System off the East Coast to Product Dangerous Conditions

Potential Impacts

High surf with large breaking waves and rip currents can be expected, for the most part, through the weekend from the New Jersey shore southward to at least the northern Outer Banks of North Carolina.

Even experienced swimmers should stay out of the water due to the rip current threat. Look for surf hazard warning flags and heed the advice of lifeguards. 

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Wind/Wave Model Forecast

Potential open-ocean wave heights in feet are showing in the contours. Darker color streamlines indicate stronger surface winds

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Rainfall Outlook

Locally heavier totals may occur where areas of rain persist for an hour or so. This is meant as a general outlook indicating areas with the highest threat for heavy rain.

This long fetch, or distance, these onshore winds travel over the ocean plus the duration of these winds lasting possibly through the weekend is setting the stage for not simply high surf or rip currents, but also coastal flooding and possibly some beach erosion. 

For the next couple of days, any coastal flooding is expected to be primarily of the minor or nuisance variety from North Carolina's northern Outer Banks to southeast Virginia. 

However, these persistent onshore winds increasing later this week into the weekend will continue to buildup water at the coast with greater areal coverage and magnitude of coastal flooding particularly during each high tide cycle.

If that isn't enough, astronomical high tides will rise as well this weekend with the full moon (a blood red "supermoon", no less).

The risk of moderate coastal flooding is greatest later this week into the weekend in the northern Outer Banks and the Virginia Tidewater (including Chesapeake Bay). However, coastal flooding should also increase farther north along the Delmarva peninsula, and possibly along parts of the Jersey shore. As of Tuesday night, coastal flood advisories and statements had been issued for portions of this area.

Waves riding atop the higher water levels may lead to some beach erosion in some areas, including highly vulnerable Highway 12 in the Outer Banks.

http://www.weather.com/forecast/regional/news/coastal-flood-heavy-rain-threats-mid-atlantic-carolinas-sep2015