There are two cyclonic circulations over the Bay of Bengal (BoB). One circulation is marked over Northwest and adjoining West-Central BoB. The other circulation is lying over the South Arakan Coast of Myanmar and neighbouring BoB. The latter is the remnant of tropical depression ‘Soulik’ from the South China Sea, which, on the expected lines, is evolving over Northeast BoB.
Both these circulations are likely to merge and under their combined influence, a low-pressure area is expected to form over Northwest and adjoining West-Central BoB, within the next 24 hours. As it happens during the fag end of monsoon in the month of September, this will not be a very strong weather system. But, it is likely to be a slow-moving low-pressure, after it crosses over land. Therefore, it is likely to spend a fair amount of time, while moving across the central parts of the country. Active monsoon conditions over most of these parts and possibly vigorous in some pockets, are likely during this week.
There is an east-west oriented shear zone, roughly along 20°N, from the coast of Odisha to the Konkan region. As the low pressure is likely to track along the axis of the shear zone, the weather activity will get compounded under the combined influence of the two systems. The joint effect will slow down the movement and the monsoon activity will remain a dominant feature over the central parts, during this week.
Over the next two days, on the 23rd and 24th, two different pockets on the opposite ends of the shear axis will have weather activity. On the eastern side, South Odisha, North Coastal Andhra Pradesh and South Chhattisgarh will have fairly widespread, moderate rain and thundershowers. The spread and intensity will be more on the other end covering Marathwada, Madhya Maharashtra, Konkan and South Coastal Gujarat. On the subsequent two days, the extent and scale of weather activity will accentuate further to simultaneously reach parts of Madhya Pradesh, Maharashtra, Gujarat and South Rajasthan. Konkan Coast is likely to come in for some heavy weather activity. There is a likelihood of a northward latitudinal shift of weather activity to reach and cover parts of Bihar, Jharkhand, Uttar Pradesh and North Madhya Pradesh. During the last three days, between the 26th and 28th of September, most parts of Gujarat, especially the South Coastal region and Saurashtra will experience heavy to very rains, triggering alarming conditions in some pockets. Border areas of South Rajasthan also will need to exercise caution to avert inclement weather activity, as well.
Image Courtesy: The Statesman