Hilton Head Island, SC Weather

What Has Changed

Aviation section updated for 00Z TAFs, but no significant changes to forecast thinking.

Key Messages

- 1) A significant, multi-day coastal flooding event will continue this week.

- 2) Strong northeast flow through early week will result in several hazards including rip currents, high surf, and beach erosion.

- 3) Dry conditions and below normal temperatures will continue through early next week before gradually warming up by the end of the week.

Discussion

KEY MESSAGE 1: A significant, multi-day coastal flooding event will continue this week.

Astronomical tides will continue to rise into early this week due to the upcoming full moon (10/26) and the lunar perigee (10/28). Large tidal departures are ongoing, and with an extended period of strong northeast flow this weekend and into next week, departures will increase in magnitude. The combination of the highest astronomical tides of the year and persistent strong northeast flow will result in a multi-day moderate to major coastal flooding event for the entire southeast GA/SC coast.

This Evening: A Coastal Flood Advisory remains in effect for Charleston and Coastal Colleton counties from 6 to 10 PM this evening. Tide levels at the Charleston Harbor are forecast to reach 7.2-7.4 ft MLLW. The current forecast keeps Fort Pulaski just shy of minor flood levels, 9.4 ft MLLW. Therefore, a Coastal Flood Advisory is not planned for the rest of the coastline at this juncture.

Monday Morning: The highest tide level of the event is forecast to occur around 8 AM, with 7.9-8.1 ft MLLW forecast at the Charleston Harbor and 10.0-10.2 ft MLLW at Fort Pulaski. A Coastal Flood Watch is in effect for Charleston and Coastal Colleton Counties, as this tide is forecast to reach major flood levels. Elsewhere along the coast a Coastal Flood Advisory will likely be required, including Tidal Berkeley.

Rest of This Week: Coastal flooding is forecast to occur with the Tuesday, and Wednesday morning high tide cycles, with minor flooding possible through the end of the week. During these cycles, it is possible that the Charleston Harbor could exceed major flood stage. Additionally, Fort Pulaski could exceed moderate flood stage (10.0 ft MLLW). Winds will slightly relax heading into this week, leading to lowering tidal departures. Coastal Flood Advisories will be needed, and Coastal Flood Watches/Warnings are not out of the question for for Charleston and Coastal Colleton counties through Wednesday.

KEY MESSAGE 2: Strong northeast flow through early week will result in several hazards including rip currents, high surf, and beach erosion.

Aviation

VFR Conditions prevail. A pinched gradient will keep northeast winds elevated. Gusts will be infrequent overnight, but 15-20 kt gusts will return shortly after sunrise and persist through the day on Monday.

Extended Aviation Outlook: VFR conditions are expected at CHS/JZI/SAV through late week. Although gusty north-northeast winds (15-20 kt) could occur at all terminals during afternoon hours.