Nor'easter Expected To Bring Heavy Rain, Strong Winds, Beach Erosion To The Northeast, Mid-Atlantic

By Linda Lam
Published: October 21,2014



 
A nor'easter is in the early stages of development over the Northeast, and it could be a long duration event for many people.
An upper-atmospheric area of low pressure sliding southeast from the Great Lakes has spawned an area of low pressure. This low was over the Delmarva Peninsula late Tuesday evening and will quickly slide off the Atlantic coast, then remain off the New England coast through at least Thursday. The low will also intensify as it meanders off the Eastern Seaboard.
This low will combine with a strong surface high pressure system in eastern Canada to create a tight pressure gradient which will bring strong easterly to northeasterly winds into parts of the Northeast. This is an onshore wind for parts of New England, raising concerns for coastal flooding and beach erosion due to the prolonged duration and long fetch of these winds, particularly from the North Shore region of Massachusetts into Downeast Maine.
The subtropical jet stream will also move north which will bring tropical moisture northward, enhancing the rainfall across the region.
Anywhere from the northern Mid-Atlantic to New England will likely be affected by heavy rain and strong winds. The exact track of the low will determine the timing and location of the heaviest rain and strongest winds.
(FORECAST: Washington, DC | New York | Boston | Portland, Maine)
Already Tuesday evening there were some pockets of flooding from heavy rain around Baltimore as well as to the north in northern New Jersey. However, the strongest winds and heaviest rain will most likely occur on Wednesday and Thursday, with over four inches of rain possible in some areas of Maine, New Hampshire and possibly Vermont.
Excessive rainfall and localized flooding, especially near rivers and streams, are likely. Flood watches have been posted for parts of New England. But there is also some good news.
First of all, parts of the Northeast really need the rain. Portions of southern New England and the lower Hudson Valley of New York are in a moderate drought, according to the most recent U.S. Drought Monitor.
Secondly, the coldest air will stay locked up in Canada, so the only chance for snow during this event is Tuesday night into Wednesday in the central Appalachians where a few snow showers are possible above 2500 feet.
With that said, the Mid-Atlantic and Northeast needs to be ready for localized flooding, high surf and beach erosion now through Friday.

What is a Nor'easter?

A nor'easter gets its name from the strong northeasterly winds blowing over coastal areas. They are most common between September and April and form off the East Coast of the U.S.
Nor'easters usually develop where cold air from Canada meets warm air from the Gulf of Mexico and Atlantic. The Gulf Stream remains relatively warm during the fall and winter, which helps warm the colder air over the water. This temperature difference then fuels the storms.
Nor'easters are not always associated with snow, though wintry conditions do occur during these events. Typical nor'easters do bring heavy rain, strong winds, coastal flooding and beach erosion to the eastern coast of the U.S.