Tropical Weather
Report
above - updated
automatically at approximately 2 AM, 8
AM,
2 PM, and 8 PM EDT from June 1
to November 30
|
above - updated
automatically at approximately 2 AM, 8
AM,
2 PM, and 8 PM EDT from June 1
to November 30
|
|
2011-11-29 - 05:30 am
- Wednesday (today) marks the final day of the 2011 Atlantic hurricane season, and
it was another very odd year. The season featured a huge number of named
storms--nineteen--tying 2011 with 2010, 1995, and 1887 as the 3rd busiest year
for tropical storms. Only 2005 and 1933 had more named storms since record
keeping began in 1851. However, 2011 had an unusually low percentage of its
named storms reach hurricane strength .. the year started out with eight
consecutive tropical storms that failed to reach hurricane strength--the first
time on record the Atlantic has seen that many storms in row not reach hurricane
strength .. we had a near-average average number of hurricanes in
2011--seven--meaning that only 37% of this year's named storms made it to
hurricane strength. Normally, 55 - 60% of all named storms intensify to
hurricane strength in the Atlantic. There were three major hurricanes in 2011,
which is one above average, and the total Accumulated Cyclone Energy (ACE)--a
measure of the destructive potential of this season's storms--was about 20%
above average. The rare combination of near-record ocean temperatures but
unusually dry, stable air over the Atlantic is no doubt at least partially
responsible for 2011's unusually high count of named storms, but near-average
number of hurricanes and ACE. Both 2010 and 2011 had nineteen named storms,
making it the second busiest 2-year period in the Atlantic behind 2004 - 2005.
Even when one considers that 2 - 4 tropical storms from both 2010 and 2011 would
likely have been missed before the advent of satellites, the tropical storm
activity of 2010 - 2011 is still very remarkable (in 2011, Tropical Storm
Franklin, Tropical Storm Jose, and the unnamed 19th tropical storm of September
1 would probably have been missed before satellite technology came along, since
they were all weak, short-lived storms that did not impact land or shipping.) ..
above -
Tracks for the Atlantic tropical
cyclones of 2011
|
|
|
|
.Another below-average
hurricane season for the U.S. - for
the second consecutive year, despite a
near-record number of named storms in
the Atlantic, the U.S. had far fewer
strikes by tropical storms and
hurricanes than average. Favorable
steering currents steered most of the
storms in 2010 and 2011 past Bermuda and
out to sea. During 2010, only one
tropical storm hit the U.S., despite a
season with the 3rd highest number of
named storms--nineteen. Only two named
storms hit the U.S. in 2011: Tropical
Storm Lee, which hit Louisiana with 60
mph winds, and Hurricane Irene, which
hit North Carolina on August 27 with 85
mph winds, and made two additional
landfalls in New Jersey and New York the
next day. Tropical Storm Don hit Texas
on July 29 as a tropical depression and
did not count as a landfalling named
storm, according to post analysis by NHC.
Wind shear and dry air from the Texas
drought made Don rapidly weaken before
landfall on Padre Island National
Seashore north of Brownsville. During
the 15-year active hurricane period from
1995 - 2009, 33% of all named storms in
the Atlantic hit the U.S., and 30% of
all Atlantic hurricanes hit the U.S. at
hurricane strength. The U.S. averaged
seeing six named storms per year, with
four of them being hurricanes and two
being intense hurricanes. Thus, the
landfall of only three named storms in a
two-year period is a major departure
from what happened the previous fifteen
years. The past six years is the first
six-year period without a major
hurricane strike on the U.S. since 1861
- 1868. The last major hurricane to hit
the U.S. was Category 3 Hurricane Wilma
of October 2005. One caveat to keep in
mind, though: Hurricane Ike and
Hurricane Gustav of 2008 both hit the
U.S. as strong Category 2 hurricanes,
and had central pressures characteristic
of Category 3 hurricanes. Had these
storms occurred more than 65 years ago,
before the Hurricane Hunters, Ike and
Gustav would likely have been classified
as Category 3 hurricanes at landfall
(assuming that few quality wind
observations would have been available
at landfall, which is usually the case.)
The strongest, deadliest and longest-lived storms of
2011 - the strongest hurricane of 2011 was
Hurricane Ophelia, which peaked as a Category 4
hurricane with 140 mph winds and a central pressure
of 940 mb on October 2, when it was just northeast
of Bermuda. Ophelia hit Southeast Newfoundland as a
tropical storm with 70 mph winds on October 3, but
caused little damage. The strongest hurricane at
landfall was Hurricane Irene, whose 120-mph eyewall
winds raked Crooked Island, Long Island, Rum Cay,
Cat Island, Eleuthera, and Abaco Island in the
Bahamas. Wind gusts as high as 140 mph were reported
in the Bahamas.The longest-lived storm of 2011 was
Hurricane Phillipe, which lasted 15 days, from
September 24 to October 8. The most damaging storm
was Hurricane Irene, which caused an estimated $7.2
billion in damage from North Carolina to New
England, according to re-insurance broker AON
Benfield. Irene was also the deadliest storm of
2011, with 55 deaths in the Caribbean and U.S.
above - Pre-season Atlantic hurricane season
forecasts issued by seven major forecast groups. The
average of these forecasts called for 15 named
storms, 8 hurricanes, 4 intense hurricanes, and an
ACE index 150% of normal. The actual numbers were 19
named storms, 7 hurricanes, 3 intense hurricanes,
and an ACE index 120% of normal.
Pre-season hurricane forecasts did a decent job
- the pre-season Atlantic hurricane season forecasts
issued by seven major forecast groups were generally
decent. The average of these forecasts called for 15
named storms, 8 hurricanes, 4 intense hurricanes,
and an ACE index 150% of normal. The actual numbers
were 19 named storms, 7 hurricanes, 3 intense
hurricanes, and an ACE index 120% of normal. Phil
Klotzbach and Bill Gray of Colorado State will be
releasing their end-of-season verification and
summary of the 2011 Atlantic hurricane season on
November 30.
above - The scene in
Nassau in the Bahamas at daybreak on
August 25, 2011 during Hurricane Irene
..
|
|
|
|
|
|
Tropical Weather Overview
What Is A Tropical
Depression, Tropical Storm Or A
Hurricane
Tropical
Depression
- a tropical cyclone in which the
maximum sustained wind speed is 38
mph or less (33 kt or less or 17 m/s
or less). Depressions have a closed
circulation.
Tropical Storm - a
tropical cyclone in which the
maximum sustained wind speed ranges
from 39 mph (34 kt or 18 m/s) to 73
mph (63 kt or 33 m/s). The
convection in tropical storms is
usually more concentrated near the
center with outer rainfall
organizing into distinct bands.
Hurricane - when
winds in a tropical cyclone equal or
exceed 74 mph (64 kt or 34 m/s) it
is called a hurricane. Hurricanes
are further designated by categories
on the Saffir-Simpson scale.
Hurricanes in categories 3, 4, 5 are
known as Major Hurricanes or Intense
Hurricanes.
The Saffir-Simpson
Hurricane Wind Scale
The
Saffir-Simpson Hurrihttp://www.hpc.ncep.noaa.gov/qpf/fill_98qwbg.gifased on
the hurricahttp://whttp://www.crownweather.com/?page_id=4557 es of the type of damages and
impacts in the United States
associated with winds of the
indicated intensity. In general,
damages rise by about a factor of
four for every category increase.
The maximum sustained surface wind
speed (peak 1-minute wind at 10 m
[33 ft]) is the determining factor
in the scale. The scale does not
address the potential for such other
hurricane-related impacts, as storm
surge, rainfall-induced floods, and
tornadoes. These wind-caused impacts
are to apply to the worst winds
reaching the coast and the damage
would be less elsewhere. It should
also be noted that the general
wind-caused damage descriptions are
to some degree dependent upon the
local building codes in effect and
how well and how long they have been
enforced. Hurricane wind damage is
also dependent upon such other
factors as duration of high winds,
change of wind direhttp://www.ssd.noaa.gov/goes/flt/t2/avn-l.jpg,
and age of structures.http://www.ssd.noaa.gov/goes/flt/t2/avn-l.jpgrricane:
Sustained Winds 74-95 mph
(64-82 kt or 119-153 km/hr).
Very dangerous winds will produce
some damage
People, livestock, and pets struck
by flying or falling debris could be
injured or killed. Older (mainly
pre-1994 construction) mobile homes
could be destroyed, especially if
they are not anchored properly as
they tend to shift or roll off their
foundations. Newer mobile homes that
are anchored properly can sustain
damage involving the removal of
shingle or metal roof coverings, and
loss of vinyl siding, as well as
damage to carports, sunrooms, or
lanais. Some poorly constructed
frame homes can experience major
damage, involving loss of the roof
covering and damage to gable ends as
well as the removal of porch
coverings and awnings. Unprotected
windows may break if struck by
flying debris. Masonry chimneys can
be toppled. Well-constructed frame
homes could have damage to roof
shingles, vinyl siding, soffit
panels, and gutters. Failure of
aluminum, screened-in, swimming pool
enclosures can occur. Some apartment
building and shopping center roof
coverings could be partially
removed. Industrial buildings can
lose roofing and siding especialhttp://icons.wxug.com/metgraphics/rob/emily_ir4_20110803.jpges/at201105_sat.jpgand
http://icons.wxug.com/metgraphics/rob/emily_ir4_20110803.jpges/at201105_sat.jpg/data/images/at201105_sat.jpgd
windows will be common. Windows in
high-rise buildings can be broken by
flying debris. Falling and broken
glass will pose a significant danger
even after the storm. There will be
occasional damage to commercial
signage, fences, and canopies. Large
branches of trees will snap and
shallow rooted trees can be toppled.
Extensive damage to power lines and
poles will likely result in power
outages that could last a few to
several days. Hurricane Dolly (2008)
is an example of a hurricane that
brought Category 1 winds and impacts
to South Padre Island, Texas.
Categ-95 kt or 154http://www.ssd.noahttp://www.ssd.noaa.gov/goes/flt/t2/avn-l.jpg
There is a substantial risk of
injury or death to people,
livestock, and pets due to flying
and falling debris. Older (mainly
pre-1994 construction) mobile homes
have a very high chance of being
destroyed and the flying debris
generated can shred nearby mobile
homes. Newer mobile homes can also
be destroyed. Poorly constructed
frame homes have a high chance of
having their roof structures removed
especially if they are not anchored
properly. Unprotected windows will
have a high probability of being
broken by flying debris.
Well-constructed frame homes could
sustain major roof and siding
damage. Failure of aluminum,
screened-in, swimming pool
enclosures will be common. There
will be a substantial percentage of
roof and siding damage to apartment
buildings and industrial buildings.
Unreinforced masonry walls can
collapse. Windows in high-rise
buildings can be broken by flying
debris. Falling and broken glass
will pose a significant danger even
after the storm. Commercial signage,
fences, and canopies will be damaged
and often destroyed. Many shallowly
rooted trees will be snapped or
uprooted and block numerous roads.
Near-total power loss is expected
with outages that could last from
several days to weeks. Potable water
could become scarce as filtration
systems begin to fail. Hurricane
Frances (2004) is an example of a
hurricane that brought Category 2
winds and impacts to coastal
portions of Port St. Lucie, Florida
with Category 1 conditions
experienced elsewhere in the city.
Category Three Hurricane: Sustained
Winds 111-130 mph http://www.ssd.noaa.gov/eumet/eatl/avn-l.jpgd.noaa.gov/eumet/eatl/avn-l.jpgd.noaa.gov/eumet/eatl/avn-l.jpg
178-209 km/hr).
Devastating damage will occur
There is a high risk of injury or
death to people, livestock, and pets
due to flying and falling debris.
Nearly all older (pre-1994) mobile
homes will be destroyed. Most newer
mobile homes will sustain severe
damage with potential for complete
roof failure and wall collapse.
Poorly constructed frame homes can
be destroyed by the removal of the
roof and exterior walls. Unprotected
windows will be broken by flying
debris. Well-built frame homes can
experience major damage involving
the removal of roof decking and
gable ends. There will be a high
percentage of roof covering and
siding damage to apartment buildings
and industrial buildings. Isolated
structural damage to wood or steel
framing can occur. Complete failure
of older metal buildings is
possible, and older unreinforced
masonry buildings can collapse.
Numerous windows will be blown out
of high-rise buildings resulting in
falling glass, which will pose a
threat for days to weeks after the
storm. Most commercial signage,
fences, and canopies will be
destroyed. Many trees will be
snapped or uprooted, blocking
numerous roads. Electricity and
water will be unavailable for
several days to a few weeks after
the storm passes. Hurricane Ivan
(2004) is an example of a hurricane
that brought Category 3 winds and
impacts to coastal portions of Gulf
Shores, Alabama with Category 2
conditions experienced elsewhere in
this city.
Category Four Hurricane: Sustained
Winds 131-155 mph (114-135 kt or
210-249 km/hr).
Catastrophic damage will occur.
There is a very high risk of injury
or death to people, livestock, and
pets due to flying and falling
debris. Nearly all older (pre-1994)
mobile homes will be destroyed. A
high percentage of newer mobile
homes also will be destroyed. Poorly
constructed homes can sustain
complete collapse of all walls as
well as the loss of the roof
structure. Well-built homes also can
sustain severe damage with loss of
most of the roof structure and/or
some exterior walls. Extensive
damage to roof coverings, windows,
and doors will occur. Large amounts
of windborne debris will be lofted
into the air. Windborne debris
damage will break most unprotected
windows and penetrate some protected
windows. There will be a high
percentage of structural damage to
the top floors of apartment
buildings. Steel frames in older
industrial buildings can collapse.
There will be a high percentage of
collapse to older unreinforced
masonry buildings. Most windows will
be blown out of high-rise buildings
resulting in falling glass, which
will pose a threat for days to weeks
after the storm. Nearly all
commercial signage, fences, and
canopies will be destroyed. Most
trees will be snapped or uprooted
and power poles downed. Fallen trees
and power poles will isolate
residential areas. Power outages
will last for weeks to possibly
months. Long-term water shortages
will increase human suffering. Most
of the area will be uninhabitable
for weeks or months. Hurricane
Charley (2004) is an example of a
hurricane that brought Category 4
winds and impacts to coastal
portions of Punta Gorda, Florida
with Category 3 conditions
experienced elsewhere in the city.
Category Five Hurricane: Sustained
Winds greater than 155 mph (greater
than 135 kt or 249 km/hr).
Catastrophic damage will occur.
People, livestock, and pets are at
very high risk of injury or death
from flying or falling debris, even
if indoors in mobile homes or framed
homes. Almost complete destruction
of all mobile homes will occur,
regardless of age or construction. A
high percentage of frame homes will
be destroyed, with total roof
failure and wall collapse. Extensive
damage to roof covers, windows, and
doors will occur. Large amounts of
windborne debris will be lofted into
the air. Windborne debris damage
will occur to nearly all unprotected
windows and many protected windows.
Significant damage to wood roof
commercial buildings will occur due
to loss of roof sheathing. Complete
collapse of many older metal
buildings can occur. Most
unreinforced masonry walls will fail
which can lead to the collapse of
the buildings. A high percentage of
industrial buildings and low-rise
apartment buildings will be
destroyed. Nearly all windows will
be blown out of high-rise buildings
resulting in falling glass, which
will pose a threat for days to weeks
after the storm. Nearly all
commercial signage, fences, and
canopies will be destroyed. Nearly
all trees will be snapped or
uprooted and power poles downed.
Fallen trees and power poles will
isolate residential areas. Power
outages will last for weeks to
possibly months. Long-term water
shortages will increase human
suffering. Most of the area will be
uninhabitable for weeks or months.
Hurricane Andrew (1992) is an
example of a hurricane that brought
Category 5 winds and impacts to
coastal portions of Cutler Ridge,
Florida with Category 4 conditions
experienced elsewhere in south
Miami-Dade County.
2010 Tropical Cyclone
Tracks
2010 Atlantic Basin
Tropical Cyclone Names
|
Alex
|
Bonnie
|
Colin
|
Danielle
|
Earl
|
|
Fiona
|
Gaston
|
Hermine
|
Igor
|
Julia
|
|
Karl
|
Lisa
|
Matthew
|
Nicole
|
Otto
|
|
Paula
|
Richard
|
Shary
|
Tomas
|
Virginie
|
|
Walter
|
|
|
|
|
|
|
|