According to Skymet Meteorology Division in India, country is on the verge of entering the pre-monsoon season but these showers can be considered as precursor to the pre-monsoon season. Though there is no specific date but pre-monsoon showers generally commences from mid-March.
Peninsular India starts heating up by March and with heat, thunderstorm activities also come up. Invariably peninsular India observes a peak pre monsoon rainfall which could be a precursor and decisive for the likely onset dates of Southwest Monsoon. The intensity and spread of rainfall during this time is reflective of the performance of the coming monsoon season.
Currently, a low level cyclonic circulation over northern parts of Karnataka along with a trough extending southwards has given light to moderate rain over parts of Tamil Nadu and Kerala. Moreover, confluence of southeasterly winds from Tamil Nadu and northerlies along the Kerala coast has enhanced the rain activity.
In a span of last 24 hours, Erode in Tamil Nadu recorded 50 mm of rain, Karur Paramathi 47.4 mm, Dharmapuri 28 mm, Valparai 29 mm, Periyar 20 mm and Hosur 20 mm. In Kerala, Thodupuzha received 38.5 mm, Nedumangad 32.2 mm, Kottayam 10.6 mm, Kanjirappally 5.8 mm, Punalur 0.2 mm and Thiruvananthapuram observed just trace.
The system is expected to cause rain for next 48 hours and with the gradual shift towards southwards, the rain belt will also shift its focus over Kerala.
As we proceed further, frequency of such systems will also increase.