textproduct: Charleston

WHAT HAS CHANGED

All sections have been updated.

KEY MESSAGES

- 1) The coastal flood risk will linger into early next week.

- 2) Rising temperatures through Tuesday, remaining above normal next week.

DISCUSSION

KEY MESSAGE 1: The coastal flood risk will linger into early next week.

As a nor'easter churns offshore of the Eastern Seaboard, steady northerly flow will continue across the Lowcountry and southeast Georgia through the evening, before turning more west-northwesterly tonight. Even though this will create a less favorable environment for coastal flooding, the astro tide will still be elevated given the recent full moon. Thus, this will still result in minor (possible moderate) coastal flooding with each high tide cycle through early next week (esp. for the Charleston Harbor).

Charleston Harbor: With the ongoing environmental conditions, tidal levels could reach 7.4 ft MLLW in the Charleston Harbor for this evening's high tide (approx. at 834PM). Therefore, Coastal Flood Advisory has been issued from 7PM to 11PM this evening for Charleston and Colleton Counties. Saltwater inundation will be possible 2 to 3 hours before and after high tide, and will likely result in some roads becoming impassable.

Coastal flooding concerns will continue tomorrow (9/27) with the potential to reach moderate flood stage for Charleston and Colleton County with the morning high tide (~9AM). Thereafter, it's likely to see minor coastal flooding conditions through early next week for the Charleston Harbor.

Fort Pulaski: Tidal levels could reach 9.2 ft MLLW for this evening's high tide in Fort Pulaski (approx. at 841PM), thus this will not warrant a Coastal Flood Advisory for lower South Carolina and southeast Georgia. Additionally, guidance indicates tomorrow morning's high tide could see minor coastal flooding.

KEY MESSAGE 2: Rising temperatures through Tuesday, remaining above normal next week.

One last fall-like afternoon as the nor-easter continues to move into the northeast region, with rather tranquil conditions persisting for the next couple days over the southeast. Clear skies and light winds will set up another radiational cooling event tonight, with overnight lows in the lower to mid 50s for inland areas, and in the upper 50s to lower 60s for those along the coast.

Rising temperatures next week will be the main story, which will primarily be driven by the low-level (h925) thermal fields as ridging builds aloft into mid-week. Expect highs on Sunday primarily in the lower 80s, though areas south of the I-16 corridor will be in the mid 80s. Monday will be a touch warmer as the mid-80s build northwards and upper 80s become likely south of the I-16 corridor, with widespread mid 80s to lower 90s on Tuesday. Normally, high temperatures in the end of September are in the lower/mid 80s, falling into the upper 70s by the middle of October...so enjoy the warmer temperatures while you can? While warm temperatures remain, moisture returns Thursday into Friday along the backside of a subtropical high pressure centered well offshore over the Atlantic, bringing some low rain chances to return.

AVIATION /18Z SATURDAY THROUGH THURSDAY/

18Z TAFs - VFR conditions continue in Sunday with winds becoming light and variable overnight.

Extended Aviation Outlook: VFR.

MARINE

Through Tonight: Winds will continue to decrease this afternoon and evening, with seas similarly decreasing in intensity. The 6 foot waves will be pushing off into the waters 60+ nm offshore, allowing for the last remaining Small Craft Advisory for the waters from Savannah to Altamaha Sound GA from 20-60nm offshore to expire overnight.

Sunday through Thursday: Fairly tranquil marine conditions will be on tap through the period as high pressure becomes the dominant feature across the local waters. Lingering long-period swell associated with the departing nor'easter will continue to gradually diminish Sunday. Northwesterly flow around 5 to 10 kt on Sunday morning will gradually turn more west to southwest in the evening. Seas will generally range from 2 to 3 ft in the nearshore waters and 3 to 4 ft in the offshore waters. As high pressure shifts eastward on Tuesday and Wednesday, a weak coastal sea breeze circulation becomes more established. Expect winds to become more south to southeast on Tuesday and Wednesday as well.

Rip Currents: A lingering 10-12s backswell directed towards the Georgia and Florida coasts will support a moderate rip current risk from Tybee Island south to Sapelo Island through this evening and then again tomorrow. A low risk is anticipated for the lower South Carolina beaches both days.

CHS WATCHES/WARNINGS/ADVISORIES

GA...None. SC...Coastal Flood Advisory from 7 PM to 11 PM EDT this evening for SCZ149-150. MARINE...Small Craft Advisory until 4 AM EDT Sunday for AMZ384.