Another monsoon low to impact India

The monsoon low that formed in the Bay of Bengal this past weekend tracked westward across India earlier this week spreading a swath of heavy rain along its path. Heavy rain reached Mumbai and northwestern Maharashtra into Gujarat on Tuesday with rain continuing into Thursday.

Rain totals at Mumbai from 31 August to 2 September totaled 32.07 mm (12.63 inches) with rainfall totaling 46.89 mm (18.46 inches) at Dahanu. The low that brought the heavy rain will weaken over the next couple of days with drier weather expected to briefly return later this weekend.

Meanwhile, to the east, we are expecting another monsoon low to form over the northwestern Bay of Bengal just off the southern Odisha coast or northern Andhra Pradesh coast around 5 September. This low will track west-northwestward early next week spreading a swath of rain, some heavy, across central India.

This low can bring another round of heavy rain to northern Maharashtra into southern Gujarat from Tuesday through at least Friday. This rain could result in areas of flooding given the already saturated ground. Some rain from this low will reach westward to southern Pakistan during the middle and later part of next week.

Looking forward, the Madden-Julian Oscillation (MJO) is expected to push into phase 3 and 4 heading into the second full week of September. This should result in better rains in portions of northwestern India into parts of Pakistan late in the monsoon season.

Conditions should remain favorable for another late-season monsoon low to develop over the northwestern Bay of Bengal around 11 September. The exact track is a little uncertain, but the overall pattern should favor a west-northwest track once again. Whether this low will track toward Mumbai and Gujarat or track a little farther north remains to be seen, but heavy rain and the risk of flooding are expected along its eventual path.

The MJO pulse should help hinder an early withdrawal of the southwest monsoon from northwestern India and Pakistan and may even result in a late withdrawal. These late-season rains may chip away at the rainfall deficits across portions of central and northwestern India into Pakistan but probably will not totally erase these deficits.