The role of the jet stream/streaks in cyclone development

• Jet streaks (wind maximum in jet stream) tend to be found in base of trough
• Convergence of air occurs in the entrance region and is maximized on the left side (point C)
• Divergence of air occurs in the exit region and is maximized on the left side (point D)

• So, you want point D directly over the surface low removing air from the surface low
• Point C should be directly over the surface high supplying air to the surface high