Marine Weather and Tide Forecast for Rockville, SC

NEAR TERM /UNTIL 6 AM THIS MORNING/
A quiet and seasonably warm night is in progress across Southeast South Carolina and Southeast Georgia. Dry conditions will prevail for most areas through the night, although a few hours may approach the far western areas around daybreak. Lows from the lower 60s inland to around 70 at the beaches look on track. No major changes were made for the midnight update.

SHORT TERM /6 AM THIS MORNING THROUGH MONDAY/
Saturday: Large-scale ridging across the United States will persist, as a shortwave situates itself overhead and slowly moves east and eventually off the eastern seaboard overnight. Heights will increase throughout the day as the aforementioned ridging nudges closer. With the shortwave departure overhead, there is some signaling of instability firing up in the afternoon. Latest HRRR suggests CAPE values ~1500 J/kg in the afternoon with 0-3 SRH values ~100-150 m^2/m^2 (some pockets of 200m^2/s^2). This combined with a potential afternoon seabreeze could stir up some convection (especially over interior southeastern South Carolina). PoPs were increased to 40-60% in the afternoon for the Charleston Tri-County due to it being a more favorable environment than the rest of the region. However, rainfall amounts remain low, most areas will only see 0.05 to 0.10 inches with regions more inland seeing 0.15 inches at best. Highs will be in the mid to upper 80s in southeastern South Carolina and upper 80s to low 90s in southeastern Georgia with cooler temperatures closer to the coastline. Overnight lows will drop into the low to mid 60s and upper 60/low 70s closer to the coastline.

Sunday: As the aforementioned shortwave shifts off the Northeast coast in the morning, an associated cold front passes through to the south of the region. Some models are indicating that the front will stall across southern Georgia to near the Florida state line in the evening as a cyclonic flow persists aloft. It is possible to see some showers and thunderstorms with this frontal passage as the afternoon seabreeze could force some convection develop. Behind the front, high pressure situated over the Midwest begins to build into the region. Left PoPs in the 20-30% for southeastern Georgia, might need to increase later on but will wait how things change in the next day or so. Highs will warm into the low to mid 80s across southeastern South Carolina and upper 80s to low 90s across southeastern Georgia with cooler temperatures closer to the coastline. A bit cooler on Sunday night partially due to the high pressure building in behind the front and clearing out the skies allowing good radiational cooling to occur. Lows will dip into the upper 50s to low 60s with it being a tad warmer along the beaches.

Monday: A tropical ridge centered over Mexico will begin to shift eastward over the Gulf and Southeast CONUS. It doesn't look like a very favorable environment for any showers and/or thunderstorms to pop up, thus PoPs were lowered. Highs will climb into upper 70s to low 80s with cooler temperatures along the coastline.

LONG TERM /MONDAY NIGHT THROUGH FRIDAY/
As an Atlantic high pressure nudges closer, subtropical ridging will dominate aloft. Most of the extended period will remain quite until Friday afternoon when the next chance for showers is expected.
Temperatures will hold at or slightly above normal levels for late April. Resultant sea breeze influences are likely each afternoon/evening.

AVIATION /04Z SATURDAY THROUGH WEDNESDAY/
26/06z TAF Discussion: KCHS/KJZI/KSAV: Some shallow ground fog could impact all terminals through daybreak, but most likely at KJZI. A TEMPO group for 4SM MIFG was included 09-12z at KJZI to account for this. Quiet conditions will prevail this morning with VFR conditions. Scattered showers/tstms are expected to develop near KCHS and KJZI later this afternoon during peak instability.
VCTS was included 19-22z at KCHS and 20-23z at KJZI for now as timing is a bit uncertain. The need for anything more will be reevaluated at 12z. For KSAV, activity will be much more isolated and probabilities are too low to include a mention of tstms just yet.

Extended Aviation: There is a possibility of fog and/or low stratus Sunday morning Gusty winds are possible each afternoon with the passage of the resultant sea breeze.

MARINE
Tonight:The local waters will remain situated on the western side of a huge Atlantic high. The gradient will stay fairly lax, as SE and S winds around 10 kt early on, veer around to the S and SW at similar speeds due to land breeze influences overnight.
The wave spectrum will be mainly due to swells, and will average 2-4 feet, highest on the outer Georgia waters.

Saturday through Wednesday: Expect southerly winds to persist Saturday before turning northerly with the passage of the cold front on Sunday. On Monday, northeasterly winds will gradually veer easterly, and then southerly Tuesday and Wednesday. Marine conditions look to remain calm, however gust to 15 to 20 kt with the afternoon/evening sea breeze each day. Seas will generally be from 2 to 3 ft, except build 3 to 5 ft on Monday and Tuesday due to post FROPA (especially for the outer Georgia waters).

Rip Currents: A 2 ft, 9 sec easterly swell will persist into Saturday. These conditions combined with enhanced winds along the land/sea interface with the sea breeze and the approaching new moon will support a high risk for rip currents along the Charleston County and Beaufort County beaches with a moderate risk for southeast Georgia beaches on Saturday.

The risk deescalates some on Sunday, expect low risk for rip currents along Charleston County and Beaufort County beaches with a moderate risk for southeast Georgia beaches.

TIDES/COASTAL FLOODING
Minor to moderate coastal flooding is possible with the evening high tides due to the elevated tides from the approaching new moon and perigee. For the Charleston Harbor gage, the astronomical tides rise above 6.5 ft MLLW with the evening tides Saturday through Wednesday. With the approaching surface high pressure Sunday and Monday, northeasterly to easterly surface flow may cause the waters to rise into minor flood stage (7.0 ft MLLW) with the evening high tides with a possibility for moderate flooding (7.5 ft MLLW) for the Sunday evening high tide. For the Fort Pulaski gage, minor flooding (9.5 ft MLLW)
is possible with the Sunday evening high tide. Coastal Flood Advisories will be needed for portions of the coast.

CHS WATCHES/WARNINGS/ADVISORIES
GA...None.
SC...High Risk for Rip Currents from 8 AM EDT this morning through this evening for SCZ048>051.
MARINE...None.