India Meteorological Department (IMD) announced on Friday that the Southwest monsoon has withdrawn from many parts of West Rajasthan.
The withdrawal process has been in the making for some time with the skies over Rajasthan and large parts of northwest India clearing up and the mercury consistently peaking to beyond the 40 deg Celsius.
ANTI-CYCLONE
On Friday, weather charts showed the large anti-cyclone (high-pressure area within sinking motion of air that retards cloud formation) sneaking in from across the northwest border.
The withdrawal line passed through Ganganagar, Churu, Jodhpur and Barmer. The monsoon is likely to withdraw from more parts of northwest India during the next four days in fairly fast progression.
The process could get bogged down just over central India as easterly flows from a lately activated Bay of Bengal fill large parts of peninsula and even parts of central India.
The anticipated low-pressure area is expected to materialise over the Bay by Sunday even as a much stronger system is forecast to brew over the South China Sea concurrently.
The Bay system would be forced to let go of some moisture that would feed into the stronger South China Sea system, according to the European Centre for Medium-Range Weather Forecasts (ECMWF).
After walloping the Indo- China coast for a landfall, the South China Sea system could yet again set the Bay on fire, with ECMWF projecting the formation of another `low' during early October.
In this manner, the withdrawal process of the monsoon from the rest of the mainland India may get affected indefinitely.
THUNDERSHOWERS
The US National Centres for Environmental Prediction sees the whole of the peninsula and parts of central India being brought under the cover of thundershower activity until October 11, according to as per latest forecasts.
Monsoon withdrawal has already been delayed by more than 20 days owing to occasional presence of cyclonic circulations and troughs transported in by the westerly flows across northwest India.
But on Friday, towards the southeast, an upper air cyclonic circulation lay in wait over northwest and adjoining west-central Bay of Bengal, an IMD update said.
Under its influence, the anticipated low-pressure area is likely to form during the next two days over west-central Bay of Bengal and neighbourhood.
Scattered rainfall activity has been forecast over the Northeastern States during the next three days before tapering off.
Fairly widespread rainfall activity with isolated heavy fall is likely over peninsular India, including Maharashtra, for five days from Saturday, the IMD update said.
WIDESPREAD RAINS
Satellite pictures showed convective clouds over parts of southeast and west-central Bay of Bengal and the Andaman Sea.
Forecast for the three days ending September 30 said that scattered to fairly widespread rainfall activity with isolated heavy falls is likely over the west coast and peninsular India.
An update from the Chennai Met Centre said that the monsoon has been vigorous over Karnataka during the 24 hours endeding Friday morning.
Rainfall occurred at most places over Karnataka and at a few places over Kerala. Isolated rainfall occurred over Tamil Nadu and Andhra Pradesh.
Forecast for the next two days said that rain or thundershowers are likely to occur at most places over Karnataka; at many places over coastal Andhra Pradesh and at a few places over Kerala, Lakshadweep, Telangana and Rayalaseema.
Isolated rain or thundershowers has been forecast over Tamil Nadu and Puducherry.
A warning valid for the next two days said that isolated heavy rain is likely over coastal Karnataka and the ghat areas of south interior Karnataka.