Southeast Coastal Ocean Report
1
Section 1.
Atmospheric Characteristics
Contributed by Francisco Werner (University of North Carolina, Chapel Hill)
The atmospheric characteristics of the southeast coastal ocean (the SEACOOS domain)
are summarized. Elements of the review include a description of the seasonal transitions
in the wind field, and severe storms including winter cold air outbreaks and hurricanes.
Seasonal Patterns in the Wind Field
Five seasonal wind regimes have been associated with the South Atlantic Bight and East
Florida Shelf regions (Weber and Blanton, 1980; Journal of Physical Oceanography,
10:1256-1263); see Figure 1.1 herein.
· Winter (November to February/March): winds are persistently southeastward in
North Carolina and turn more southward over Florida;
· Spring transition (March to May): winds shift to westward from Florida to South
Carolina, with the winds elsewhere in the region being more variable;
· Summer (June and July): westward winds dominate the southern reaches of the
domain, and northward flow sets in for the central to northern portions of the SAB
(Georgia to North Carolina);
· Fall (August): the summer wind patterns break down and become generally
disorganized except for Floridas westward and southwestward winds; and,
· Mariners fall (September and October): southwestward winds (at times
strong) occur over the domain, with westward winds at times over Florida.
Winter Cold Air Outbreaks (winter extra-tropical cyclones)
During the winter months, extratropical cyclones often travel across the southeastern
states and out over the Atlantic Ocean and are known for the devastating weather they
sometimes bring. These storms frequently produce ice, heavy snow and gale force winds
which can cause property damage and loss of life. Perhaps the most infamous of these
cold air outbreaks contributed to the tragic loss of the space shuttle Challenger in January
of 1986. Coincidentally, also in 1986, the Genesis of Atlantic Lows Experiment
(GALE) investigated these storms and their effect on the SE coastal ocean (JGR, Volume
94, number C8, 1989). Figure (1.2) provides snapshots of the atmospheric winds and
pressure for a more recent (March 2001) storm that passed through the southeastern
region. This storm, and another one in the same month, are the subject of a SEACOOS
hindcast modeling paper by He et al (in preparation).