A pulse of the Madden–Julian Oscillation (MJO) has strengthened and moved into the West Indian Ocean setting up lower pressure, clouds and moisture off the Kerala coast and just across the peninsular tip into the waters of the South-West Bay of Bengal off the Tamil Nadu and Sri Lanka coasts.
Over land, intense clouding promising heavy rain is located over Allahabad-Jhansi-Lucknow-Jabalpur belt across East Uttar Pradesh and adjoining East Madhya Pradesh, satellite pictures from this (Wednesday) morning revealed. Less intense clouds are seen spread out over the South Peninsula.
MJO wave arrives in style
The Australian Bureau of Meteorology as well as the Climate Prediction Centre of the US attested to the presence of the MJO pulse over West Indian Ocean (spilling over to South-East Arabian Sea). Dynamical model MJO index forecasts depict a slowdown of the signal’s eastward propagation during August 11-17 across the Indian Ocean with some enhancement of amplitude along the way.
The US agency cited both the European Centre for Medium-Range Weather Forecasts and the Global Ensemble Forecast System suggesting a resumption of eastward propagation of the wave across the Indian Ocean during August 18-24, indicating a longer stay of the MJO signal over these waters.
Rains for Tamil Nadu, Kerala
India Meteorological Department (IMD) sees scattered to fairly widespread rainfall over Tamil Nadu and Kerala during the next five days with isolated heavy falls over Tamil Nadu during next five days and over Kerala until Thursday.
The ECMWF-IFS-HRES model of the European Centre indicates a scenario where three independent rain fronts grow along the West Coast and South Peninsula as well as over East India and extending a ‘limb’ along the East Coast to be met by a third one being piloted from a crucible of activity that has already started to build traction to the south-west of Andaman and Nicobar Islands.
Flourish of rains to East
The two on the eastern side (East India, East Coast and the Bay of Bengal south-west of Andaman and Nicobar) are forecast to meet on the eastern seaboard culminating in a flourish of rainfall which is shown as extending to Maharashtra and parts of Central India from August 17.
This is as much evident from an extended outlook during August 16-18 from the IMD which said that fairly widespread to widespread rainfall may continue over Northeast and East India, northern parts of Uttar Pradesh, the West Coast and over parts of the South Peninsula.
Isolated heavy falls are likely to continue over North-East and East India. Isolated to scattered rainfall is forecast over the rest of the country except over Rajasthan. Rainfall activity is very likely to increase over Odisha, Coastal Andhra Pradesh, Telangana, Vidarbha and Chhattisgarh during this period.
Monsoon trough over land
On Wednesday morning, the IMD said that the eastern end of the rain-causing trough over land continues to run close to the foothills of the Himalayas while the western end lies north of its normal position, weakening rains over North-West India and Central India.
The IMD has therefore forecast subdued rainfall over the rest parts of plains of Northwest India (Punjab, Haryana, Rajasthan), adjoining Central India and most parts of Peninsular India (outside Tamil Nadu and Kerala) including Maharashtra and Gujarat.
Productive cyclonic circulation
A persisting cyclonic circulation over Bihar lying close to the trough will continue to cause fairly widespread to widespread rainfall with isolated heavy to very heavy falls over Northeast India and plains of West Bengal and Sikkim during the next five days. Isolated extremely heavy falls are likely over Assam and Meghalaya during from Wednesday to Friday, the IMD said.
Also read: Indian and US bodies ink deal to improve weather and monsoon forecasts
Fairly widespread to widespread rainfall with isolated heavy falls may continue over East Uttar Pradesh, Bihar, Jharkhand and Gangetic West Bengal during the next 4-5 days. Isolated very heavy falls over Bihar are likely on Wednesday and Thursday. Fairly widespread to widespread rain with isolated heavy falls is likely over Uttarakhand and Himachal Pradesh during most of these days.