textproduct: Charleston

WHAT HAS CHANGED

All sections have been updated.

KEY MESSAGES

- 1) A multi-day coastal flooding event will continue this week. - 2) Enhanced northeast flow will lead to a high risk for rip currents into mid-week along South Carolina and Georgia beaches. - 3) Dry and warming conditions will continue through the week before rain chances increase late weekend.

DISCUSSION

Astronomical tides will continue to rise into early this week due to today's full moon (10/26) and the lunar perigee (10/28). Northeasterly flow at the surface have driven an increase in tidal departures. The combination of the highest astronomical tides of the year and persistent strong northeast flow will result in threat of at least minor coastal flooding through the remainder of this week.

This Evening: North-northeast flow will continue today, but is expected to gradually weaken into evening hours. Departures should remain smaller as a result, and should support total water levels that fall just short minor flooding. Therefore, a Coastal Flood Advisory is not planned for the Charleston/Coastal Colleton Coast for the evening high tide cycle. Coastal flooding is not expected across southern coastal SC and coastal GA areas during the evening high tide cycle as Fort Pulaski is also forecast to remain shy of minor flood stage.

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 moderate flood stage. Winds will slightly relax as the week progresses, leading to lowering tidal departures. Coastal Flood Advisories will likely be needed.

KEY MESSAGE 2: Enhanced northeast flow will lead to a high risk for rip currents into mid-week along South Carolina and Georgia beaches.

Rip Currents: Strong northeast winds, long-period swell and ongoing wave action will continue to support dangerous rip currents along all SC/GA beaches into mid week. A High Risk for rip currents is in place for all beaches this afternoon through Tuesday as a result, and should persist for all beaches again Wednesday. Conditions should start to improve mid-late week as long-period swell decreases and winds weaken beyond peak astronomical factors occurring earlier in the week.

KEY MESSAGE 3: Dry and warming conditions will continue through the week before rain chances increase late weekend.

A persistent synoptic pattern holds through late week, with upper lvl ridging over the northern Gulf Coast and Southeast United States and an upper lvl low lingering near the Bahamas. At the sfc, high pressure centered over the Northeast United States will continue to stretch south across the region, allowing a wedge to hold in place across the Carolinas into mid week. The wedge will show signs of weakening as the upper ridge begins to flatten and slide east during the second half of the week, and full days of sun support a modifying airmass. This will allow temps to warm a few degrees above normal during the week with afternoon highs in the mid 70s near the coast and upper 70s/around 80 inland. Strong radiational cooling nights under high pressure should allow temps to dip into the low/mid 40s inland to mid-upper 50s near the coast for the next couple nights, but will also trend warmer through the week.

The extended period of drier weather looks to come to an end late weekend as high pressure breaks down with the approach of a low pressure system passing across the Deep South and advancing eastward across the Southeast and/or Mid-Atlantic States late weekend. This should bring chances of showers and/or perhaps a few thunderstorms across South Carolina and Georgia heading into early next week.

AVIATION /18Z MONDAY THROUGH SATURDAY/

VFR Conditions are expected at CHS/JZI/SAV terminals through 18Z Tuesday. However, gusty north-northeast winds (up to 12-17 kt) are possible at all terminals this afternoon.

Extended Aviation Outlook: Breezy north-northeast winds are expected at KCHS/KJZI/KSAV daily through the week.

MARINE

This Afternoon and Tonight: An enhanced pressure gradient will persist between high pressure wedged inland/to the north and weak low pressure well offshore. Expect north-northeast winds gusting upwards to 25-30 kt to slowly decrease this afternoon with minor surging overnight while seas 5-8 ft nearshore and 9-12 ft offshore linger, but also slowly subside through tonight. Small Craft Advisories will remain in effect across all nearshore waters (outside the Charleston Harbor) and offshore GA waters through the night.

Tuesday through Saturday: Winds/seas will gradually trend lower heading into Tuesday, but a fairly enhanced gradient between inland high pressure and persistent low pressure centered well offshore will likely maintain elevated winds and seas through late week. Solid Small Craft Advisory level conditions are expected across offshore Georgia waters through late week for north-northeast winds gusting to 25-30 kt and seas up to 8-10 ft. Nearshore waters will also be experiencing Small Craft Advisory level conditions into late week with north-northeast winds gusting around 25 kt and seas 5-8 ft, but there are signs that the pressure gradient could weaken/relax across local waters later this week, resulting in Small Craft Advisories ending early weekend.

CHS WATCHES/WARNINGS/ADVISORIES

GA...High Risk for Rip Currents through Tuesday evening for GAZ217-219- 239-241. SC...High Risk for Rip Currents through Tuesday evening for SCZ148>151. MARINE...Small Craft Advisory until 8 PM EDT Friday for AMZ360-362. Small Craft Advisory until 2 AM EDT Saturday for AMZ364. Small Craft Advisory until 8 AM EDT Saturday for AMZ384.