Much awaited first low-pressure area of monsoon 2021 has formed over the northwest Bay of Bengal and adjoining coastal parts of Odisha. It is likely to become more marked and move northwest across Odisha, Chhattisgarh, and Jharkhand in the next 24 hours. The weather system will move very slowly thereafter and may possibly remain stationary for some time over the trijunction of Odisha, Chhattisgarh, and Jharkhand. Vigorous monsoon conditions are expected over eastern and adjacent central parts of the country.
Southwest monsoon has already made an early advance over parts of Chhattisgarh, Odisha, and West Bengal. With the presence and slow movement of this low-pressure area, monsoon is likely to cover before schedule, entire Odisha, West Bengal, Chhattisgarh, Jharkhand, and Bihar in the next 72 hours. Monsoon current may proceed further to reach East Uttar Pradesh and East Madhya Pradesh in the subsequent 48 hours. Southwest monsoon also stands a chance to go beyond and reach the remaining parts of Madhya Pradesh and Uttar Pradesh and sweep the outskirts of Delhi well before stipulated dates.
Due to the persistent presence of the cyclonic circulation of low pressure over eastern parts, heavy to very heavy rains, possibly lasting for one week, are expected over Odisha, Chhattisgarh, Jharkhand, Bihar, and West Bengal between the 11th and 19th June. The wet spell may extend further for few more days. These rains will be accompanied with high-velocity winds in excess of 50kmh, thunderstorms, and lightning strikes. Prolonged and consistent rains will pose a threat of localized flooding and inundation of low-lying areas. The rise of the water level in the streams and rivers of the region is quite likely. These inclement weather conditions will have the peripheral reach covering East Uttar Pradesh, East Madhya Pradesh, and Vidarbha in Maharashtra. Heavy rains are likely over these parts during the second half of the period.
The presence of a low-pressure area over the Bay of Bengal will also strengthen the western arm of the monsoon in the Arabian Sea. Accordingly, heavy rains are expected all along the West Coast in general and Konkan (including Mumbai) in particular for the next 5 days between 11th and 15th June. The western end of the monsoon will also advance further to cover more parts of Gujarat and Madhya Pradesh.