The weather-setting low-pressure area over North Odisha weakened on Friday, providing respite from the heavy rain spell experienced over parts of Central and South Peninsular India during the last few days. The backbone monsoon trough persists over the plains of North India, but indications are that it would start moving further to the northern parts of the country sooner than later.
Secondary trough appears
A harbinger of the expected weak monsoon conditions was evident on Friday in the form of a secondary trough straddling East India, from the cyclonic circulation over Odisha to West Assam. A proper monsoon does not brook such secondary trough formations around the main trough. The India Meteorological Department (IMD) said light to moderate to fairly widespread to widespread rain with isolated heavy rain may persist over Central India.
Parts of West India may also see heavy rain over Konkan, Goa and the ghat areas of Madhya Maharashtra during the next five days, before the expected ‘break phase’ sets in slowly but surely. Monsoon activity over the West Coast, too, will switch off to likely signal a classic ‘break phase.’
Lull over South India
South Peninsular India will enter a lull phase from Saturday, while rain activity shifts to parts of East India and North-East India. The rains will gradually spread further to the foothills of the Himalayas across Bihar, Uttar Pradesh and Uttarakhand, and the adjoining plains from August 3/4. Incoming western disturbances may intensify rain activity from time to time.
The break in the monsoon phase could not have come at a better time, with the all-India rain surplus reading at seven per cent, with only three more days to bring July, the rainiest month, to a close. As many as 30 of the 36 meteorological sub-divisions have so far received normal to above-normal rainfall.
Rain surplus at 7 per cent
Of the remaining six, five are in the East and North-East India, and one (Kerala) in South India. The deficit is highest in Bihar (-49 per cent), followed by Jharkhand (-48 per cent); West Bengal (-40 per cent); East Uttar Pradesh (-35 per cent); Kerala (-32 per cent); and Nagaland-Manipur-Mizoram-Tripura (-31 per cent).
Incidentally, the break phase will bring the monsoon trough closer to the foothills along the North and East, bringing badly-needed though delayed rain to all the deficit regions listed above, except Kerala in the South. Global models indicate it will be until the end of August, when the rain can return to South Peninsular India in the next possible spell that may last until September 5, as per current estimates.