on December 29, 1997 at 09:27:23:
Initial cloud development and consequently deeper convection along
a boundary is generated and organized by the boundaryís interaction
with turbulent structures in the boundary layer, commonly horizontal
convective rolls. Clouds will form at the intersection points of
the boundary with the turbulent structures.
Recent studies (e.g., Wilson et al. 1992; Wakimoto and Atkins 1994;
Atkins et al. 1997) have shown that clouds are initiated at preferred
locations along boundary layer convergence zones. These preferred
locations are also where boundary layer turbulent structures such
as horizontal convective rolls intersect the boundary. Atkins et
al. (1995) performed detailed dual-Doppler analysis along a sea-breeze
front and showed that the intersection points of the sea-breeze
with horizontal convective rolls were locations of vertical velocity
maxima along the front. Close to the front, the horizontal convective
roll axes were tilted upward and lifted by the frontal updrafts,
creating a deeper and stronger updraft at the intersection point.
Further observations of many different types of boundaries are required
to assess the generality of the aforementioned results.
Atkins, N.T., R.M. Wakimoto, and T.M. Weckwerth, 1995: Observations
of the sea-breeze front during CaPE. Part II: Dual-Doppler and aircraft
analysis. Mon. Wea. Rev., 123, 944-969.
Atkins, N.T., R.M. Wakimoto, and C.L. Ziegler, 1997: Observations
of the fine-scale structure of a dryline during VORTEX 95. Mon.
Wea. Rev., In Press.
Wakimoto, R.M., and N.T. Atkins, 1994: Observations of the sea-breeze
front during CaPE. Part I: Single-Doppler, satellite and cloud photogrammetry
analysis. Mon. Wea. Rev., 122, 1092-1114.
Wilson, J.W., G.B. Foote, N.A. Crook, J.C. Fankhauser, C.G. Wade,
J.D. Tuttle, C.K. Mueller, and S.K. Krueger, 1992: The role of boundary-layer
convergence zones and horizontal rolls in the initiation of thunderstorms:
A case study. Mon. Wea. Rev., 120, 1785-1815.