Marine Weather and Tide Forecast for North Charleston, SC

NEAR TERM /THROUGH TONIGHT/
Today: The majority of the CAMs guidance indicating that coverage of convection will be quite a bit less than past several days. This downward trend in convective coverage is likely due to the gradual increase mid/upper ridging from the southeast into the area as the trough well to the northwest decreases. Model guidance also points toward a later start to convection, with the seabreeze being the main activating feature at low levels. There may also be convective complex that moves well north of the area later this afternoon/early evening, which may put out boundaries into our northern area, especially Berkeley county. Have kept generally chance PoPs most of the area, with slightly higher PoPs closer to the coast with the seabreeze. Temperatures expected to be above normal, generally in the upper 80s to lower 90s. Given surface dewpoint temperatures remain in the lower 70s this afternoon, max heat indices could reach 100-103 in some areas.

Tonight: Any convection should be on the decrease after sunset.
Continued very mild with lows in the lower to mid 70s, and upper 70s to near 80 closer to the coast.

SHORT TERM /TUESDAY THROUGH THURSDAY/
Upper level ridging with a surface high pressure over the Atlantic continues throughout the short term, though the ridge begins to break down by late in the day Thursday as dry air is advected in from the south. Recent model runs have portrayed weak daytime upper level ridging occurring on Tuesday and Wednesday, which has decreased chances for daily showers and thunderstorms, albeit 20-40% chances still exist during the afternoon hours. 1500-2000 J/kg of CAPE will continue to lead to very isolated chances for severe weather, though the lack of upper level flow will keep such activity rather brief. On Thursday, a mid-level shortwave begins to move in from the west, which will start to flatten the ridge over the area as it builds westward over the CONUS southern great plains. Out ahead of an approaching cold front, another round of showers and thunderstorms are possible (20-30%), with the main question being whether or not the front reaches the area...most guidance indicates it stalls off to our northwest.

As the ridge strengthens, expect temperatures to continue increasing each day. NAEFs and ECMWF ensemble situational awareness tables (ESATs) continue to show the region remaining near/above the 90th percentile of climatology with respect to geopotential heights from 850mb up to 200 mb, though lower-level (700-850mb) temperatures remain below the 90th percentile of climatology. This will keep afternoon highs in the lower to mid 90s on each day, while those near the coast remain in the mid/upper 80s. Heat index values in the mid 90s to lower 100s are expected, possibly as high as mid to upper 100s if higher dewpoints in the upper 70s are realized.

LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/
The upper level ridge builds/shifts westward as the aforementioned weak trough moves into the northeast overnight into Friday.
Temperatures remain largely in the lower to mid 90s, with daily chances (20-40%) for showers and thunderstorms continuing into the weekend.

Behind the exiting upper level trough, deterministic and ensemble models continue to show a ridge building aloft as it moves eastwards towards the east coast. Highs each day will be in the low to mid 90s with heat indices topping out 100-105F.

AVIATION /12Z MONDAY THROUGH FRIDAY/
Today: VFR conditions to prevail through early afternoon.
Scattered showers and thunderstorms expected to develop by mid/late afternoon, which could produce brief flight restrictions at each terminal. Model guidance continues to trend lower for rain chances this afternoon, and start convection later than the past several days. Winds may gust briefly to 15-20 knots late morning into early afternoon at the atmosphere mixes. However, winds arethen expected to generally be SSW at 8-12 knots rest of day.

Tonight: Any onconvection should dissipate during the evening.
After 00z, expect conditions VFR all sites.

Extended Aviation Forecast: Brief flight restrictions are possible in showers and thunderstorms each day, mainly in the afternoon.

MARINE
Today and Tonight: No highlights are expected during the period.
However, winds may gust near 20 kts in Charleston Harbor and the nearshore regions of AMZ350 this afternoon with the seabreeze backing winds to more southerly near the coast in the afternoon.
Otherwise, generally south-southwest winds of 10-15 knots with seas 2 to 4 feet, highest seas beyond 10 or 15 nm offshore. A background long period swell from the east-southeast will still be present.

Tuesday through Saturday: Typical summertime conditions will prevail over the waters with high pressure centered offshore of the Southeast States. A broad, southerly wind regime can be expected with winds generally averaging 15 kt or less, except a bit higher along the land/sea interface and Charleston Harbor each afternoon with the sea breeze which could exceed 20 knots through Thursday.
Seas will remain 4 ft or less through the period.

Rip Currents: An easterly swell surge with 9 second swells continues today, and coupled with locally breezy conditions near the afternoon sea breeze will support a moderate rip current risk for all beaches today. Currently have low risk for rip currents expected for Tuesday as wave heights remain near 3 feet and swells below 6 seconds, though for the GA beaches there may be a period during the day where swells reach 8-9 seconds and could result in brief moderate risk for rip currents.

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