Why east faces more storms?It is a well known climatological fact that during pre-monsoon and post-monsoon seasons in the North Indian Ocean, more cyclones form in the Bay of Bengal compared with the Arabian Sea.1) Subtle differences between the way that convective currents behave over the Arabian Sea and over the Bay of Bengal may explain this higher frequency of cyclones forming over the Bay.There is a large-scale downward wind movement over the Arabian Sea during most of the year and convection has little chance to grow and intensify into cyclones.2) of the Bays high fertility -its more continental (surrounded by land) compared to Arabian Sea. Therefore, it is warmer and prone to low pressure zones-The westward wind flow direction in areas north of a cyclone in the Bay contributes to storm surges -- an abrupt rise in the sea level, mimicking conditions of a mini tsunami -- and significant water movement towards land.3) the east coasts flatlands.-more river deltas and thus moisture content on eastern ghats.4) E. Ghats unlike western ghats are in interiors and that too broken. The plains of "northern circars" offer almost no-resistance to the cyclones. This increases their impact to a great extent.The situation is different on the west coast where the high western ghats are close to the coast -- the entire chain of mountains within 100km from the coast. The western ghats is a strong barrier to winds.

Arabian Sea: why more cyclones in some yearsThis is due to a newly discovered Phenomenon (2007) El Nino Modoki which causes warm moist conditions in the Central Pacific and dry cold conditions in Eastern and western pacific. A more familiar phenomenon, El Nino, was found to suppress cyclone formation in the Arabian Sea.The reason why El Nino Modoki brings only fewer number of cyclones in the Bay of Bengal is because one of the two descending limbs of the Walker Cell is over the western Pacific and Bay of Bengal. The descending limb causes dry conditions not conducive for cyclone formation. The ascending limb of the Walker Cell, on the other hand, brings rain. Also, an El Nino Modoki creates stronger divergence over the western Pacific and Bay of Bengal compared to El Nino. Divergence (opposite of convergence) means surface winds move away from each other and result in low relative vorticity (rotational flow of winds). These conditions are not conducive for cyclones. This explains why Bay of Bengal region (close to western Pacific) has fewer cyclones during an El Nino Modoki.On the other hand, there is large convergence over the Arabian Sea during an El Nino Modoki explaining the large number of cyclones in that region. A statistical analysis of the El Nino and El Nino Modoki years between 1979-2004 was conducted. It was found that there were four El Nino years and seven El Nino Modoki years during this period.The number of cyclones per year show significant differences indicating that El Nino Modoki years are conducive for cyclone formation over Arabian Sea while El Nino is conducive for cyclones over the Bay of Bengal.Cyclones usually do not form during monsoon season,.Why?1) Atmospheric parameters low-level relative vorticity, mid-tropospheric relative humidity, vertical wind shear are not at values conducive for cyclone formation during monsoon.2) Second, during monsoon there is strong zonal (latitudinal) wind in the form of a jet at lower levels and this is not conducive for cyclone formation as the vertical shear between lower and upper troposphere will not be minimum..3) Finally, the sea surface temperatures are too low for cyclogenesis.