Public Information Statement
Issued by NWS Portland, ME
NOUS41 KGYX 211112
- KGYX 211111
Public Information Statement
National Weather Service Gray ME
0711 AM EDT Thu Jul 21 2016
The National Weather Service has declared the week of July 18th through
22nd, HURRICANE AWARENESS WEEK in New England. This is the first in
a series of five public information statements to be issued by the
National Weather Service Office in Gray, containing information on
hurricanes and hurricane safety.
TROPICAL CYCLONES, TROPICAL STORMS AND HURRICANES--THE BASICS
The term "tropical cyclone" is a generic name given to a low pressure
system that generally forms in the tropics and is accompanied by
showers and thunderstorms and a counterclockwise wind circulation.
Depending on the strength of the winds in the circulation, tropical
cyclones are further divided into tropical depressions, tropical
storms, and hurricanes.
The tropical cyclones that affect eastern North America generally form
in either the tropical Atlantic Ocean, the Caribbean Sea, or in the
Gulf of Mexico. The three main conditions which favor tropical
cyclone development are (1) warm ocean waters, (2) atmospheric
moisture, and (3) relatively light winds aloft. In addition, an
atmospheric disturbance, called a tropical wave, is needed to initiate
the development the counter-clockwise wind circulation. If the
favorable conditions persist for a sufficient amount of time, the
tropical disturbance can strengthen to a TROPICAL DEPRESSION, TROPICAL
STORM, or HURRICANE. When the winds in a tropical cyclone reach
tropical storm strength (39 mph, 34 kt), the storm is "named".
Tropical cyclones are classified as follows:
Tropical Depression - An organized system of clouds and thunderstorms
with a defined surface circulation and maximum sustained winds of 38
mph (33 knots) or less.
Tropical Storm - An organized system of strong thunderstorms with a
defined surface circulation and maximum sustained winds of 39-73 mph
Hurricane - An intense tropical weather system of strong
thunderstorms with a well-defined surface circulation and maximum
sustained winds of 74 mph (64 knots) or higher. Hurricanes are also
classified into different categories based on strength.
The well-developed hurricane consists of an eye, an eyewall, and
spiral bands of showers and thunderstorms. In the eye, winds are
relatively calm and there is a gentle sinking motion in the
atmosphere which leads to mostly clear skies. Surrounding the eye
is the eyewall which contains the most violent winds, the most
intense showers and thunderstorms, and can contain tornadoes. The
winds in the eyewall also have the greatest potential for causing
a deadly storm surge. Outside the eyewall, spiral bands of showers
and thunderstorms rotate around the storm. These bands of showers
and thunderstorms can also be very intense, can move into an area
very rapidly, and are the most likely area in the hurricane for
tornadoes to form.
Hurricanes and tropical storms bring with them four main threats:
high winds, coastal storm surge, inland fresh water flooding, and
tornadoes. These will be discussed in greater detail in forthcoming
While hurricane season lasts from June through November, the peak
of the season is from mid-August through October. Each year, an
average of ten tropical storms develop over the Atlantic Ocean,
Caribbean Sea, and Gulf of Mexico. Many of these storms remain over
the ocean, and an average of six of these storms become hurricanes
each year. During an average 3-year period, roughly five hurricanes
strike the United States coastline, killing approximately 45 people
(an average of 15.5 per year) anywhere from Texas to Maine. Of these,
two are typically "major" or "intense" hurricanes (winds greater
than 110 mph).
QUESTION OF THE DAY: How are hurricanes named and what names will
be used during 2016?
Women`s names were first used to name tropical storms and hurricanes
during World War II, with some variations in practices in the early
1950s. In 1953, the U.S. Weather Bureau began using a standardized
list of female names in naming Atlantic tropical storms and
hurricanes. The practice of using female names exclusively ended in
1979 when both male and female names were included in lists for the
Atlantic and Gulf of Mexico hurricane lists. The name lists are
agreed upon at international meetings of the World Meteorological
Organization. The names alternate between male and female names,
and have an international flavor because hurricanes affect other
nations and are tracked by the public and weather services of many
There are currently six lists of names used in naming hurricanes; a
different list is used each year. The lists are repeated in 6-year
cycles. However, names associated with storms that have caused
significant death and/or damage are usually retired from the list
and a replacement name is selected by the World Meteorological
Below is the list of names that have been or will be used for 2016.
Alex Bonnie Colin Danielle Earl Fiona
Gaston Hermine Ian Julia Karl Lisa
Matthew Nicole Otto Paula Richard Shary
Tobias Virginie Walter
Note that the letters Q, U, X, Y, and Z are not used in the list due
to the scarcity of names beginning with those letters.
FACT FOR THE DAY: The name hurricane is derived from the Caribbean
God of Evil, Hurican. The unpredictable behavior, high seas, and
devastating winds have been our nemesis for centuries.
For additional information about hurricanes and hurricane safety,
visit the National Hurricane Center`s web site at:
National Weather Service