112 FXUS62 KCHS 261121 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 721 AM EDT Sat Oct 26 2019 .SYNOPSIS... High pressure will shift offshore into the weekend as low pressure moves north out of the Gulf of Mexico and into the Great Lakes region. A cold front will push offshore Sunday night and meander near the area through mid-week before a stronger cold front pushes off the coast by week's end. && .NEAR TERM /THROUGH TONIGHT/... As of 715 AM: Given the latest MOS trends, I will update the forecast to warm this afternoon highs by a degree. Otherwise, the current forecast appears on track. As of 4 AM: Sfc low pressure is forecast to track rapidly north across the Mississippi River valley today, reaching the Great Lakes region this evening. The warm front associated with the low will lift across SE GA and SC today. As the warm front lifts north, sfc dewpoints are forecast to increase into from around 70 inland to the lower to mid 70s along the coast. As a result, SBCAPE are forecast to increase to 1000-1500 J/kg south of the Savannah River, with 300- 700 J/kg to the north. CAMs indicate that bands of showers with embedded thunderstorms will develop near the warm front, thunderstorms should favor the coastal areas. PoPs will increase through the day, reaching low likely values south of the Savannah River by late this afternoon. Using a blend of MOS, high temperatures are forecast to range between 79-83 degrees. A cold front will approach from the west tonight, reaching from the southern Appalachians to the FL Panhandle by sunrise Sunday. Based on the timing of the front, the forecast area should remain in the warm sector through the night. Low temperatures are forecast to range from around 70 inland to the low to mid 70s along the coast. Scattered to numerous showers with isolated thunderstorms will likely linger through the overnight hours. && .SHORT TERM /SUNDAY THROUGH TUESDAY/... Moderate confidence this period. A cold front will be shifting east toward the coast during the day with numerous to widespread showers along with a few thunderstorms, ending from west to east during the day. There could be just enough instability/deep layer shear to develop a few stronger storms w/ damaging wind gusts, mainly from wet microbursts. The front will then stall just offshore Sun night with most of the rain staying away from land. A few showers could return Monday as onshore flow develops, strengthening Monday night. On Tuesday, the front just south and east of the area begins to transition to a warm front and moisture/upper forcing intensify. The heaviest rain this period should occur inland closer to the Midlands/CSRA which will help the drought situation, with a few inches possible. Temperatures will stay much above normal through the period. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... Moderate confidence through Wednesday night and low confidence thereafter. The warm front just south of the area Tuesday night will strengthen and shift northward especially later Wednesday and Wednesday night as a cold front approaches from the west. However, there is still some uncertainty regarding how fast of a frontal passage we'll see but for now we continue to trend toward a slower evolution, possibly not until Friday. Temperatures will stay well above normal through mid week ahead of the front and then should eventually get back closer to normal later in the week behind the front. && .AVIATION /11Z SATURDAY THROUGH WEDNESDAY/... Sfc low pressure is forecast to track rapidly north across the Mississippi River valley today, reaching the Great Lakes region this evening. The warm front associated with the low will lift across SE GA and SC today. CAMs indicate that bands of showers, with isolated thunderstorms, will develop near the warm front. In addition, patches of MVFR ceilings will be possible this afternoon as deeper moisture arrives from the south. I will indicate regular SHRAs at KSAV from 16Z and later, with MVFR ceilings by late this afternoon into this evening. Light showers and MVFR ceilings will likely pass across KCHS this evening. Forecast soundings and MOS indicate that the potential for IFR conditions will increase during the pre-dawn hours as the cold front approaches from the west. Extended Aviation Outlook: Flight restrictions expected at times early to mid next week as a storm system impacts the area, especially starting Monday night. && .MARINE... A warm front will lift across the marine zones today into this evening. Overnight, a cold front will approach from the west, but will remain over land by sunrise Sunday. Winds are expected to remain from the east this morning, then veering from the SE this evening to S by late tonight. Winds speeds are forecast to favor values between 15 to 20 kts. Wave guidances indicates that outer GA seas will reach 6 ft by late this afternoon and will persist through the night. A Small Craft Advisory for the outer GA waters from 4 PM this afternoon until 7 AM Sunday. Seas should range between 3-5 ft within 20 NM from shore. Sunday through Thursday: Brisk southerly winds expected Sunday ahead of a cold front, near Small Craft Advisory levels beyond 20 nm, but otherwise a weaker pressure gradient is expected through mid week with no significant concerns. && .TIDES/COASTAL FLOODING... Steady onshore winds should keep tidal departures greater than .4 ft along the lower SC coast. High tide is expected to peak around 7.1 ft MLLW by 7 AM. Coastal Flood Advisory has been issued from 6 AM to 8 AM for Charleston, Beaufort, and coastal Colleton Counties. Expect above normal tides through the middle of next week due to astronomical influences and onshore winds much of the time. Minor to moderate coastal flooding is expected along the SC coast with minor flooding along the northern GA coast. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...Coastal Flood Advisory until 8 AM EDT this morning for SCZ048>050. MARINE...Small Craft Advisory from 4 PM this afternoon to 7 AM EDT Sunday for AMZ374. && $$ NEAR TERM...NED SHORT TERM...RJB LONG TERM...RJB AVIATION...NED/RJB MARINE...NED/RJB TIDES/COASTAL FLOODING...