|The Meteorological and Oceanographic
forecasting factors in the Mid-Atlantic States
and their effects as they relate to
sea shore and inland forest geography
The traditional Mid-Atlantic States comprise the most densely-populated of the nine U.S. regions, and anchor
the megalopolis which runs from Boston to Washington, D.C.. However, many people consider the Mid-Atlantic
to be the states south of the Northeast, centered in Delaware, Maryland, and Virginia . The cities
included New York City on the Hudson River, Philadelphia on the Delaware River, and Baltimore on
the Chesapeake Bay. Diverse and complex natural processes continually change coasts physically,
chemically, and biologically, at scales that range from microscopic (grains of sand) to global
(changes in sea level). Human activity adds yet another dimension to coastal change by
modifying and disturbing, both directly and indirectly, the coastal environments and the
natural processes of change. Storms cause deep erosion in one area and leave thick
over wash deposits in another. Plants retain sediment in wetlands and impede movement
of coastal dunes. Natural processes that change the water level also affect coastal
dynamics. The inland forest has a huge impact on winds and rain runoff into drainage basins.
The prevailing winds in the forests and along the coast produce winds at oblique angles. Even the slightest
angle between the land and the waves will create currents that transport sediment along the shore. Tides
help determine where the waves break, therefore, where sand is deposited and removed. Rip tides occur
along most beaches and can move significant amounts of sand offshore. Storm systems along coasts
contain high winds, create large waves, and cause storm surges that raise water levels as much as
7 meters above normal, carry sand seaward, forming offshore bars; much of this sand migrates
landward during calm weather. The Mid-Atlantic seaboard, for example, hurricanes occur in
the late summer and early fall, and storms are especially frequent during the winter months. Winter
"eroding" beach and the summer "building" beach that is most common along parts of
the west coast.
Predominantly closed bodies of water such as lakes in the inland forest areas experience dramatic water-level
changes in response to precipitation, spring snowmelt, evaporation and human clearing of forest and
the changing of slopes around it. The change in rivers that feed into the lakes also changes the
available moisture available from summer time storms as they develop over lakes. Prolonged periods
of wet weather or dry weather will a dramatic effect on precipitation forecasts for the
Mid-Atlantic States in the future with the continued development and urbanization of the
coastal and inland forest areas. Other local changes in water level occur when the land
either rises or falls relative to the water table with draining of lakes faster than the
water is replenished naturally.
During the last ice age, 26,000 years ago, vast quantities of sea water was changed into glaciers, resulting
in a sizeable drop in the sea level. As we emerge from ice age levels, and sea level has been rising slowly
by millimeters continuously; during the past century. These will eventually change the forecast
parameters for the effects on precipitable water available for precipitation events and the net
affect will be that the mountainous areas which normally held and slow progress of systems will
begin to have less effect as and the coastal areas become thinner and the difference in the coast
to mountain regions will narrow. The affect will cause systems to dump more water in a smaller
area and increase the flooding potential in areas not normally affected by heavy rain events.
The slope of a coast is critical to determining how water-level changes will be affected and how the vegetation
will stay, not withstanding the clearing of foliage for development. As the foliage is cleared and manmade
structures are erected, will the moisture content available change to a more salt based? If the
Mid-Atlantic States continue to clear trees and change the slopes of near shore communities, that
will change the drainage basins of many areas. With that forecasting floods will become
increasing more difficult. The long standing rule of forecasting thunderstorms and severe
thunderstorms will change, but more important is the effects on those areas that have lost
vegetation and the runoff of water from these storms. Rooted plants flourish along the shores
of bays, estuaries, deltas, and other coastal environments that are protected from the full
fury of pounding waves. Plants stabilize dunes through root networks. They build and maintain
marshes by catching and retaining in their roots the fine sediment carried by the water. Their
natural decay cycle further enriches coastal soils and sediment with decomposing plant matter.
Differences in meteorological and oeanographical effects determine which foliage and sea
plants will thrive in an environment. They are some plants that require total submergence, some
require submergence and aeration, and others flourish except at the highest tides.
Gradual changes in weather patterns caused by the geography of the area, salinity and sea level allow
normal plant succession to occur in protected coastal environments. Abrupt changes in these conditions
often result in widespread destruction of plant communities and the loss of sediment being held by
their roots. The erosion of barrier islands can lead to saltwater intrusion and increased wave action,
which kills plants and destroys the wetlands behind the islands. With this destruction, forecasting
the interaction with storm systems and the ocean will become much more difficult.
Human activities add another layer of complexity to the natural processes of coastal and inland forests. These
will affect sources of new sediment to the coast and the movement of sediment within the coastal environment; they
may promote changes in sea level. To prevent beach loss, groins are often constructed out into the water. These
solid structures impede the littoral drift of sand caused by long shore currents. Seawalls constructed confine
the wave energy and intensify the erosion by concentrating the sediment transport processes in an increasingly
narrow zone. As the beach disappears, it is exposed to the full force of the waves. A seawall built to
protect manmade structures along a coast will result in the complete disappearance of the beach
itself. Off-road vehicles and foot traffic on sand dunes compact sand, destroying plant roots
and animal burrows.
Coasts, as boundaries between land and water, are characterized by the geologic nature of the land, which
is unstable and often fragile, and the dynamic power of wind and sea.
Some points to consider, Coastal erosion at widely varying rates, half of our valuable wetlands have
been lost, Pollution of coastal areas has permanently contaminated ground water in some communities,
hard-mineral resources such as sand and gravel for construction and beach nourishment are no longer
available onshore. An expanding trend of growth and expanded development continue, and if sea-level
rise brought on by potential climate changes also occurs, stress on our coastal environments will
increase. The stewardship of our coastal resources requires balancing human needs and
expectations with coastal realities. The forecasting of precipitation events will have to
change based upon many factors, and the factors influencing their development is critical
in any attempt to lessen the conflicts within computer models and empirical rules we
use now and the natural processes that nature currently uses.
Ignorance and continued disregard of the geologic processes that constantly reshape our coasts are
tragically intensifying the collisions between people and nature. A clear understanding of how coastal
environments have formed and what natural changes they have undergone in the recent geologic past can be
critical in predicting with confidence how we can forecast events in the future.
The Mid-Atlantic region, with its extensive coastline, is likely to suffer from the impacts of increased
flooding and sea-level rise expected under scenarios of climate change. Changes in temperature and
rainfall could take a toll on the regions important deciduous forests and migratory bird habitats
and contribute to summer heat stress and other health risks. The coastal areas and inland forests
are vulnerable to various climate changes; higher average temperatures, higher and lower precipitation
levels, more intense rainfall and flooding.
Recommended actions for protecting against future impacts from sea-level rise and increased flooding
include improving watershed management and reduced development in areas vulnerable to erosion
Although overall forest productivity might increase, a relatively rapid shift in dominant forest
types might foster invasive species and reduce diversity. Younger tree stands could also mean a
decline in the role of forests in preventing erosion and siltation.
The heavily populated Mid-Atlantic region already suffers relatively more heat-related mortality than
other parts of the country. How accurate will the heat stress forecast be with increased warming? Will
there be an increase risk especially for children, the elderly and people lacking access to air conditioning,
safe water supplies. Higher rainfall and floods increase the risks of waterborne diseases like
Cryptosporidiosis. There are many concerns for the preserving of existing forests, wetlands,
and coastal areas, and of cutting the volume of pollutants that flow into the region watersheds and
coastal areas from agricultural production and human settlements and the effects on weather forecasts
now and in the future.
"Census Regions and Divisions of the United States" (English). Retrieved on 2007-11-03. Chabreck, R.A.,
1988, Coastal marshes; ecology and wildlife management
Dolan, Robert, Lins, Harry, and Stewart, John, 1980, Geographical analysis of Fenwick Island,
Maryland, a middle Atlantic coast barrier island
Dolan, Robert, and Lins, Harry, 1986, The Outer Banks of North Carolina
Leatherman, S.P., 1988, Barrier island handbook: College Park, Md.
Committee on Coastal Erosion Zone Management, 1990, Managing coastal erosion
Committee on Engineering Implications of Changes in Relative Mean Sea Level, 1987,
Responding to changes in sea level-Engineering implications: Washington, D.C.King, C.A.M., 1972, Beaches
and coasts (2d ed.
Kaufman, Wallace, and Pilkey, O.H., Jr., 1983, The beaches are moving; the drowning of America's shoreline
Morrison, H.R., and Lee, C.E., 1981, America's Atlantic Isles: Washington, D.C., National Geographic Society
Yasso, W.E., and Hartman, E.M., Jr., 1976, Beach forms and coastal processes
Woods Hole Research Center annual report 25 March, 2004