The sun starts moving in the northern hemisphere after the Vernal Equinox, Significant increase in temperatures marks the commencement of the pre-monsoon season.
Pre-monsoon is from March to May. April is considered the hottest month for the western and southern regions of the country. For North India, May is the hottest month. Temperatures of northwest India sometimes reaches 50°C and higher. With the increase in temperatures in the month of March and April, pre-monsoon activities start increasing.
Now maximums are reaching around 40 degrees over parts of Central India. Due to high temperatures, heat low usually forms over the Central part of the country. Instability in the atmosphere also contributes to the formation of thunder clouds. We expect thunderstorm and thundershowers to commence over many parts of Central India, particularly over Madhya Pradesh, Vidarbha and Marathwada from March 18. By March 19th, parts of East Rajasthan, Chhattisgarh and Madhya Maharashtra will also start receiving rain and thundershower activities. These pre-monsoon activities will be associated with isolated hail storm and strong winds. Between March 21 and 23rd, pre-monsoon activities may also commence over Kerala parts of Tamil Nadu and south Karnataka. Parts of Telangana, Jharkhand, Odisha and Bihar may also witness isolated to scattered rain and thunderstorm during this period.
Intense thunderstorms, known locally as Kal Baisakhi or "Nor'westers", which are commonly associated with hailstorm and very strong winds, are common in east India. Odisha, West Bengal, Assam, Bihar, Chhattisgarh, Jharkhand and North-Eastern states of India are affected by violent thunderstorms. They cause considerable damage to life and property. But these are more common between April and June. Therefore, we do not expect such weather activities in east India during this period.