Theta-e, omega and lapse rate cross-section
Notes:
This 12 hour NAM forecast cross-section taken from east to west across the trough shows upward vertical motion focusing just ahead of a cold front aloft, which was directly above the surface trough. A secondary, minor maxima of lift was also associated with the surface cold front farther to the west. The low-levels near the trough and surface cold front were characterized by steep low-level lapse rates (negative low-level lapse rates shaded).
Slide 6