NEAR TERM /UNTIL 6 AM MONDAY MORNING/
The National Hurricane Center is issuing advisories on Potential Tropical Cyclone Eight located off the Southeast Coastline. A Tropical Storm Warning remains in effect for Charleston and Berkeley Counties.

Tonight: A broad swath of showers will continue to nudge closer to the local area from the north/northeast, but will struggle to make much progress south across the Tri-County Area overnight due to dry air (currently depicted on water vapor imagery) wrapping along the southern edge of Potential Tropical Cyclone Eight tracking toward the Carolina Coast. Scattered to numerous showers are possible across far northern Charleston and Berkeley Counties this evening, with perhaps widespread precip coverage near the immediate coast for the next few hours. Expect the focus of precip to remain across the same northern areas of Charleston and Berkeley Counties through daybreak as Potential Tropical Cyclone Eight approaches the coast late, producing upwards to 1/2 to 1 inch rainfall accumulation (highest near the coast).

Outside precip, gusty northeast winds will gradually turn north to north-northwest overnight between high pressure inland and Potential Tropical Cyclone Eight approaching from offshore. Gusts across the Charleston Tri-County will generally range between 20 and 30 mph.
However, gusts could be slightly stronger possible on overpasses and higher bridges. Between cloud cover, showers and gusty winds, overnight lows will likely only dip into the upper 60s inland to lower 70s near the coast.

SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/
Monday: The biggest forecast concern for this period remains to be the developing low center, currently Potential Tropical Cyclone 8, just offshore in the Atlantic waters. Using the track from NHC, the system is expected to make landfall somewhere between McClellanville and Georgetown, SC Monday afternoon. It should be noted that there is still a fair amount of uncertainty in the track timing and location. Regardless of whether or not this system becomes tropical in nature, the expected impacts have not changed. Still expect the best threat for tropical storm force winds/wind gusts of 40-50 mph to be over the Marine waters off of the Charleston County coast.
Some tropical storm force wind gusts could also reach the immediate Charleston County coast. The heaviest amounts of 1-2 inches, with locally higher amounts, will be possible over extreme northern Charleston and Berkeley counties, closer to the Santee River. Away from the coast, winds will be breezy, generally 10-20 mph with some gusts to near 30 mph. High temperatures around 80 over the Charleston Tri-county region and lower 80s rest of the region. By Monday night, using the current NHC track forecast, the cyclone should be inland, north of the Santee River in SC. Rainfall chances are expected to decrease from south to north, with chance PoPs mainly over the northern Charleston Tri-county, then below mention after midnight. Lows 65 to 70.

Tuesday and Wednesday: Although there remains uncertainty in the details of where the remnants of PTC8 will be located, global models show the area to be on the southern periphery of under a large, closed upper low with the remnant PTC8 circulation somewhere in the mountain region of the Mid Atlantic. Despite the upper trough and presence of deep layer moisture, guidance PoPs continue to be 20% or less for Tuesday and 20-35% for Wednesday. Expect any convection to be diurnally driven, helped by afternoon sea breeze. Highs in the lower to mid 80s Tuesday, and mid to upper 80s by Wednesday. Lows generally mid to upper 60s away from the coast, and around 70s to the lower 70s near the coast.

LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/
Forecast uncertainty is higher than normal for this period. In general, models indicate the closed upper low over the mid Atlantic, will open up/weaken and move southward as upper ridging tries to develop from the Great Lakes, southwest to the lower MS Valley.
Higher values of deep layer moisture within the center of the upper closed low may move southward into the area, especially by Friday and Saturday. Also, the upper low moves southward and weakens, a surface ridge may strengthen over New England and the Mid Atlantic, which allows low level northeast winds to form over the region. Have kept slight chance to low end chance PoPs for this period, centered around the afternoon heating. Highs near to slightly above normal in the mid to upper 80s through Friday, then possibly cooling to into the lower 80s Saturday.

AVIATION /01Z MONDAY THROUGH FRIDAY/
Periods of MVFR cigs are expected at CHS/JZI/SAV terminals tonight through 19-20Z Monday while Potential Tropical Cyclone approaches the Carolina Coast. There is a potential for lower cigs/vsbys at CHS/JZI with any rain/showers associated with the system passing nearby. Northeast winds will also gradually turn northwest after daybreak Monday at CHS/JZI, but remain gusty with speeds up to 20-25 kt at times. Further south, winds will remain around 10 kt or less at SAV. VFR conditions should then prevail at terminals heading into evening hours Monday.

Extended Aviation Outlook: Monday night: MVFR CIGs and gusty winds expected for KJZI and KCHS with periods of showers on the back-side of the Potential TC8. MVFR conditions for KSAV, but less breezy wind and lower chances for any showers.

Tuesday through Thursday: return to more VFR condition, with isolated mainly afternoon showers and possibly a thunderstorm, which could bring brief flight restrictions.

MARINE
Tonight: Conditions across the local waters will continue to deteriorate as the area remains situated in the tight gradient between the inland high and Potential Tropical Cyclone Eight. A Tropical Storm Warning remains in effect for the Charleston County nearshore waters as well as the Charleston Harbor.
Elsewhere, Small Craft Advisories remain in effect through the the night with northeast winds between 20-30 kt being common along with a few gusts up to 35 kt at times. Seas will be highest in the Charleston County waters and the outer Georgia waters, where seas up to around 10 feet will be possible through tonight. Elsewhere, seas will mostly be in the 5-8 ft range.

Monday and Monday night: Main forecast concerns continues to be the progression of now Potential Tropical Cyclone 8. Despite whether or not this system becomes tropical in nature, we are not expecting any change in our previous thinking of winds/seas. Tropical storm force wind gusts will continue over AMZ350 and near the mouth of Charleston Harbor, possibly through Monday afternoon. High end SCA conditions the rest of the waters. By Monday night, the NHC track takes the storm inland, which should begin the gradual decrease in winds and seas. Winds may fall below highlights by Monday night all waters, but seas could stay AOB 6 feet beyond 20 nm offshore through Tuesday morning.

Later Tuesday through Friday: No highlights expected with generally south-southwest winds of 15 kts or less and seas 2 to 4 feet, highest beyond 20 nm. A surface front may move into the waters Friday, which could switch winds to north-northeast and increase to 10-15 kts, but uncertainty moderate to high for this portion of the forecast.

Rip Currents: The combination of strong northerly winds and increasing swell from Potential Tropical Cyclone Eight just offshore will result in a High Risk of rip currents at all beaches through the day Monday.

High Surf: Breaking waves are expected to peak around 3-5 ft tonight at Southeast South Carolina beaches. A High Surf Advisory remains in effect there. Georgia beaches should see breakers shy of 5 feet, peaking around 3-4 ft, which does not meet the criteria for a High Surf Advisory. Due to a combination of elevated water levels and powerful breaking waves, significant beach erosion is likely, especially along east and northeast facing beaches.

TIDES/COASTAL FLOODING
Charleston and Coastal Colleton Counties: The tide forecast becomes a bit more uncertain Monday as predicted tide levels peak while winds turn more north/north-northwesterly with time as Potential Tropical Cyclone Eight moves closer to the coast, then north of the region by late Monday afternoon. For now, minor coastal flooding is possible during the Monday morning and evening high tide cycles, but further adjustments are likely.
Later this week, the risk for at least minor flooding will continue as elevated tides persist.

Beaufort County, SC, south to McIntosh County, GA: The tide forecast becomes less clear on Monday as water levels will be fighting northerly winds. For now, levels were kept just below minor flood levels Monday. Waters levels could be close to minor flood levels later this week as onshore winds return, but should largely remain below.

CHS WATCHES/WARNINGS/ADVISORIES
GA...High Risk for Rip Currents through Monday evening for GAZ117-119- 139-141.
SC...Tropical Storm Warning for SCZ045-050-052.
High Risk for Rip Currents through Monday evening for SCZ048>051.
High Surf Advisory until 8 AM EDT Monday for SCZ048>051.
MARINE...Tropical Storm Warning for AMZ330-350.
Small Craft Advisory until 11 PM EDT Monday for AMZ352.
Small Craft Advisory until 5 PM EDT Monday for AMZ354.
Small Craft Advisory until 1 PM EDT Tuesday for AMZ374.