063 FXUS62 KCHS 121806 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 106 PM EST Sun Jan 12 2020 .SYNOPSIS... A cold front will stall over the area today, before shifting back inland as a warm front tonight. The front will linger over or near the region through the middle of the week. Another cold front will cross the area on Thursday, followed by high pressure late week. && .NEAR TERM /THROUGH TONIGHT/... A stationary front remains along our inland areas, bringing a band of showers to these locations. Models have this front and it's showers lifting inland and to the north into tonight. There remains quite a bit of shear and both CAMs and SPC Mesoscale Analysis indicate an uptick in instability. Hence, some isolated thunderstorms are occurring and this should continue into the overnight hours. The severe risk is near zero. Temperatures are easily in the 70s within the warm sector along with some breaks in the clouds closer to the coast. Though, areas underneath the showers and at the beaches will remain a few degrees cooler. With winds easing, sea fog is forming and starting to float into the beaches. Conditions should deteriorate further tonight as showers decrease, winds become light or calm, and a very moist low-level atmosphere allows widespread fog to form, partly due to the sea fog moving onshore and stratus build down to the surface. Lows tonight will again be far above normal, averaging at least 20-25F above climo. && .SHORT TERM /MONDAY THROUGH WEDNESDAY/... The forecast area will be positioned in between high pressure over the Atlantic and a stalled front well inland through mid week. Southwest flow aloft on the western periphery of a mid level ridge will gradually flatten out and become zonal by Wednesday. The best coverage of rainfall appears to be on Monday, with the highest PoPs shifting from the coast to inland through the day. Model soundings do indicate some marginal instability so a mention of thunder has been maintained. Thereafter, isolated to maybe scattered activity is possible, but the highest rain chances will be inland of the area, in closer proximity to the better forcing. The stretch of warm and muggy conditions will continue through the period. Highs will generally peak in the mid to upper 70s each afternoon, with temperatures overnight only falling to the low 60s. For reference, these low temperature values are generally near or slightly above our normal highs for this time of year and will be within range of record high minimums. See climate section for more information. The other forecast issue revolves around fog potential. Conditions are favorable for at least patchy fog each night. In addition, any sea fog that develops could drift onshore and impact coastal locations. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... A change in the stagnant weather pattern will finally arrive on Thursday as a cold front crosses through the area. Some showers could accompany the front, but overall models hint that activity will be decreasing as it moves through. We have maintained low-end rain chances. High pressure will then build into the region Thursday night and will prevail through late week. Another cold front could approach the area on Saturday. While temperatures are not expected to be as warm as the first half of the week, they are still forecast to be above normal. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... 18Z TAFs: A stationary front meandering inland will bring impacts to both KCHS and KSAV throughout the entire TAF time period. Fluctuating conditions are expected this afternoon, followed by deteriorating conditions to IFR this evening, persisting overnight. Given the complex conditions, expect amendments, especially for changes to the timing. Conditions should start to improve towards the end of the TAF time period as VCSH develop. Extended Aviation Outlook: Periodic flight restrictions are expected in fog and stratus, especially during the overnight and early morning hours. && .MARINE... Today and tonight: Small Craft Advisories are in effect for some of the coastal waters. Marine Dense Fog Advisories are in effect for some of the coastal waters. A stationary front inland will drift north/inland through tonight, allowing winds to ease. Though, seas will be a bit slower to subside, especially the GA waters beyond 20 nm. Southerly winds bringing warm, moist air over the cooler coastal waters is causing areas of dense sea fog to form. It's expected to expand in coverage tonight. An advisory may be needed for the Charleston Harbor and the outer Georgia waters. Mariners should be prepared for navigation problems and the possible closures of the Port of Charleston and the Port of Savannah, especially tonight. Monday through Friday: South to southwest winds will prevail through mid week, with speeds around 10 knots or less. Seas will remain below Small Craft Advisory levels, with the exception being across the outer Georgia waters where the ongoing advisory will persist through Tuesday as 6 foot seas linger. A cold front is progged to cross the waters on Thursday, with high pressure to build in its wake. Winds and seas will increase as a result and a portion of the marine zones could need a Small Craft Advisory. Sea fog: The main marine forecast concern remains the potential for fog. Once fog develops, it will likely linger for an extended period of time since there won't be anything to change the overall setup. The current forecast features areas of fog Monday into Monday night, and then patchy fog through Tuesday night. It is likely that fog will become much more widespread at times and dense. Dense Fog Advisories will likely be needed at various times, and the potential for fog could persist until a cold front moves through on Thursday. && .CLIMATE... Record high min temperatures for January 12: KCHS: 61/1972 KSAV: 63/1972 KCXM: 60/last set in 1972 Record high min temperatures for January 13: KCHS: 62/1972 KSAV: 65/last set in 1972 KCXM: 63/1932 Record high min temperatures for January 14: KCHS: 62/1995 KSAV: 63/1932 KCXM: 62/1950 && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...Dense Fog Advisory until 1 PM EST Monday for AMZ350-352-354. Small Craft Advisory until 7 PM EST Tuesday for AMZ374. Small Craft Advisory until 1 AM EST Monday for AMZ350. && $$ NEAR TERM... SHORT TERM... LONG TERM...ETM AVIATION... MARINE... CLIMATE...