677 FXUS62 KCHS 060435 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 1235 AM EDT Tue Aug 6 2019 .SYNOPSIS... A stationary front will dissipate through tonight. A weak surface trough will then prevail inland while high pressure persists across the Atlantic mid to late week. A cold front will approach from the north this weekend. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... Skies will continue to clear from west-east. Convection over the eastern Midlands into the Pee Dee should remain to the north, but could still see an isolated shower/tstm pop across the Charleston Tri-County area as well as back closer to the I-16 corridor in Southeast Georgia through the night. Widespread fog/stratus appear unlikely, except across far interior Southeast Georgia where the lowest condensation pressure deficits are progged. Lowered overnight lows by a degree or so most areas per going trends. && .SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY/... Tuesday and Wednesday: A broad trough of low pressure will extend across much of the East Conus with its axis across or near the Southeast United States. At the sfc, a trough axis of low pressure will be placed across the Midlands while high pressure remains well offshore. Given the setup, conditions will represent those more typical of summertime with afternoon/evening showers and thunderstorms anticipated each day as a south/southwest sfc wind advects a fair amount of moisture (PWATs 1.75-2.00 inches) across the region while temps warm into the lower 90s away from the coast. Convection should initially develop along the seabreeze each day with sfc winds turning more south/southeast in its wake as it drifts inland before isolated to scattered showers/thunderstorms develop across most areas during peak diurnal heating. A few showers/thunderstorms developing upstream near the sfc trough could make a run toward inland areas late each day as subtle h5 shortwave activity rounds the base of the mid-lvl trough. Convection should remain sub-severe and wane early each night due to a lack shear and loss of diurnal heating. However, a stronger thunderstorm or two can not be ruled out. Overnight lows should range in the low/mid 70s each night, warmest near the coast. Thursday: Conditions could be noticeably drier as the broad trough of low pressure aloft flattens and downsloping winds develop across the Southeast. However, latest guidance suggests a quickly moving h5 shortwave shifting across the area, potentially resulting in showers and thunderstorms near the coast as it shifts over a swath of moisture near a pinned seabreeze. Given the setup, convection should be more isolated inland where the downsloping wind has a stronger hold across the area and mixing out of sfc dewpts is more likely to occur during maximum heating. Closer to the coast, coverage could be more scattered. The severe weather threat remains low, but a stronger thunderstorm or two can not be ruled out near the coast. High temps should be a degree or two warmer than the previous day, peaking in the low/mid 90s just inland from coastal locations. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... Mid-level troughing will be just off the East Coast Thursday night. It will slowly move offshore and weaken into Sunday. Meanwhile, high pressure will be building over the Plains States. At the surface, weak troughing will prevail inland while high pressure is over the Atlantic. A cold front is forecasted to approach our area from the north during the weekend. The forecast consists of the typical afternoon/evening showers/thunderstorms. High temperatures should be a few degrees above normal Friday. Low temperatures should be a few degrees above normal throughout the long term. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... KCHS: Mostly VFR. Monitoring for a risk for fog/stratus prior to daybreak. Latest data suggest conditions are too marginal for inclusion in the TAF at this time. Scattered showers/tstms are expected to develop across the region this afternoon. High resolution data suggest activity could impact the terminal in the 21-00z timeframe, but confidence for impacts in this coverage regime supports holding off on any mention at this time. KSAV: Webcams and surface observations show low stratus is trying to develop along the Savannah River. It is unclear how long this will last given no data shows stratus impacting this region. Any fog/stratus may be tempered as high clouds increase late. Will show prevailing SCT002 a TEMPO group for cigs near airport minimums through 08z with no mention of low cigs thereafter. Amendments may become necessary as trends become more apparent. Otherwise, VFR. High resolution data suggest activity could impact the terminal in closer to 00z, but confidence for impacts in this coverage regime supports holding off on any mention at this time. Extended Aviation Outlook: Brief flight restrictions are possible at both CHS and SAV terminals, mainly due to afternoon/evening showers or thunderstorms Tuesday through Thursday. Greater chances of flight restrictions are possible at both terminals due to showers and thunderstorms associated with an approaching cold front this weekend. && .MARINE... Tonight: A stationary front will linger over or near the local waters, which suppresses the mean Atlantic ridge across Florida. Outside of convection, S and SW winds will average no more than 10 or 15 kt, with seas no larger than 3 or 4 ft. But regarding the convection, activity will come off the Georgia coast early this evening and merge with additional activity from off the South Carolina coast during the mid evening to result in at least scattered to numerous showers and t-storms. Frequent cloud to water lightning and heavy rains reducing visibilities to near zero can also occur in some of the storms. Tuesday through Friday: Low pressure troughing will prevail inland while high pressure persists across the Atlantic through late week. The pattern will likely support conditions that remain below Small Craft Advisory levels through the period, but a slight tightening of the pressure gradient could result in a brief period of wind gusts near 25 kt Wednesday evening across northern South Carolina waters. Otherwise, expect mainly S to SW winds, veering a bit during the day and then backing at night. Seas should range between 2-4 ft. Additionally, scattered thunderstorms will occur for a good portion of the extended forecast period. Some of these storms could produce wind gusts in excess of 30-35 kt, reduced visibilities in heavy rain and frequent lightning strikes. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$