Coastal Flooding, High Surf, Rip Currents, Heavy Rain Threat From North Carolina's Outer Banks to New Jersey (FORECAST)

Jon Erdman
Published: September 22,2015

A system off the East Coast may never become a named subtropical or tropical cyclone. However, its impacts could be dangerous into the upcoming weekend from parts of the Carolinas to the Mid-Atlantic seaboard.

Potential Impacts

High surf with large breaking waves and rip currents can be expected, for the most part, through the weekend from Long Island's ocean beaches 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.
(WATCH: The Formation/Danger of Rip Currents)

Wind/Wave Model Forecast

Rainfall Outlook

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 potentially picking up a bit 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 into early next week and in some locations, may reach their peaks of the month.
The risk of moderate coastal flooding is greatest later this week in the northern Outer Banks and the Virginia Tidewater (including Chesapeake Bay). However, coastal flooding may 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.
(MORE: "Sunny Day" Coastal Flooding More Common)
Then there's the threat of pockets of locally heavy rain occasionally wrap onshore.
With rivers, inlets and bays unable to drain as fast due to the pileup of water at the coast, any heavy rain would only compound any flooding in these areas.
(FORECAST: Kitty Hawk, North Carolina | Norfolk, Virginia | Rehoboth Beach, Delaware)

The Science Behind the Coastal Setup

Current Radar/Satellite

Coastal Setup Later This Week

First off, low pressure off the coast of the Carolinas has only a low chance of developing into a subtropical cyclone.
(MORE: What is a Subtropical Storm?)
As has been the case often this season, wind shear is currently too strong to allow any tropical or subtropical development.
(MORE: El Niño May End Hurricane Season Early)
Despite the low chance of development, a stuck weather pattern is shaping up to make a getaway to the beaches of the Carolinas and parts of the Mid-Atlantic states less than ideal, to put it mildly.
First, the polar branch of the jet stream will remain well to the north over eastern Canada or northern New England, ensuring little change in the weather over the eastern U.S. into the weekend.
(MAPS: Daily Jet Stream Forecasts)
At the surface, high pressure will build into eastern Canada and northern New England later this week.
Meanwhile, stubborn low pressure will linger somewhere off the coast of the Carolinas possibly crawling slowly northward off the Mid-Atlantic seaboard into the weekend or early next week.
The pressure difference, or gradient, between these two features will maintain that persistent onshore wind from the Atlantic Ocean toward the Outer Banks of North Carolina, Virginia Tidewater, Delmarva Peninsula, and Jersey shore the next several days.
Check back with us at weather.com and The Weather Channel for updates.

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