Marine Weather and Tide Forecast for Charleston, SC

NEAR TERM /THROUGH TONIGHT/
Through Sunset: No hazardous weather is expected.

Tonight: Southwest flow in the mid-levels will prevail while a trough moves over the Great Lakes Region. At the surface, High pressure to our northwest this evening will shift away.
Meanwhile, a trough just offshore will strengthen and move closer to the coast. Additionally, a cold front will approach from the west overnight. Though, this front will not reach our area overnight. Moisture will increase, with PWATs approaching 1" late tonight. But even with the increased moisture, the NBM keeps our land areas dry. However, clouds will gradually increase. Lows will range from the middle 30s far inland, moderating to near 50 degrees at/near the beaches.

SHORT TERM /SUNDAY THROUGH TUESDAY/
Sunday: As the weak coastal trough traversing across the Great Lakes region mixes out ahead of an approaching cold front, southwesterly flow aloft will yield PWAT values between 1 to 1.5" by the afternoon. Additionally, temperatures should be able to return to the upper 60s to low 70s in the WAA regime.
Isentropic lift may result in some weak showers in the morning, however the chance of this remains quite low. Expect cloud cover to increase through the evening and into the overnight, with lows dropping into low 40s inland and the mid 40s to low 50s near the coastline.

Monday and Tuesday: As the front pushes offshore Monday morning, expect surface high pressure to build into the region from the north throughout the day. This feature will produce temperatures back down into the mid 50s to mid 60s, with the warmest temps. across southeast Georgia on Monday. Some drier air is expected to filter in behind the front, however this will only last momentarily as the next system approaches. A surface low should develop across the Gulf and move rather quickly towards the region from the southwest late Monday evening into Tuesday. This will yield a surge of moisture and PWATs will ramp up to 1.5-1.75" overnight. Simultaneously, chances of rainfall will also increase with the greatest chance on Tuesday morning into the early afternoon as the low passes through the region.
However, despite PWAT values approaching the 90th percentile, rainfall amounts look to remain around 0.50 to 1.0 inches, with the highest across the interior counties of SOuth Carolina. This will likely add some relief to the ongoing drought conditions across the region.

LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/
After the surface low passes through the region, chances for rainfall dwindle with surface high pressure building into the region behind the system and ensemble guidance suggests the upper-lvl flow becomes more zonal. This pattern will produce temperatures near normal throughout the period. Expect surface high pressure to move offshore rather quickly as another system approaches the region from the southwest. However, model consensus remains rather poor on the timing of this system for the the end of the week.

AVIATION /18Z SATURDAY THROUGH THURSDAY/
18Z TAFs: VFR.

Extended Aviation Outlook: Low-lvl moisture will increase ahead of an approaching surface low, this will likely yield flight restrictions (in terms of low ceilings) as early as Sunday evening. However, the higher chance of flight restrictions will occur on late Monday evening into Tuesday after as the aforementioned low passes through the region. This system will likely produce low ceilings and reduced vsbys.

MARINE
Through Sunset: No hazardous weather is expected.

Tonight: High pressure to our northwest this evening will shift away, while a surface trough just offshore strengthens and moves closer to the coast. Additionally, a cold front will approach from the west overnight. This synoptic setup will bring sustained NE winds 15-20 kt this evening, then veering overnight, and easing to around 10 kt by daybreak Sunday. Seas 4-5 ft this evening should subside to 3-4 ft overnight.

Sunday through Wednesday: Expect weak southeasterly winds to spin towards the northeast by Monday as a cold front passes through the local waters on Monday morning. These northeasterly winds will likely increase throughout Monday as a surface low approaches the region from the southwest, with speeds 10 to 15 kts and gusts up to 20 kts. It's also possible to see some 6 footers in the Charleston nearshore waters as early as Monday evening. As the surface low passes through the region on Tuesday, winds will out of the veer the southwest and increase a touch, but remain sub-advisory in the forecast. However, a reinforcing shot of south-southeasterly swell mixes into the waters on Tuesday and seas increase to 5 to 7 ft in the South Carolina nearshore and 6 to 8 ft in the outer Georgia waters on Tuesday afternoon. Therefore, Small Craft Advisories will likely be needed on Tuesday afternoon into the overnight. Afterwards, the swell looks to ease back as high pressure returns to the Atlantic waters on Wednesday and conditions rapidly improve.

CHS WATCHES/WARNINGS/ADVISORIES
GA...None.
SC...None.
MARINE...None.