752 FXUS62 KCHS 020559 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 1259 AM EST Sat Feb 2 2019 .SYNOPSIS... High pressure will prevail to the north tonight. Weak upper level disturbances are forecasted to affect the area this weekend. High pressure will then build across the region and persist through late next week. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... Early this morning: Much of the area of very light precipitation just to the south has dissipated, but there are still areas of showers along and south of I-16. So far, showers haven't made much northward progress. This is primarily because the best moisture still resides across the southern third of the forecast area where precipitable water values are greater than an inch. Further north, values are more in the 0.6-0.8 inch range. Through sunrise, thinking remains that the best chance for rain will exist roughly along and south of I-16 which will be much closer to the approaching mid-level shortwave. Made adjustments to rain chances but no overly significant alterations were needed. && .SHORT TERM /6 AM THIS MORNING THROUGH MONDAY/... Saturday: A mid-level short-wave with some vorticity embedded within it will move over our area from the morning into the afternoon. A second, stronger short-wave will approach from the west in the evening, reaching our area by daybreak Sunday. At the surface, high pressure over the Mid-Atlantic states in the morning will retreat while a coastal trough strengthens over/along the FL east coast. The bulk of the energy with this feature is forecasted to remain just offshore. However, the feature itself should brush our coastline into the afternoon hours, moving to the northeast along the coastline into the overnight hours. The bulk of the moisture will remain far offshore. Though, PWATs across our area will generally be above 1". Factoring all these variables, we have likely POPs brushing along the coastal counties during the day, tapering as one heads inland. The QPF reflects this. Though, rainfall amounts won't be substantial. Highs will be a few degrees above normal, while lows remain very mild. One thing to note is if the position of the trough moves further inland than expected, then a substantial change to the POPS and QPF would be needed. Sunday: A mid-level short wave will be over the Southeast in the morning. This wave is forecasted to slowly move eastward during the day while amplifying. It is forecasted to develop into a low as it moves offshore overnight. At the surface, a coastal trough will generally be brushing along northern portions of our area in the morning. This feature will move away during the day, accelerating to the northeast into the night. At the same time, high pressure initially over the Mid-Atlantic states will gradually build southwards into the evening and overnight hours. The highest moisture will be located near Charleston in the morning, gradually lowering into the day and especially at night. POPs are generally in the chance category during the day with only a few hundredths of QPF expected. Conditions are expected to dry out overnight with gradually clearing. Highs will once again be a few degrees above normal. Lows will be above normal too. Though, not as warm as the previous night due to some clearing. Monday: The mid-levels will consist of a strengthening low off the Southeast coast. This low will be pushed away by building heights within semi-zonal flow over our area. At the surface, high pressure will be over the Southeast. In the Atlantic will be a departing low/trough. To the west will be a distant, approaching front. The high will dominate the forecast, bringing dry conditions with some clouds. The airmass does start to moderate, with highs rising about ten degrees above normal. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... A drier and warmer pattern is anticipated heading through at least the middle of next week as sfc high pressure settles over the Southeast under a ridge of high pressure building aloft. In general, afternoon temps should peak into the low 70s Tuesday, then mid 70s Wednesday and Thursday well ahead of a front approaching northern areas next weekend. Overnight lows will also trend warmer a few degrees each night, from the upper 40s/lower 50s Monday night to mid/upper 50s by Wednesday night. Although a few showers are possible across inland areas mid week, the best chances of precip appear to be next weekend should a front shift into the region. There is also a low threat of sea fog moving onshore into the immediate coastal areas mid to late week as light southerly winds and sfc dewpts approach 60 degrees over cooler shelf waters. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... VFR conditions should prevail through sunrise. Then the chance for MVFR ceilings increases through the day as an area of low pressure develops offshore. Have started MVFR ceilings at KSAV at 13z and also brought in some showers by around midday. Guidance continues to suggest for KSAV that IFR ceilings will start in the afternoon. Have delayed it until almost sunset, bringing IFR into the terminal at 21z. Once IFR ceilings settle in, conditions could remain IFR through the rest of the forecast period. Ceilings will be slower to arrive at KCHS, and most of the forecast period is VFR. Brought in MVFR ceilings at 02z Sunday. Extended Aviation Outlook: Weak upper level disturbances along with a coastal trough could bring periods of flight restrictions into Sunday. VFR will prevail Monday through Wednesday. && .MARINE... NE flow will gradually strengthen overnight as the coastal trough strengthens off the FL/GA coast. Weak upper level disturbances are forecasted to move over the region this weekend. This will cause a coastal trough initially along the east coast of FL to move northeastward, passing along our coast Saturday. The trough should continue it's movement to the northeast and away from our area on Sunday. Winds are expected to be at their strongest Saturday, sustained at perhaps no more than 15 kt across the waters. Winds should then ease a few kt Sunday. Inland high pressure will build on Monday, causing winds to veer with speeds at or below 10 kt. Seas will generally range between 2-4 ft into early next week, but we could see waves as high as 5 ft in the offshore GA waters late Sunday. High pressure should then extend across the waters by Tuesday, then persist into the middle of next week. Winds and seas will remain well below Small Craft Advisory levels during the transition, but light southerly winds should develop heading into mid week. These winds along with dewpt temps approaching 60 degrees, could become more favorable for sea fog over cooler shelf waters mid week. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...BSH SHORT TERM...MS LONG TERM...DPB AVIATION...BSH/MS MARINE...JRL/MS