Consider the following statements regarding precipitation and rainfall types in India:

1. Convectional rainfall occurs in parts of central and eastern India during summer, leading to localized thunderstorms that contribute significantly to annual rainfall.

2. Orographic rainfall is the primary reason for heavy rainfall in the Western Ghats and the northeastern states like Meghalaya.

3. Cyclonic rainfall in India is caused only by tropical cyclones, while mid-latitude disturbances do not contribute to precipitation.

4. The northeast monsoon primarily affects Tamil Nadu, bringing significant rainfall during the post-monsoon period.

How many of the above statements are correct?