inches. The aforementioned weak surface low will generally meander around south-central Georgia today, helping to generate showers and thunderstorms around the center and its periphery. Models are in good agreement that the best coverage in the forecast area will be across southeast Georgia and that is where rain chances are in the 50-70 percent range this afternoon. The further east you go and the further away from the low you get, coverage will be less but should still be more than it was on Sunday. Overall, the severe threat is low thanks to an unimpressive near storm environment. We could see some pockets of localized heavy rain today, but it shouldn't be enough to cause any notable flooding concerns. Also, storm motion should be just enough to preclude effects from stationary storms. Tonight: Convection is forecast to gradually dissipate during the evening hours, lingering the latest over the inland counties. Isolated showers and thunderstorms may persist over the marine zones through the night. Using a blend of MOS, low temperatures are forecast to range from the low 70s inland to the upper 70s over the beaches. && .SHORT TERM /TUESDAY THROUGH THURSDAY/... Moderate confidence this period. Deep layer troughing will linger inland while high pressure persists offshore. It appears as though the best moisture and forcing will likely stay just west of the area at least through Wednesday but we'll continue to mention a chance of scattered showers and thunderstorms each day. Given the deep moisture and generally light low-mid level winds there will at least be a small risk of localized heavy rain/flooding. Also can't completely rule out isolated severe storms each day but conditions aren't that favorable for much severe weather due to limited instability/deep layer shear. Temperatures should be near to above normal. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... Low to moderate confidence this period. The pattern doesn't change much until a cold front possibly moves near or even into the area this weekend and stalls into early next week keeping the weather more unsettled than normal. Not expecting much more than isolated severe storms/flooding at this time. Temperatures should fall back closer to normal given the increased rain/cloud coverage. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... Regarding thunderstorm potential this afternoon, KSAV has the best chance. Current radar imagery shows showers and thunderstorms near the terminal at 18z, so the best chances will be for the next 2-3 hours. Included a TEMPO group for IFR visibility from 18-20z. At KCHS, the forecast is less certain. Showers are starting to develop but the potential for a direct hit from a thunderstorm is low. Can't rule it out but also don't think it warrants an explicit mention in the forecast. Overnight, there could again be stratus development, but the current expectation is that anything that develops will remain inland of the terminals. Extended Aviation Outlook: Periodic restrictions at KCHS/KSAV through Sat, mainly from afternoon/evening showers and thunderstorms. && .MARINE... The surface pattern will support steady south winds between 10-15 kts today and tonight. Wave heights are forecast to range between 1- 3 ft. Isolated to scattered thunderstorms are expected over the waters today and tonight. The coverage should peak this afternoon within 10 NM of shore. Tuesday through Saturday: Atlantic high pressure and an inland trough will result in mainly south/southwest winds around 15 knots or less through the period. No significant marine impacts are expected other than some stronger storms from time to time. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...BSH/NED SHORT TERM...RJB LONG TERM...RJB AVIATION...BSH/RJB MARINE...NED/RJB