Definição e significado de Nor'easter

  Satellite image of the intense nor'easter responsible for the North American blizzard of 2006. Note the hurricane-like eye at the center.

A nor'easter (also northeaster; see below) is a type of macro-scale storm along the East Coast of the United States and Atlantic Canada, so named because the storm travels to the northeast from the south and the winds come from the northeast, especially in the coastal areas of the Northeastern United States and Atlantic Canada. This type of storm has characteristics similar to a hurricane. More specifically it describes a low-pressure area whose center of rotation is just off the East Coast and whose leading winds in the left forward quadrant rotate onto land from the northeast. The precipitation pattern is similar to that of other extratropical storms. Nor'easters also can cause coastal severe flooding, coastal erosion, hurricane force winds, blizzard conditions, these conditions are usually accompanied with heavy snow or rain depending on when the storm occurs. Nor'easters can occur at any time of the year but are known mostly for their presence in the winter season.^[1] Nor'easters can be devastating and damaging, especially in the winter months, when most damage and deaths are cold-related, as nor'easters are known for bringing extremely cold air down from the Arctic air mass. Nor'easters thrive on the converging air masses; that is, the polar cold air mass and the warmer ocean water of the Gulf Stream.^[2]

  Geography and formation characteristics

Nor'easters form along the East Coast of the United States, usually in the months between October and April, although nor'easters can form any time of the year.^[3] When a nor'easter starts forming in the Gulf of Mexico, moist air and high dew points feed into the developing storm. The storm will then reach the Atlantic Ocean and begin to strengthen. Some nor'easters will increase rapidly in intensity, sometimes becoming as strong as moderate hurricanes by feeding on the warm waters of the Gulf Stream.^[4]

The sharp contrast in the cold Labrador current and the warm Gulf Stream, as well as the topographic nature of the Northeast, make the Mid-Atlantic and New England coast one of the most conducive areas in the world for nor'easter formation.^[1] It is thought that nor'easters are caused by the Arctic oscillation, which is a band of air circulating at about 55°N. The Arctic oscillation has two phases: positive and negative. In the positive phase, the predominant phase for the past twenty years, the air moves quickly and acts almost like a dam in preventing the intrusion of Arctic air into the mid-latitude regions. In its negative phase, the air moves more slowly and is more subject to disruption. This allows cold Arctic air to penetrate into the mid-latitudes. There can be a fluctuation between positive phase and negative phase days over the course of a winter, and a correlation between negative phase days and nor'easters has been found.^[1]

  Formation

Most nor'easters start from a low-pressure system that forms in the south, most often the Gulf of Mexico, and are drawn across to the Northeast by the Jet Stream. The divergence or diffluence in the upper atmosphere caused by the Jet Stream removes and disperses the rising air at a faster rate than it is replaced at the surface, which, along with the Coriolis Force, creates and develops a storm. Their northeast track brings them up along the East Coast past the mid-Atlantic and New England coastal states. The counterclockwise flow around a low-pressure system brings the warm moist oceanic air over land. The warm moist air meets cold air carried southward by the trough. The low enhances the surrounding pressure gradient, which acts to spiral the very different air masses toward each other at an even faster rate. The greater the temperature differences between the two air masses the greater the turbulence and instability, and the more severe the storm can become.^[1][3]

The nor'easters taking the East Coast track usually indicates the presence of a high-pressure area in the vicinity of Bermuda.^[5] The storm will then reach the North Carolina coast, which is in the Southeast, and begin to develop. At this time, either the nor'easter can move slightly inland and present mostly rain or it can move slightly offshore, growing stronger and increasing its potential to be destructive. In the latter case, the effects of the storm can reach the major cities of the Northeast, such as New York City.^[1] 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 strong hurricane. It then meanders throughout the North Atlantic and can last for several weeks.^[1]

  Characteristics

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. It is not uncommon for residual cloud cover to last for several days after the height of the storm. 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, although they are well known for their frozen precipitation. 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 1979, the center of the storm can take on the circular shape more typical of a hurricane and have a small 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.

  Difference from Euroclydons

Nor'easters are often mistaken for Euroclydons, but these are two separate weather patterns. A Euroclydon is a tempestuous northeast wind that blows in the Mediterranean.

  Areas often affected

The northeastern United States, from Virginia to the New England coast, Quebec and Atlantic Canada can experience nor'easters, most often in the winter and early spring but also sometimes during the autumn. These storms can sometimes last for several days, leaving inches of rain or several inches (or feet) of snow on the region.

The Atlantic coast, from northern Georgia northward up the coast, can suffer high winds, pounding surf, and extremely heavy rains during these storms. However, swells have been known to cause damage through the Caribbean as well. Surfers wait in anticipation when a nor'easter is formed. Nor'easters cause a significant amount of severe beach erosion in these areas, as well as flooding in the associated low-lying areas. Beach residents in these areas may actually fear the repeated depredations of nor'easters over those of hurricanes, because nor'easters happen more frequently and cause substantial damage to beach-front property and their dunes.

  Impacts

Nor'easters usually bring massive amounts of precipitation, high winds, large waves, and marginal storm surge to coastal areas. Depending on the circumstances and the time of year, nor'easters can bring rain, ice, and snow. Ice, snow, and high winds can shut down major airports for days leaving thousands stranded. Ice and snow can also shut down major highways and interstates leaving motorists unable to reach their destinations. During nor'easters, many people lose power because of high winds, ice, and snow.

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

  "Nor'easter" usage and origins

  Compass card (1607)

The term nor'easter came to American English by way of British English.^{[citation needed]} According to the Oxford English Dictionary (OED), the first recorded use in the English language of the term "nore" ("north") in association with the points of the compass and wind direction was by Dekker in 1612: "How blowes the winde Syr?" "Wynde! is Nore-Nore-West."

Similar uses occurred in 1688 (… Nore and Nore-West …) and in 1718 (… Nore-west or Nore-nore-west.). These recorded uses are predated by use of the term "noreast", first recorded as used by Davis in 1594 (Noreast by North raiseth a degree in sayling 24 leagues.) and shown, for instance, on a compass card published in 1607. Thus, the manner of pronouncing from memory the 32 points of the compass, known in maritime training as "boxing the compass", is described by Ansted^[6] with pronunciations "Nor'east (or west)," "Nor' Nor'-east (or west)," "Nor'east b' east (or west)," and so forth. According to the OED, the first recorded use of the term "nor'easter" occurs in 1836 in a translation of Aristophanes. The term "nor'easter" naturally developed from the historical spellings and pronunciations of the compass points and the direction of wind or sailing.^{[citation needed]}

As noted in a January 2006 editorial by William Sisson, editor of Soundings magazine,^[7] use of "nor'easter" to describe the storm system is common along the U.S. East Coast. Yet it has been asserted by linguist Mark Liberman (see below) that "nor'easter" as a contraction for "northeaster" has no basis in regional New England dialect and is a "fake" word. However, this view neglects the little-known etymology and the historical maritime usage described above.

Nineteenth-century Downeast mariners pronounced the compass point "north northeast" as "no'nuth-east," and so on.^{[citation needed]} For decades, Edgar Comee, of Brunswick, Maine, waged a determined battle against use of the term "nor'easter" by the press, which usage he considered a pretentious and altogether lamentable affectation and the odious, even loathsome, practice of landlubbers who would be seen as salty as the sea itself. His efforts, which included mailing hundreds of postcards, were profiled, just before his death at the age of 88, in The New Yorker.^[8]

Despite the efforts of Comee and others, use of the term continues by the press. According to Boston Globe writer Jan Freeman, from 1975 to 1980, journalists used the nor’easter spelling only once in five mentions of such storms; in the past year (2003), more than 80 percent of northeasters were spelled nor'easter.^[9]

University of Pennsylvania linguistics professor Mark Liberman has pointed out that while the OED cites examples dating back to 1837, these examples represent the contributions of a handful of non-New England poets and writers. Liberman posits that "nor'Easter" may have originally been a literary affectation, akin to "e'en" for "even" and "th'only" for "the only", which is an indication in spelling that two syllables count for only one position in metered verse, with no implications for actual pronunciation.^[10]

However, despite these assertions, the term can be found in the writings of New Englanders going back at least to the 19th century.

• Thomas Bailey Aldrich, in his semi-autobiographical work The Story of the Bad Boy (1870), wrote We had had several slight flurries of hail and snow before, but this was a regular nor'easter.[1]

• In The Gray Goth (1869) Elizabeth Stuart Phelps Ward wrote ...and there was snow in the sky now, setting in for a regular nor'easter.[2]

• John H. Tice, in A new system of meteorology, designed for schools and private students (1878), wrote During this battle, the dreaded, disagreeable and destructive Northeaster rages over the New England, the Middle States, and southward. No nor'easter ever occurs except when there is a high barometer headed off and driven down upon Nova Scotia and Lower Canada.[3])

Usage existed into the 20th century in the form of:

• Current event description, as the Publication Committee of the New York Charity Organization Society wrote in Charities and the commons: a weekly journal of philanthropy and social advance, Volume 19 (1908): In spite of a heavy "nor'easter," the worst that has visited the New England coast in years, the hall was crowded.[4]

• Historical reference, as used by Mary Rogers Bangs in Old Cape Cod (1917): In December of 1778, the Federal brig General Arnold, Magee master and twelve Barnstable men among the crew, drove ashore on the Plymouth flats during a furious nor'easter, the "Magee storm" that mariners, for years after, used as a date to reckon from.[5]

• A common contraction for "northeaster", as listed in Ralph E. Huschke's Glossary of meteorology (1959).[6]

  Notable nor'easters

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 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 blizzard of 1978 - A catastrophic storm, which dropped over 27 inches of snow in areas of New England, kills a total of 100 people, mainly people trapped in their cars on the highway.
• 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 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 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.
• Nor'Ida (2009) - Formed from the remants of Hurricane Ida, produced moderate storm surge, strong winds and very heavy rainfall throughout the mid-atlantic region. It caused 300 million (2009 USD) in damage, and killed 6 people.
• The December 2010 North American blizzard - was a major blizzard which affected large metropolitan areas including Philadelphia, New York City, Providence, and Boston. In some of these areas, the storm brought up to 2 feet of snow.
• 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.

  See also

• Alberta clipper
• Panhandle hook
• Sudestada
• Winter storm
• List of NESIS storms
• Cold-core low

  Notes

  External links

• "NOR'EASTERS: Comprehension, Preparation and Survival". Multi-Community Environmental Storm Observatory (MESO). October 2002. Archived from the original on February 5, 2007. http://web.archive.org/web/20070205065408/http://www.mcwar.org/articles/noreasters/NorEasters.html. Retrieved March 20, 2007. 
• Blizzard Video: Dec 9, 2005 (duration: 9m59sec)
• Archived issues of NOR'EASTER (Magazine of the Northeast Sea Grant Programs), published until 1999.
• Duxbury, Massachusetts April 2007 Nor'easter photos