Hilton Head, SC Weather

What Has Changed

All sections updated.

Key Messages

- 1) Dry conditions and below normal temperatures will continue into early next week.

- 2) A significant multi-day coastal flooding event is expected this weekend through at least the middle of next week.

- 3) Strong northeast flow this weekend and into early next week will result in several coastal hazards including rip currents, high surf, and beach erosion.

Discussion

KEY MESSAGE 1: Dry conditions and below normal temperatures will continue into early next week.

Rest of Today and Tonight: Strong high pressure centered to the north of the Great Lakes will dominate through the remainder of today and through tonight. A strong mid-level shortwave trough was analyzed on this morning's 12Z 500mb analysis from the SPC. This feature will help keep temperatures slightly cooler than yesterday, with highs generally in the low to mid 70s away from the beaches. The pressure gradient will begin to quickly tighten tonight as low pressure begins to organize east of the Southern Bahamas and the strong high pressure wedges south across the Carolinas and Georgia. An uptick in winds is expected tonight, with breezy conditions developing at the beaches and around the Santee-Cooper lakes. Despite clear skies, the elevated winds will yield a warmer night in comparison to previous nights this week with lows ranging from the upper 40/lower 50s inland to around 60 at the beaches. Some mid 40s could occur, mainly in the Jenkins- Allendale corridor where winds will be the lightest.

Saturday through Thursday: Surface high pressure will extend across the region through late next week. Over the weekend, the high will strengthen inland while a coastal trough develops offshore. The air mass will remain quite dry. The pattern will support a rain- free forecast through at least early next week. Despite plenty of sunshine, temperatures will lean on the cooler side of normal, owing to the persistent NE flow. Highs will top out in the lower to mid 70s for the weekend and early next week. Low temperatures will fall into the 40s across many interior locations.

KEY MESSAGE 2: A significant multi-day coastal flooding event is expected this weekend through at least the middle of next week.

Astronomical tides will continue to rise through the weekend and into next week due to the upcoming full moon (10/26) and the lunar perigee (10/28). Large tidal departures are already ongoing, and with an extended period of strong northeast flow this weekend and into next week, these 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.

Upcoming evening high tide (~6:45 pm): Minor coastal flooding will likely occur at Charleston with the evening high tide cycle. The astronomical high tide is 5.79 ft MLLW and we are currently running a 1.2-1.3 ft departure as we head into the preceding low tide. We currently expect high tide to peak in the 7.0-7.2 ft MLLW range, and a Coastal Flood Advisory is in effect for Charleston and coastal Colleton counties. There are no coastal flooding concerns at Fort Pulaski.

Aviation

VFR through the 18Z TAF period. Gusty NE winds will develop at KCHS/KJZI/KSAV on Saturday, gusting upwards of 25 knots.

Extended Aviation Outlook: Breezy northerly winds anticipated at CHS/JZI/SAV terminals through Monday morning. Gusts could reach 25- 30 kt, especially during the afternoon hours Saturday and Sunday. Otherwise, VFR conditions are expected at all terminals through Tuesday.