Slide 15 of 29
Notes:
On the plan view, this is a plot of the boundary layer winds (barbs/KT), areas of convergence (red) and divergence (blue). Note the area of low level convergence that envelops the northern portions of this wave, along and on both sides of the axis on areas north of 17N. The strongest convergence however concentrates on the center of the trough and to the north-northeast of this perturbation.