Finally, monsoon arrives in Kerala, all eyes on its further progress

Vibha Sharma

Chandigarh, June 8

Finally, the Southwest Monsoon today arrived over the Indian mainland, touching Kerala a week later than its normal date of arrivalJune 1.

All eyes are now on its progress further on.

The IMD had said that due to cyclone ‘Biparjoy’, the onset over Kerala would be “mild”.The very severe cyclone ‘Biparjoy’ (pronounced “Biporjoy”) will intensify further gradually during the next 24 hours and move nearly north-northwestwards during thethree days, the weather office has said.

Normally, the much-awaited seasonal rains arrive over Kerala around June 1, enter south Maharashtra around June 7 and cover the state by June 15.

“Monsoon advances northwards, usually in surges, and covers the entire country around July 15. The NLM is the northern most limit of monsoon up to which it has advanced on any given day,” as per the IMD.

Several states facing deficit

According to the data for cumulative rains between June 1 and June 8, several parts of the central, eastern and western parts of the country are facing deep rain deficienciesup to 91% in Chhattisgarh, 85% in Maharashtra, 71% in Madhya Pradesh, 75% in Karnataka and 86 % in Uttar Pradesh.

The delay in the onset has already resulted in water shortage in several parts of rural Maharashtra with villagers depending on tankers and traveling several kilometers to get water, according to some TV channels.

In contrast, northern states are surplus many times over due to back-to-back western disturbances in the region. Himachal Pradesh is surplus by 100%, Rajasthan by 172% and Punjab by whooping 231%.

Tracking monsoon

The earliest the monsoon ever arrived in Kerala was May 11 in 1918 and the most delayed was June 18 in 1972.

Last year it arrived in Kerala on May 29.

The IMD says the date of the monsoon onset over Kerala may vary and also that there is no direct correlation between the delay in the southern state and arrival in other parts, say Delhi. However, delay in Kerala will expectedly affect progress over southern states and Mumbai.

Over the next five days, light/moderate/fairly widespread rainfall with thunderstorm/lightning/gusty winds is very likely over Kerala,Lakshadweep, coastal and south interior Karnataka.

Isolated to scattered activity is also expected over north interior Karnataka, Tamil Nadu and Andhra Pradesh, the IMD says.

Overall, despite the evolving El Nino conditions, India is expected to get normal rainfall during the four month (June-September) sojourn of the monsoon in 2023, or say the weather office has assured regarding the weather phenomenon responsible for bringing rains to close to two-third of India’s agricultural tracts and replenishing ground water and reservoirs critical for drinking water and power generation, basically the overall well-being of people and the country’s economy. 

How is onset declared?

The weather office follows certain guidelines for declaring the onset over Kerala and its further advance.

If after May 10, 60%of 14 stations enlistedMinicoy, Amini, Thiruvananthapuram, Punalur, Kollam, Allapuzha, Kottayam, Kochi, Thrissur, Kozhikode, Thalassery, Kannur, Kudulu and Mangalore report rainfall of 2.5 mm or more for two consecutive days, the onset over Kerala is declared on the second day.

This provided some other criteria are also in concurrence regarding the wind field and Outgoing Longwave Radiation (OLR).