The weather Next Week
What is a trough?
Troughs and Ridges deal with things like geopotential heights, Vorticity Advection, Temperature Advection. These are very complex and deal with a lot of physics, differential geometry and complicated math equations. I will try to keep the math and science out of the discussion .
Likewise, a trough is a region of lower pressure without being exactly a center of it. The difference is that, spin counter-clockwise along a trough, the air doesn't (in the northern hemisphere) but rather, influenced by the nearby clockwise motion of the surrounding high pressures.