A Numerical Modeling Study to Investigate the Role of
Kelvin-Helmholtz Instability on Convection Near the Cape
Canaveral Sea Breeze Front
P. Anil Rao and Henry E. Fuelberg
Department of Meteorology, Florida State University
Department of Meteorology
Florida State University
Tallahassee, FL 32306-4520
(850) 644-6989
(850) 644-9642
rao@met.fsu.edu
Results from a high resolution three-dimensional simulation of the Cape Canaveral sea
breeze are presented. The Advanced Regional Prediction System (ARPS) is run in a two-way
nested mode with horizontal resolutions of 1.6 km, 400 and 100 m. When results are compared
to both observations and theory, the sea breeze structure and associated mesoscale convective
processes are found to be modeled well by ARPS. Kelvin-Helmholtz instability, evident as
billows or vorticies, is seen to initiate at the head of the sea breeze and propagate backwards
relative to the front. These features are most intense in areas of greatest vertical wind shear.
Furthermore, they are evident only on the 100 m grid, thus confirming previous results
indicating the high resolution that is necessary for resolving Kelvin-Helmholtz instability.
Surface convergence along the sea breeze front creates several areas of convection at the frontal
boundary. It is shown that in the region of greatest vertical wind shear, the cells re-intensify
as they move over the sea breeze head. The updraft portions of Kelvin-Helmholtz billows are
shown to be a major source of lift behind the sea breeze head in these convective regions. The
cells then propagate backwards relative to the front along the boundary layer shear vector.