648 FXUS62 KCHS 032010 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 310 PM EST Sun Feb 3 2019 .SYNOPSIS... Low pressure offshore will move away from our area tonight. High pressure will then build across the region Monday and persist for most of the week. A cold front is expected to move through the region towards the end of the week. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... Patchy light rain or drizzle will traverse mainly inland SC through late afternoon as the main shortwave moves through. Wrap around moisture associated with the deepening surface low off the Charleston County coast will maintain extensive low clouds over the area into early evening, after which skies should begin clearing out. A moderate gradient across southern SC should preclude fog, but with moist soils and light winds across interior southeast GA, we expect patchy to areas of fog to develop late tonight. Overnight lows will drop into the low to mid 40s. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... The mid-levels will consist of a strengthening low off the Southeast coast Monday morning. This low will be pushed away from our area Monday afternoon as heights build within semi- zonal flow. A weak ridge is forecasted to move over the Southeast from early Tuesday morning into the afternoon, then offshore Tuesday evening into the overnight. Heights will continue to build on Wednesday as strong high pressure in the Gulf of Mexico creeps closer to the Southeast. At the surface, the low/trough in the Atlantic will be departing Monday morning while high pressure persists over the Southeast. Models hint the center of the high should gradually drift southward into Tuesday, then drift back northward on Wednesday. As this is occurring, to the distant west will be an approaching front. But it will not reach our area because the high will block and shove it to our north. The end result will be dry conditions with a mix of sun and clouds for the entire short term. What will be very noticeable is the temperatures. A combination of rising heights, warming 850 mb temperatures, and a favorable surface wind direction will allow temperatures to rise each day. Highs on Monday could be about 10 degrees above normal while Highs on Tuesday and Wednesday could approach 15 degrees above normal, especially away from the beaches. Some records may eventually be at risk. There's also the potential for sea fog starting Tuesday. If it forms close to shore and moves onto the beaches, then it would cause visibility issues. But it's still too early to know for sure. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... A dry and warm pattern is expected during the second half of the week as sfc high pressure persists over the Southeast under a ridge of high pressure building aloft. Conditions should be warmest Thursday and Friday as the mid/upper ridge of high pressure becomes amplified across the Southeast ahead of a large trough of low pressure advancing over the Central United States toward the Midwest. In general, afternoon temps should peak in the mid/upper 70s each day, warmest away from the coast. Overnight lows will also be mild, ranging in the mid/upper 50s. There should also be a low threat of sea fog moving onshore and into immediate coastal areas as light southerly winds help push sfc dewpts to 60 degrees over cooler shelf waters during the second half of the week. The overall threat should come to an end this weekend as a cold front associated with the eastward advancing trough shifts through the Southeast United States. Isolated to scattered showers should accompany the front, before cooler high pressure wedges over the Mid-Atlantic and Southeast States late weekend into early next week. High temps should return to upper 50s/lower 60s post fropa. Lows should also be cooler post fropa, dipping into the mid/upper 40s inland to lower 50s along the immediate coast. && .AVIATION /20Z SUNDAY THROUGH FRIDAY/... KCHS: MVFR ceilings likely to continue through late evening, then VFR as drier air moves in. The best chance of fog overnight looks to be across southeast GA due to slightly stronger surface winds in southern SC. KSAV: IFR ceilings expected through early evening, then MVFR until late evening, followed by clearing. Better chances for fog across southeast GA late tonight where winds will diminish and soils are relatively moist. However, radiation fog typically develops farther southwest and gradually expands to the east, so we only added MVFR vsby a few hours before sunrise Monday. Later shifts will likely need to adjust as trends develop. Extended Aviation Outlook: VFR. && .MARINE... High pressure over the Southeast will bring tranquil conditions to the coastal waters for most of the week. Winds and seas are expected to remain below Small Craft Advisory levels. However, as winds turn southerly midweek, higher dewpoints will be advected over the cooler shelf waters, which could cause periods of sea fog to develop. The first opportunity for this is Tuesday afternoon and evening, followed by a brief reprieve as winds shift offshore. But southerly winds return on Wednesday, increasing the risk again. This risk will persist until a cold front moves through late in the week. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...JRL SHORT TERM...MS LONG TERM...DPB AVIATION...JRL/MS MARINE...JRL/MS