WRN – What is a Nor’easter?


Weather forecasters at NWS local forecast offices around the country and at the National Centers for Environmental Prediction near Washington, D.C., monitor conditions conducive for Nor’easters, especially during the fall and winter. When they see conditions are favorable in the upcoming days, forecasters may issue winter storm, blizzard, high wind and coastal flood watches to alert the public that some of the worst effects of Nor’easters might be possible. If conditions are imminent, those watches are changed to warnings.

Follow weather.gov to get the latest forecasts and warnings. If a Nor’easter threatens your home town, take steps to prepare, such as having three days of food, water and other provisions in a disaster supplies kit. A Nor’easter could cut power and leave you in the dark. Also, sit down with your family and create an emergency communications plan so your loved ones know how to stay in touch if you are separated. Stay off the roads if advised by local authorities and never drive into flood waters. These simple actions will help you stay safe during a Nor’easter

Nor’easter is a macro-scale cyclone. The name derives from the direction of the strongest winds—as an offshore air mass rotates counterclockwise, winds tend to blow northeast-to-southwest over the region covered by the northwest quadrant of the cyclone. Use of the term in North America is associated with several different types of storms, some of which can form in the North Atlantic Ocean and some of which form as far south as the Gulf of Mexico. The term is most often used in the coastal areas of New England and the Mid-Atlantic states. Typically, such storms originate as a low-pressure area that forms within 100 miles (160 km) of the shore between North Carolina and Massachusetts.

The precipitation pattern is similar to that of other extratropical storms. Nor’easters are usually accompanied by very heavy rain or snow, and can cause severe coastal flooding, coastal erosion, hurricane-force winds, or blizzard conditions. Nor’easters are usually most intense during winter in New England and Atlantic Canada. They thrive on converging air masses—the cold polar air mass and the warmer air over the water—and are more severe in winter when the difference in temperature between these air masses is greater.

Nor’easters tend to develop most often and most powerfully between the months of November and March, although they can (much less commonly) develop during other parts of the year as well. The susceptible regions are generally impacted by Nor’easters a few times each winter

Nor’easters develop in response to the sharp contrast in the warm Gulf Stream ocean current coming up from the tropical Atlantic and the cold air masses coming down from Canada. When the very cold and dry air rushes southward and meets up with the warm Gulf stream current, which is often near 70 °F (21 °C) even in mid-winter, intense low pressure develops.

In the upper atmosphere, the strong winds of the jet stream remove and replace rising air from the Atlantic more rapidly than the Atlantic air is replaced at lower levels; this and the Coriolis force help develop a strong storm. The storm tracks northeast along the East Coast past the Carolinas, the mid-Atlantic, and the New England coastal states. ounterclockwise winds around the low-pressure system blow the moist air over land. The relatively warm, moist air meets cold air coming southward from Canada. The low increases the surrounding pressure difference, which causes the very different air masses to collide at a faster speed. When the difference in temperature of the air masses is larger, so is the storm’s instability, turbulence, and thus severity.

The nor’easters taking the East Coast track usually indicates the presence of a high-pressure area in the vicinity of Nova Scotia. Sometimes a nor’easter will move slightly inland and bring rain to the cities on the coastal plain (New York City, Philadelphia, Baltimore, etc.) and snow in New England (Boston northward). It can move slightly offshore, bringing a wet snow south of Boston to Richmond, Virginia, or even parts of the Carolinas. Such a storm will rapidly intensify, tracking northward and following the topography of the East Coast, sometimes continuing to grow stronger during its entire existence. A nor’easter usually reaches its peak intensity while off the Canadian coast. The storm then reaches Arctic areas, and can reach intensities equal to that of a weak hurricane. It then meanders throughout the North Atlantic and can last for several weeks.


Nor’easters are usually formed by an area of vorticity associated with an upper-level disturbance or from a kink in a frontal surface that causes a surface low-pressure area to develop. Such storms are very often formed from the merging of several weaker storms, a “parent storm”, and a polar jet stream mixing with the tropical jet stream.

Until the nor’easter passes, thick, dark, low-level clouds often block out the sun. Temperatures usually fall significantly due to the presence of the cooler air from winds that typically come from a northeasterly direction. During a single storm, the precipitation can range from a torrential downpour to a fine mist. All precipitation types can occur in a nor’easter. High wind gusts, which can reach hurricane strength, are also associated with a nor’easter.

On very rare occasions, such as in the North American blizzard of 2006 and a nor’easter in 1978, the center of the storm can take on the circular shape more typical of a hurricane and have a small “dry slot” near the center, which can be mistaken for an eye, although it is not an eye.

Difference from tropical cyclones

Often, people mistake nor’easters for tropical cyclones and do not differentiate between the two weather systems. Nor’easters differ from tropical cyclones in that nor’easters are cold-core low-pressure systems, meaning that they thrive on cold air. Tropical cyclones are warm-core low-pressure systems, which means they thrive on warm temperatures.

Difference from other extratropical storms

A nor’easter is formed in a strong extratropical cyclone, usually experiencing bombogenesis. While this formation occurs in many places around the world, nor’easters are unique for their combination of northeast winds and moisture content of the swirling clouds. Nearly similar conditions sometimes occur during winter in the Pacific Northeast (northern Japan and northwards) with winds from NW-N. In Europe, similar weather systems with such severity are hardly possible; the moisture content of the clouds is usually not high enough to cause flooding or heavy snow, though NE winds can be strong.


The eastern United States, from North Carolina to Maine, and Eastern Canada can experience nor’easters, though most often they affect the areas from northern New Jersey northward. The effects of a nor’easter sometimes bring high tides and strong winds as far south as coastal South Carolina and Georgia. Surfers wait in anticipation when a nor’easter is formed. Nor’easters cause a significant amount of beach erosion in these areas, as well as flooding in the associated low-lying areas.

Biologists at the Woods Hole Oceanographic Institution on Cape Cod have determined nor’easters are an environmental factor for red tides on the Atlantic coast.

Here is a list of notable nor’easters, followed by a short description about the event.

The Great Blizzard of 1888 – Was one of the worst blizzards in U.S. history. Dropped 40–50 inches of snow, killed 400 people, mostly in New York.

The Great Appalachian Storm of November 1950 – A very severe storm that dumped more than 30 inches of snow in many major metropolitan areas along the eastern United States, record breaking temperatures, and hurricane-force winds. The storm killed 353 people.

The Ash Wednesday Storm of 1962 – Caused severe tidal flooding and blizzard conditions from the Mid-Atlantic to New England, killed 40 people.

The Eastern Canadian Blizzard of March 1971 – Dropped over 32 inches of snow over areas of eastern Canada, killed at least 30 people.

The Groundhog Day gale of 1976 – Caused blizzard conditions for much of New England and eastern Canada, dropping a maximum of 56 inches of snow.

The Northeastern United States “”Storm of the Century”” Blizzard of 1978 (The White Hurricane) – A catastrophic storm, A series of three winter storms battered much of the Midwest and Northeast in 1978. But it was the second blast that caused devastation in Ohio. Between Jan. 25 and 27, as much as three feet of snow fell.FOX 8 meteorologist Dick Goddard described the conditions, saying the wind chill reached 61 degrees below zero and winds were whipping at 52 mph.

The high winds created massive snow drifts, knocking out electricity and closing the Ohio Turnpike. The storm killed 70 people, including 51 in Ohio, and caused at least $100 million in damage.

The 1991 Perfect Storm (the “Perfect Storm,” combined Nor’easter/hurricane) – Very unusual storm which evolved into a hurricane, tidal surge caused severe damage to coastal areas, especially Massachusetts, killed 13 people.

The December 1992 nor’easter

The Storm of the Century (1993) – A superstorm which affected the entire eastern U.S., parts of eastern Canada and Cuba. It caused 6.65 billion (2008 USD) in damage, and killed 310 people.

The Christmas 1994 Nor’easter – An intense storm which affected the east coast of the U.S., and exhibited traits of a tropical cyclone.

The North American blizzard of 1996 – Severe snowstorm which brought up to 4 feet of snow to areas of the mid-atlantic and northeastern U.S., and killed a total of 154 people.

The North American blizzard of 2003 – Dropped over 2 feet of snow in several major cities, including Boston, and New York City, affected large areas of the Northeastern and Mid-Atlantic U.S., and killed a total of 27 people.

White Juan of 2004 – A blizzard that affected Atlantic Canada, crippling transportation in Halifax, Nova Scotia, and dropping over 37 inches of snow in areas.

The North American blizzard of 2005 – Brought blizzard conditions to southern New England and dropped over 40 inches of snow in areas of Massachusetts.

The North American blizzard of 2006 – A powerful storm that developed a hurricane-like eye when off the coast of New Jersey. It brought over 30+ inches of snow in some areas and killed 3 people.

The April 2007 nor’easter – An unusually late storm that dumped heavy snow in parts of Northern New England and Canada and heavy rains elsewhere. The storm caused a total of 18 fatalities.

Nor’Ida (2009) – Formed from the remnants of Hurricane Ida, produced moderate storm surge, strong winds and very heavy rainfall throughout the mid-atlantic region. It caused US$300 million (2009) in damage, and killed six people.

The December 2010 North American blizzard – was a major blizzard which affected large metropolitan areas, including New York City, Philadelphia, Providence, and Boston. In some of these areas, the storm brought up to 2 feet of snow.

In January 2011, two nor’easters struck the East Coast of the United States just two weeks apart and severely crippled New England and the Mid-Alantic. During the first of the two storms, a record of 40 inches was recorded in Savoy, Massachusetts. Two people were killed.

The March 2010 nor’easter – A slow-moving nor’easter that devastated the Northeastern United States. Winds of up to 70 miles per hour snapped trees and power lines, resulting in over 1 million homes and businesses left without electricity. The storm produced over 10 inches of rain in New England, causing widespread flooding of urban and low-lying areas. The storm also caused extensive coastal flooding and beach erosion.

The 2011 Halloween nor’easter – was a rare, historic nor’easter, which produced record breaking snowfall for October in many areas of the Northeastern U.S., especially New England. The storm produced a maximum of 32 inches of snow in Peru, Massachusetts, and killed 39 people. After the storm, the rest of the winter for New England remained very quiet, with much less than average snowfall and no other significant storms to strike the region for the rest of the season.

The November 2012 nor’easter – A moderately strong nor’easter that is notable for striking the same regions that were impacted by Hurricane Sandy a week earlier. The storm exacerbated the problems left behind by Sandy, knocking down trees that were weakened by Sandy. It also left several residents in the Northeast without power again after their power was restored following Hurricane Sandy. Highest snowfall total from the storm was 13 inches, recorded in Clintonville, Connecticut.

The December 25th–28th, 2012 nor’easter – A major nor’easter that was notable for its tornado outbreak across the Gulf Coast states on Christmas day as well as giving areas such as northeastern Texas a white Christmas. The low underwent secondary cyclogenesis near the coast of North Carolina and dumped a swath of heavy snow across northern New England and New York, caused blizzard conditions across the Ohio Valley, as well as an ice storm in the mountains of the Virginias.

The February 2013 nor’easter – An extremely powerful and historic nor’easter that dumped heavy snow and unleashed hurricane-force wind gusts across New England. Many areas received well over 2 feet of snow, especially Connecticut, Rhode Island, and eastern Massachusetts. The highest amount recorded was 40 inches in Hamden, Connecticut, and Gorham, Maine, received a record 35.5 inches. Over 700,000 people were left without power and travel in the region came to a complete standstill.

On the afternoon of February 9, when the storm was pulling away from the Northeastern United States, a well defined eye was seen in the center. The eye feature was no longer there the next day and the storm quickly moved out to sea. The nor’easter later moved on to impact the United Kingdom, before finally dissipating on February 20. The storm killed 18 people.

The March 2013 nor’easter – A large and powerful nor’easter that ended up stalling along the eastern seaboard due to a blocking ridge of high pressure in Newfoundland and pivoted back heavy snow and strong winds into the Northeast United States for a period of 2 to 3 days. Many officials and residents were caught off guard as local weather stations predicted only a few inches of snow and a change over to mostly rain.

That forecast failed miserably, as many areas received over a foot of snow, with the highest amount being 29 inches in Milton, Massachusetts. Several schools across the region, particularly in the Boston, Massachusetts, metropolitan area, remained in session during the height of the storm, not knowing the severity of the situation. Rough surf and rip currents were felt all the way southwards towards Florida’s east coast.

The January 2015 nor’easter – Unlike recent historical winter storms, there was no indication that a storm of this magnitude was coming until about 3 days in advance. The European computer model (ECMWF) first picked up on the potential for the nor’easter sometime before January 24. By the afternoon of January 24, most if not all major computer models were forecasting the storm to be much more severe than previously indicated earlier in the week. On the same day, the National Weather Service said they were aware about the potential for a major, crippling snowstorm but decided to hold off on winter weather headlines due to still being in the middle of another nor’easter.

The Blizzard began as an Alberta Clipper in the Midwestern States, which was forecast to transfer its energy to a new, secondary Low Pressure off the coast of the Mid Atlantic and move northeastward and pass to the south and east of New England. Before the transition began, most of the area was being affected by generally light snow on the morning and afternoon of January 26. It wasn’t until the evening into the early morning hours of January 27, that the storm was forecast to begin rapid deepening, stall, and also do a loop. It did stall for a time, however, the loop of the storm that was forecast did not happen.

Due to this the storm began to slowly pull away to the northeast, a little quicker than expected. Therefore, the forecast for western portions of the area, western Connecticut and New York City, miserably failed, with the city and its suburbs only receiving generally 4 to 6 inches, with a maximum of 9 inches recorded at Central Park. Further to the east, the storm brought over 20 inches of snow to much of the area, with several reports of over 30 inches across the State of Massachusetts, breaking many records. A maximum of 36 inches was recorded in at least four towns across Worcester County in Massachusetts and the city of Worcester itself received 34.5 inches, marking the city’s largest storm snowfall accumulation on record.

The city of Boston recorded 24.6 inches, making it the largest storm snowfall accumulation during the month of January and the city’s sixth largest storm snowfall accumulation on record. On the coast of Massachusetts, Hurricane Force gusts up to around 80 mph along with sustained winds between 50 and 55 mph at times, were reported. The storm also caused severe coastal flooding and storm surge. The storm bottomed out to a central pressure of 970mb. By January 28, the storm began to pull away from the area.

October 2015 North American storm complex – In early October, a low pressure system formed in the Atlantic, Tapping into moisture from Hurricane Joaquin, the storm dumped a huge amount of rain, mostly in South Carolina.

January 2016 blizzard – Between January 23 and 24, a very severe Nor’easter dumped 2 to 3 feet of snow in the East Coast of the United States. States of Emergencies were declared in 12 States in advance of the storm as well as by the Mayor of Washington D.C.. The blizzard also caused significant storm surge in New Jersey and Delaware that was equal to or worse than Hurricane Sandy. Sustained damaging winds over 50 mph were recorded in many coastal communities, with a maximum gust to 85 mph on Assateague Island, Virginia. A total of 55 people died due to the storm.

February 2017 blizzard – Forming as an Alberta clipper in the northern United States on February 6, the system initially produced light snowfall from the Midwest to the Ohio Valley as it tracked southeastwards. It eventually reached the East Coast of the United States on February 9 and began to rapidly grow into a powerful nor’easter, dumping 1 to near 2 feet across the Northeast Megalopolis. The storm also produced prolific thunder and lightning across Southern New England. Prior to the blizzard, unprecedented and record-breaking warmth had enveloped the region, with record highs of above 60 °F (16 °C) recorded in several areas, including Central Park in New York City. Some were caught off guard by the warmth and had little time to prepare for the snowstorm.


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