Tailend of a Cold Front

A cold front is defined as the leading edge of a cooler mass of air, replacing (at ground level) a warmer mass of air, which lies within a fairly sharp surface trough of low pressure. It forms in the wake of an extratropical cyclone, at the leading edge of its cold air advection pattern, which is also known as the cyclone's dry conveyor belt circulation. Temperature changes across the boundary can be as much as 50F (30C). When enough moisture is present, rain can occur along the boundary. 

ITCZ

 

ITCZ means Inter-Tropical Convergence Zone. It is a region of convergence between the trade wind systems from the southern and northern hemispheres. Causes thunderstorm convection in tropical regions near the equator.

The position of the ITCZ varies with the seasons. In July, over the Atlantic and Pacific, the ITCZ is between 5 and 15 degrees north of the Equator, but further north over the land masses of Africa and Asia. In January, over the Atlantic, the ITCZ sits no further south than the Equator, but extends much further south over South America, Southern Africa, and towards Australia. Over land, the ITCZ tends to follow the sun's zenith point.

When an aircraft fly through the ITCZ, it  might encounter all the hazards associated with Cb clouds such as icing, turbulence, lightning, and wind shear. However, it is in this zone that the most severe effects may often be encountered.