374 FXUS62 KCHS 312340 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 640 PM EST Fri Jan 31 2020 .SYNOPSIS... A storm system will affect the area tonight followed by high pressure through early next week. Another storm system is expected to impact the area mid to late next week. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... As of 635 PM: KCLX detected a band of moderate to heavy rainfall lifting north across the SC Lowcountry. In the wake of the rain band, rainfall should become light. I will update the forecast to adjust PoP, rain intensity timing, and increase QPF by .1-.2 over the CHS Tri-county. In addition, I will update hourly temperatures to indicate nearly steady to slowly cooling temperatures. Previous Discussion: An area of low pressure will deepen as it lifts up the Southeast coast tonight. By daybreak, the low should be positioned roughly east of the Outer Banks. As it pulls away, the deepest moisture and best forcing will move with it. We have the highest rain chances this evening then quickly decreasing from southwest to northeast overnight. Temperatures really won't move too much from where we are late this afternoon. Lows will range from around 40 inland to mid 40s at the coast. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/... Moderate to high confidence this period. High pressure will slowly build into the area this weekend and early next week behind a departing cold front early Saturday. Although most of the deep moisture will be offshore Saturday morning, sufficient moisture will linger for cloudy skies and possibly even a few very light showers into Saturday night before the upper trough moves through. High pressure will then build the rest of the period with dry, warming weather. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... The broad ridge will shift farther to the east on Tuesday while a potent upper trough digs across the central U.S. A storm system is expected to affect the area Wednesday night through Thursday night. Strong forcing and unseasonably high atmospheric moisture content will support widespread showers and possible thunderstorms during this period. Well above-normal temperatures are likely to continue for much of the period. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... Prior to the 0Z TAFs, KCLX detected a band of moderate to heavy rainfall lifting north across the SC Lowcountry. The passage of the rain band will likely support KCHS visibility to vary between 2SM-6SM. Ceilings at KCHS and KSAV should remain between IFR-LIFR through mid-evening, with a brief period of MVFR possible in the wake of the rain band. The rest of the night should feature IFR to LIFR ceilings with 6SM with periods of mist. Based on MOS and forecast soundings, ceilings are timed to lift to MVFR late Saturday afternoon. Extended Aviation Outlook: High confidence in VFR conditions through at least Tuesday with low confidence in restrictions possibly starting Tuesday night as low-level moisture increases ahead of the next storm system. && .MARINE... Tonight: Low pressure will lift up the Southeast coast tonight. An enhanced pressure gradient as this passes by will bring a brief wind surge this evening, and Small Craft Advisories are now in effect for both the Charleston county waters and outer Georgia waters. Elsewhere, conditions should stay just shy of advisory criteria. Winds will improve later tonight, although seas will take a bit longer to subside. Advisories should be able to come down by daybreak. Saturday through Wednesday: High confidence through the period. High pressure will slowly build into the area this weekend behind a departing cold front. Small Craft Advisory conditions are possible Saturday night into Sunday as winds surge from building high pressure. Otherwise, no significant concerns through next Wednesday. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...Small Craft Advisory until 6 AM EST Saturday for AMZ350-374. && $$ NEAR TERM...NED SHORT TERM...RJB LONG TERM...JRL AVIATION...NED/RJB MARINE...ETM/RJB