What part do the cyclones play in the reason of advancing south west monsoon? Under what conditions can the Northern plains get a fair amount of rainfall ? When do they receive floods?
Answers
Actually,weak vertical wind shear of horizontal winds is one of the necessary condition to form a cyclone over the sea surface. But the Southwest monsoon is characterized by the strong westerly winds in the lower troposphere below 5 km and very strong easterly winds in the upper troposphere above 9 km and the resulting the strong vertical (wind shear winds shares refers to the change in speed wind speed or direction with respect to height in the atmosphere) will form and it inhibit cyclone development. The potential zone for the development of cyclones shift to the north Bay of Bengal during this season. So due to the presence of strong vertical wind shear between upper and lower troposphere during the Southwest monsoon season, the frequency of tropical cyclones during the Southwest (June to September)monsoon season is very less .