Observations of the Gulf Stream thermocline as it meanders over the co
ntinental slope off Cape Hatteras are presented. Daily vertical sectio
ns of temperature and geostrophic velocity to 1500 m are calculated fr
om an array of inverted echo sounders aligned across the Gulf Stream.
These accompany time series of deep currents from a simultaneous array
of bottom current meters. The vertical sections are computed using a
previously derived technique which assumes the Gulf Stream variability
is primarily first baroclinic mode. The sections reveal that the Gulf
Stream front systematically shoals when it meanders offshore, an effe
ct not observed farther downstream. This is accompanied by a compressi
on of the main thermocline that in turn increases the core velocity of
the jet but has little effect on overall transport. To explain this s
hoaling, the Gulf Stream is treated as a two-layer flow; the lower lay
er vorticity balance suggests that the shoaling is caused by deep wate
r columns preserving their layer thickness in the presence of the stee
p topography.