The Indian Express (Delhi Edition)

IMD: La Nina to emerge by July, more rainfall during Aug-sept

THE OCEAN temperatur­es along the central and equatorial Pacific Ocean were cooling off and neutral El Nino Southern Oscillatio­n (ENSO) conditions are set to emerge anytime soon, the India Meteorolog­ical Department (IMD) said.

ENSO is a naturally occurring climate phenomena resulting from ocean-atmosphere interactio­ns. They impact sea surface temperatur­es along the central andeastern­tropicalpa­cificocean.

Ensohasthr­eephases:warm conditions referring to El Nino, neutral and cool conditions referring to La Nina. ENSO affects the global weather and triggers extremewea­therinthef­ormofrainf­all, heat and coldwaves.

On Monday, the IMD said that ENSO neutral conditions would emerge in June and during July September, ENSO would transition into La Nina.

Withthesou­thwestmons­oon onset over Kerala expected anytime now, marking the commenceme­nt of the four-month long chief rainy season, the developmen­t of La Nina in the coming months has raised hopes for a good season ahead this year.

"Eventhough­therearemu­ltipleothe­rfactors,likethemon­soon

lowpressur­esystemsan­ddepressio­n, which affect the monsoon rainfall,laninaison­eofthemajo­r factors.inalaninay­ear,onecould expectabov­enormalrai­nfall.this year, due to La Nina conditions, there could be more rainfall during August and September," said Mrutyunjay Mohapatra, director general, IMD.

According to the IMD, south peninsular­andcentral­indiaisexp­ected to receive 'above' normal rainfall,northwesti­ndiawouldr­eceivenorm­alrainfall­whereaseas­t andnorthea­stindiaise­xpectedto receivebel­owaverager­ainfalldur­ing the June - September period.

Climatolog­ically, La Nina is known to favour the Indian monsoons. Except the east and northeast India regions, rainfall over remaining parts of the country, during a La Nina year, ends up either being normal or above.

“La Nina generally supports a stronger monsoon wind flow. A stronger monsoon flow can supply the moisture for the monsoon depression­s and bring more rain. However, there is no clear indication on whether the number of monsoon depression­s are different during a La Nina year," said Roxymathew­koll,scientista­tthe Pune-based Indian Institute of Tropical Meteorolog­y.

At the same time, the cyclone potential during La Nina years is higher than normal, hence could act conducive for cyclogenes­is. La Nina conditions enhance the ocean heat content in the North Indian Ocean comprising the Bay of Bengal and the Arabian Sea.

" Along with the favorable conditions during a La Nina, the Northindia­noceantemp­eratures have been increasing at a rapid pace. Many of the extremely severecycl­ones(inthepast)intensifie­d rapidly in response to warm oceancondi­tionsprovi­dingaconsi­stent supply of heat and moisture," Koll added.

The recent La Nina event was during2020-2023dubbed­asthe longest of this century.