428 FXUS62 KCHS 030333 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 1033 PM EST Sat Jan 2 2021 .SYNOPSIS... A cold front will move through the area tonight. High pressure will then prevail Sunday through the middle of next week. Another low pressure system could pass across the area by late in the work week. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... An incredibly moist early January airmass is in place with Precipitable Water values ranging from 1.7 to 1.8". A weak surface wave will track northeast through our inland zones along the approaching cold front. High-res models are still in fairly good agreement that the heaviest rainfall will be across our far inland zones which is where most of the rain has already fallen. So far no flooding issues have been observed. We pared back the Flood Watch to only include the far inland GA/SC zones. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/... Sunday: the cold front and associated precipitation will be departing the region in the morning, then clearing and drier for the rest of the day. Despite low level cold air advection, the westerly flow will have a downslope component that is expected to allow highs to still reach the mid to upper 60s. Expect relatively breezy westerly winds of 10 to 20 mph through the afternoon. A surface ridge will build northwest of the area, with light northwest winds and lows dipping back into the mid to upper 30s well inland, and lower 40s closer to the coast. Monday and Tuesday: A cool, dry pattern is expected through this period. A strong upper level shortwave will move just north of the area on Monday afternoon, but moisture will not be sufficient enough to produce any precipitation. After this upper system moves by, a reinforcing high pressure ridge is expected to build back in, proving cooler temperatures, but still only near to slightly above normal. Highs Monday and Tuesday in the upper 50s to lower 60s, warmest on Tuesday. Lows Monday night in the upper 30s inland, to the lower 40s near the coast. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... Dry high pressure will prevail across the Southeast United States through at least Wednesday with high temps remaining slightly above normal (low 60s). A light southerly flow should then develop across the Southeast United States during the second half of the week as a low pressure system approaches from the west Thursday. The changing pattern should support slightly warmer temps Thursday afternoon with highs generally ranging in the mid 60s across most areas. A cold front should then shift through the area late Thursday into early Friday, bringing scattered showers across most areas. Temps will become cooler once again post fropa Friday afternoon, then persist into Saturday while a mid-lvl low departs off the Southeast Coast. In general, afternoon highs should range in the upper 50s Friday, then mid/upper 50s Saturday. Overnight lows should approach the mid 30s inland to lower 40s near the coast during the weekend. && .AVIATION /04Z SUNDAY THROUGH THURSDAY/... Showers will eventually overspread both terminals overnight as a cold front moves through. Surprisingly we've had a period of VFR conditions at both sites early this evening. A several hour period of at least MVFR ceilings and/or vsbys still seems likely late this evening and overnight once the widespread precipitation spreads in. VFR conditions will return by daybreak Sunday following the cold frontal passage. Extended Outlook: Sunday night through Wednesday night: VFR expected to prevail. Patchy late night fog will be possible, especially Wednesday night, which could produce some flight restrictions. Thursday: another storm system could be approaching from the west late, but currently, VFR expected to prevail through the day. && .MARINE... Tonight: A front will remain inland through late tonight. Low pressure is expected to track northeast across GA and SC tonight. In the wake of the low, the front will push east to the near shore waters during the pre-dawn hours Sunday. As the front remains to the west, low clouds, showers/storms, and patchy fog will persist across the waters. Once the front passes, fog and low clouds will end and winds are expected to veer from the SW and increase. Gusts to around 25 kts are possible across AMZ350 and 374 after midnight. Seas should generally range from 3-5 ft, with a few 6 ft across the outer portions of 374 and 350 around daybreak. Small Craft Advisories have been issued for AMZ350 and 374, beginning at midnight. Sunday: A cold front will be pushing through the waters in the morning, with ongoing marginal Small Craft conditions over AMZ350 and AMZ374. Expect winds/seas to fall below highlights by early afternoon, but westerly winds of 15 to 20 knots will persist through the day. Sunday night through Wednesday night: High pressure will remain centered northwest of the waters through the period. Northwest winds generally 15 knots or less, becoming northeast on Wednesday, with seas 2 to 4 feet. Thursday: High pressure will slide off to the northeast with winds veering to southeast ahead of another strong cold front, which could move through the waters just beyond the period. && .CLIMATE... Record high minimum temperatures for Jan 2: KCHS: 60/1985 KSAV: 66/2017 KCXM: 63/1985 && .CHS WATCHES/WARNINGS/ADVISORIES... GA...Flash Flood Watch until 4 AM EST Sunday for GAZ087-088-099-100- 114-115. SC...Flash Flood Watch until 4 AM EST Sunday for SCZ040-042. MARINE...Small Craft Advisory until 11 AM EST Sunday for AMZ350. Small Craft Advisory until 2 PM EST Sunday for AMZ374. && $$ NEAR TERM...JRL SHORT TERM...RFM LONG TERM...DPB AVIATION...JRL/RFM MARINE...NED/RFM CLIMATE...