Geographical Location – Andhra Pradesh has a vast coastline, of about 600 km, starting from 13⁰N and extending up to 19⁰N. This is a large distance and therefore cyclones which form in the Bay, especially during the northeast monsoon, will almost always hit the Andhra coast ((South Andhra or North Andhra), no matter what path they take.
Origination– Low pressure systems which eventually form into a cyclonic storm originate in the regime of the easterlies in the upper tropospheric levels. In simple words, cyclones mostly form over the Andaman Sea or in the Bay of Bengal. As they form, easterlies push them towards the east coast of India, particularly towards Andhra Pradesh, thus affecting the state the maximum.
Threatening Cyclones–Every year in the pre monsoon and post monsoon season, Andhra coast is threatened by so called ‘threatening cyclones’ which seem like they would hit Andhra but actually skirt the coastline and head for Bangladesh instead. Earlier this year in May, Cyclone Mahasen looked like it is headed for Andhra Pradesh but re-curved towards Chittagong in Bangladesh. These ‘threatening cyclones’ might not hit Andhra, but the clouding effects of the cyclones bring good amounts of rain at the Andhra coast, therefore not sparing the state completely.
Some of the worst cyclones that hit Andhra Pradesh in the last few years were Yemyin (2007), Khai-Mhuk (2008), Laila (2010), Nilam (2012) and Phailin (2013).
Current forecasts show, trouble for Andhra Pradesh will continue post Helen as another system in the Andaman Sea may bring more rain.
Photo from wikipedia