Intensifying ‘low’ may scale up monsoon over the North

Active monsoon conditions over North India caused a resident low-pressure area over East Uttar Pradesh to intensify on Tuesday.

The Met Department has said that it could go on to intensify another round and become a monsoon depression — not a regular happening over land — by Wednesday.

Stormy conditions This is expected to set up stormy conditions and heavy to very heavy rain over a good part of Uttar Pradesh, Bihar, Jharkhand and Madhya Pradesh over the next couple of days.

The calibrated strengthening of the rain-driving ‘well-marked’ low-pressure area points to the overall health of the monsoon, though manifest now largely to the north of the country.

It is remarkable that the system did not blink even in face of the ‘pull-effect’ from a comparably well-endowed rival, typhoon Nepartak, raging to the East of the Philippines.

The Indian monsoon takes cues from the concurrent monsoon over the North-west Pacific, part of the world’s largest ocean basin, and enjoys a give-and-take relationship with it.

Pacific typhoon This is most evident during the typhoon (cyclone) season, which typically occurs from July to October, when typhoons have been known to hold sway on monsoon flows to India.

Away-going (headed east-northeast) typhoons, as in the instant case, could hit monsoon flows headed for India while incoming ones send ‘pulses’ into the neighbouring Bay of Bengal, where they grow as ‘lows’ and boost the monsoon here.

The European Centre for Medium-Range Weather Forecasts suspects that the ‘drag’ effect of typhoon Nepartak could delay the formation of the next ‘low’ in the Bay of Bengal.

The US Climate Prediction Centre tends to agree but surmises that moderate rain could be the outcome for the eastern two-thirds of the country (including parts of Central, East and North-West India) between July 11 and 17.

An IMD outlook for Wednesday said that heavy to very heavy rainfall is likely at a few places over east Madhya Pradesh and Chhattisgarh; at isolated places over east Uttar Pradesh, Assam, Meghalaya and coastal Karnataka; heavy at isolated places over west Madhya Pradesh, Vidarbha, Bihar, Jharkhand, West Bengal, Sikkim, Arunachal Pradesh, Nagaland, Manipur, Tripura; Madhya Maharashtra; Konkan, Goa, and Kerala.

A mostly similar forecast is valid for the next four days as well as the depression moves to the west towards Gujarat, raining heavily in the process.

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