Winter Storm

Winter Storm Jonas: Record Coastal Flooding Strikes New Jersey

Winter Storm Jonas delivers a powerful blast to the Eastern Seaboard in the form of stuff northeasterly winds. Those winds are driving Atlantic Ocean water toward shore and caused record storm tides along portions of the New Jersey and Delaware coastlines on Saturday. At one point, the National Weather Service had issued hurricane force wind warnings for the New Jersey coast. Those warnings have since been allowed to expire.

In addition to the record snow totals in the East, Winter Storm Jonas earlier produced heavy ice accumulation in the Carolinas, knocking out power to more than 100,000 customers in North Carolina alone.

(MORE: Latest Forecast)

Damaging Winds

The squeeze play between the intensifying low-pressure center of Jonas off the Eastern Seaboard and high pressure over eastern Canada has spawned a swath of damaging winds along the Mid-Atlantic coast.

Sustained winds have topped 50 mph at several locations from Virginia Beach, Virginia, to the New Jersey shore. Assateague Island, Virginia, clocked an 85-mph gust between 3:40 and 4:40 a.m. Saturday. Dewey Beach, Delaware, saw peak wind gust of 75 mph at 7:35 a.m. EST. Lewes, Delaware, has seen peak sustained winds of 59 mph at 6:24 a.m. EST with gusts reaching 73 mph at 6:18 a.m. EST.

Parts of New Jersey's shore have also seen wind gusts exceed 60 mph.

As predicted well in advance by computer forecast models, a streak of extremely strong east-northeasterly winds developed just north of Jonas' parent low as it moves off the East Coast. Doppler radars across the region showed winds greater than 80 mph as low as 500 feet above the ground over parts of Delaware and Maryland in the pre-dawn hours Saturday.

Wind gusts reached to exceeded 70 mph in at least five states from Winter Storm Jonas and gusty winds will linger into early Sunday.

As Jonas moves out to sea, some gusts over 50 mph remain possible on Cape Cod, Nantucket Island, and Martha's Vineyard Sunday.

Even though the snow has wound down, winds can still produce blizzard or near-blizzard conditions from blowing and drifting snow, particularly in rural areas.

(MORE: A History-Making Storm? | The Most Extreme Winter Storms)

Coastal Flooding

Wind direction, speed, duration and the length of the wind flow over water, or fetch, all determine the amount of coastal surge flooding and battering waves atop the surge in any non-tropical or tropical cyclone.

In this case, parts of the Mid-Atlantic and southeast New England coasts have experienced or are continuing to experience about a 24- to 36-hour period of strong onshore winds.

With a full moon this weekend, astronomical morning high tides are running higher than usual. This means the water level attributable to the forces of the moon are several inches higher than most of the other high tides this month, and have worsened coastal flooding impacts as it adds to the water rise driven by strong winds blowing onshore.

Record flooding was observed in at least four locations Saturday morning along the Delaware (Lewes) and New Jersey coasts (Great Channel at Stone Harbor, Cape May Harbor, Delaware Bay at Cape May). Below is a photo of the flooding in Wildwood, New Jersey.

Flooding on the New Jersey coast Saturday morning.
(Wildwood Police Department)

Areas of particular concern for additional coastal flooding at high tide Sunday morning include:

Delaware, including both Delaware Bay and the Atlantic beaches
The Jersey shore, including the south shore of Raritan Bay

The National Weather Service has issued coastal flood warnings for the Atlantic coast from the Outer Banks of North Carolina all the way to Long Island, as well as the New York and Connecticut shores of Long Island Sound. Minor to moderate coastal flooding will persist into early Sunday, particularly from the Delmarva region to the coasts of New Jersey and Long Island.

Other areas with a chance of minor to moderate coastal flooding include the south shore of Massachusetts Bay, Cape Cod, Martha's Vineyard and Nantucket Island.

(MORE: See Your Tide Predictions)

Ice

For at least a period of time, subfreezing air trapped near the ground was overrun by above-freezing, moist air aloft over parts of the East, especially the Carolinas and southern Virginia.

As of Friday night, as much as 1 inch of glaze ice was reported near Old Liberty, Virginia. 1/2 inch of glaze ice was reported at Emit, North Carolina. Ice across the Carolinas caused downed trees and power lines, resulting in tens of thousands of power outages.

Most of the ice associated with Winter Storm Jonas has come to an end, but spotty freezing drizzle may linger in some areas through part of Saturday.

(MORE: Latest Winter Storm Jonas Updates)

Check back with us at weather.com and The Weather Channel for the latest on Winter Storm Jonas.