Comments
The South-West monsoon has returned a surplus of 10 per cent on its last day, with a depression drenching Gujarat and a lesser endowed cyclonic circulation wiping out the rain deficit in Uttar Pradesh and Bihar.
That leaves only Haryana-Chandigarh-Delhi with any significant deficit (42 per cent), followed at some distance by West Uttar Pradesh (27 per cent); Nagaland-Manipur-Mizoram-Tripura (22 per cent); and the plains of Bengal (20 per cent).
Positive IOD role
The monsoon had a poor outing in June, and fared only slightly better in July but came back strongly in August and September, riding the twin advantage of a positive phase of the Indian Ocean Dipole (IOD) and a benign tropical Pacific.
The positive phase of the IOD sees the western basin of the Indian Ocean warm up relative to the East, which is beneficial for a concurrent monsoon. The Pacific was found to oblige by turning in only weak El Nino conditions.
The play of the positive IOD in the monsoon scheme of things was evident in the manner in which it swamped Central India even while North-West India and the South Peninsula went on to make considerable gains.
The latest rain driving feature over land is a rare depression that developed early on Monday morning and moved 110 km northwest of Ahmedabad (Gujarat) and 90 km southwest of Deesa (Gujarat) by the afternoon.
It should maintain the intensity of a depression for Monday night, continue to move East-North-East and weaken as a well-marked low-pressure area by Tuesday afternoon while pouring down its contents along the way. Slow-moving systems such as this — it does not really matter whether it is a conventional ‘low’ or has intensified twice over to become a depression — can drop sustained heavy rain under their footprint, creating flooding conditions.
The IMD has forecast fairly widespread to widespread rainfall with isolated heavy to very heavy and extremely heavy falls very likely over Saurashtra, Kutch, North Gujarat and South-East Rajasthan into Tuesday. Scattered to fairly widespread rainfall with isolated heavy falls has also been forecast over West Rajasthan during this period.
East India flooded
Towards the East, a cyclonic circulation in combination with a trough it was linked to, was principally responsible for setting massive floods over Bihar over the past three days. The circulation persisted over South-East Uttar Pradesh on Monday while the trough extended from a counterpart circulation over Punjab and ran further East-South-West to South Assam.
Comments
COMMENT NOW
Comments
Comments have to be in English, and in full sentences. They cannot be abusive or personal. Please abide by our community guidelines for posting your comments.
We have migrated to a new commenting platform. If you are already a registered user of TheHindu Businessline and logged in, you may continue to engage with our articles. If you do not have an account please register and login to post comments. Users can access their older comments by logging into their accounts on Vuukle.