The India Meteorological Department (IMD) has said the South-West monsoon has entered parts of South-East Bay of Bengal, Nicobar Islands and the South Andaman Sea on Friday, around the normal date. The northern limit of the monsoon, signifying its farthest line of coverage, has passed through Nancowry. Conditions are favourable for its further advance into some more parts of the South Bay of Bengal, the Andaman Sea and the Andaman & Nicobar Islands during the next 3-4 days.

Helpful cyclonic circulation 

Satellite pictures on Friday morning showed a cyclonic circulation posited off the Indonesian coast, powering the cross-equatorial flows and clouds in the extreme South-East parts of the Bay. Elsewhere in the Indian Ocean, cyclone Fabien to the South of the Equator, had achieved the speed and intensity of a major hurricane but has since started showing signs of weakening. 

It is forecast to move away from Diego Garcia and head towards Madagascar. It may fizzle out just short of Madagascar. As long as it is alive, it may not allow monsoon flows into the Arabian Sea to strengthen. Already in the Arabian Sea, an unfriendly region of high pressure (anti-cyclone) has emerged at the lower levels, which will stay anchored till the end of the month. 

Also read: Can India tame the impending El Niño?

Western disturbances

Parts of the West Coast, East-Central India and adjoining North-West India may witness rain or thundershowers over the next few days, as western disturbances move and set up troughs extending into the southern parts of the country. Rain or thundershowers are already active over the West Coast, and may become better organised over the next three to four days. The US National Centres for Environmental Prediction agreed, suggesting rain from western disturbances around the time of onset of the monsoon, may be mistaken for the actual onset, which is forecast to be slightly delayed this year. 

On Friday morning, the IMD located an incoming western disturbance preparing to enter West Rajasthan. Cyclonic circulations lay over Punjab and adjoining Central Pakistan; South Pakistan and adjoining South-West Rajasthan; and over East Uttar Pradesh. A trough runs from the cyclonic circulation over East Uttar Pradesh to Telangana. 

Also read: BL Explainer. Does the delayed arrival of the South-West monsoon matter?

Heat-busting dust storms

A short-term weather outlook said dust storms or dust raising winds may lash isolated pockets over Rajasthan on Monday and Tuesday, which may help reduce the heat. Over to Central India, light to moderate isolated light rain, thunderstorms, lightning and gusty winds are predicted for Madhya Pradesh, Vidarbha and Chhattisgarh on these days. As for the South, light to moderate to isolated light rain, thunderstorms, lightning and gusty winds are forecast for most parts during next five days. 

Heat wave conditions may prevail over parts of South Uttar Pradesh, West Rajasthan and North Madhya Pradesh from tomorrow (Saturday) to Tuesday. Humid air and high temperatures may set off hot and discomforting weather over Bihar, Jharkhand, Odisha and Konkan and Goa during the next five days, and over Coastal Andhra Pradesh, Rayalaseema, Kerala and Tamil Nadu until Tuesday.