Marine Weather and Tide Forecast for Talahi Island, GA

KEY MESSAGES
- 1) A cold front will bring low end rain chances today, followed by a brief cooldown early this week.

- 2) Minor coastal flooding possible along the South Carolina coast again this evening.

DISCUSSION
KEY MESSAGE 1: A cold front will bring low end rain chances today, followed by a brief cooldown early this week.

This morning, regional radar composite and sfc observations indicated that the cold front was located over the Southern Appalachians and northern GA, pushing east. Given radar trends and high resolution guidance, the front is timed to reach SE GA/SC just after daybreak this morning. NAM12 indicates that H85 temperatures ahead of the front is forecast to range between 10-15C at 12Z, cooling to 6-8C by 21Z. The moderate CAA should result in temperatures peaking in the mid 70s inland to the low to mid 80s along the coast during the mid-day hours. Temperatures should gradually cool through the rest of the day.

Unfortunately, the showers behind the front will gradually weaken in the downslope flow within the lee of the Appalachians today. In fact, REFS indicates that the line will totally dissipate upstream of the forecast area. Recent runs of the HRRR indicates only a few cells with dBZ cores around 30 this afternoon. Forecast soundings indicates a very dry layer below H7 with little to no SBCAPE. This forecast will continue with 20 to 30 PoPs, generally along and north of the Savannah River. Little to no measurable rainfall is expected today.

Temperatures will cool tonight into Monday morning. Guidance indicates low temperatures Monday morning may range from the mid 40s inland to the low to mid 50s along the coast. High temperatures on Monday should favor values in the upper 70s to near 80, which is near the normal high temperature. A secondary cold front may push across the area on Monday, with CAA and clear sky Monday night. Low temperatures on Tuesday should be comparable to Monday's values.
Temperatures will then warm back into the 80s by Wednesday. Each afternoon early this week will yield very low values of RH, ranging from the teens to 20s.

KEY MESSAGE 2: Minor coastal flooding possible along the South Carolina coast again this evening.

Elevated tidal ranges owing to the new moon (Friday) and perigee (today) will begin to slowly subside today. Tidal departures are likely to diminish as winds become northwest behind a cold front that will cross coastal areas this afternoon. However, departures potentially climb again later in the evening as the flow becomes more northeast. If the departure remains elevated enough, minor coastal flooding is possible once again with the 10:30 PM high tide for the South Carolina coast, but cold frontal timing and post- frontal wind strength will need to be monitored before the coastal flooding forecast comes in to better focus.

AVIATION /06Z SUNDAY THROUGH THURSDAY/
VFR conditions expected across the terminals through the 6Z TAF period. Southwest to west winds around 10 kts should continue through early this morning. A strong cold front is timed to sweep across terminals around 15z this morning, with winds veering from the northwest with gusts around 20kts. This will generally be a dry cold front, however, a shower or two may pass close to KCHS and KJZI. These showers will be highlighted with a mention of VCSH from 18-23Z. By early this evening, winds will turn from the northeast and will remain between 8-10 kts through the remainder of the TAF period.

Extended Aviation Outlook: Dry high pressure keeps VFR conditions in place through much of the coming week.

MARINE
A strong cold front is expected to sweep across the marine zones this afternoon. Winds will veer from the NNE by this evening, with gusts between 20-25 kts outside the Charleston Harbor. Seas are forecast to build from 2-4 ft today to 3-7 ft by dawn Monday. A Small Craft Advisory is in effect for the outer GA waters from this evening until Monday afternoon to highlight the gusty winds and building wave heights.

High pressure moves overhead Monday, with the gradient rapidly weakening and light winds prevailing outside of the sea breeze corridor by Monday afternoon. Secondary high pressure across the Mid- Atlantic will ridge down the coast, bringing a brief period of moderate to breeze NE winds Tuesday, with winds potentially approaching SCA criteria. This high then builds overhead Wednesday, with light winds again prevailing mid-to-late week.

Rip Currents: A Moderate Risk of rip currents remains in place for all beaches today due to the combination of 2-3 ft breakers and elevated astronomical influences associated with lunar perigee/new moon. In the wake of strong cold front today, high pressure will surge across the region tonight, resulting in gusty northeast winds tonight through Monday morning along the coast. These winds should generate a strong longshore current into Monday. Given the longshore current combined with breakers around 3 ft and lingering elevated tide cycles, a moderate risk will remain for all beaches on Monday, possibly into Tuesday.

CHS WATCHES/WARNINGS/ADVISORIES
GA...None.
SC...None.
MARINE...Small Craft Advisory from 7 PM this evening to 5 PM EDT Monday for AMZ384.