Date:21/08/2008 URL: http://www.thehindubusinessline.com/2008/08/21/stories/2008082150341100.htm

Back Bay system forms, to trigger rains in East

Vinson Kurian

Thiruvananthapuram, Aug 20 India Meteorological Department (IMD) has said on Wednesday that an upper air cyclonic circulation has formed over the North Bay of Bengal and adjoining coastal areas off West Bengal and Orissa.

However, the Noida-based National Centre for Medium Term Weather Forecasting declared the system as a full-fledged ‘low’.

The IMD, on its part, expected the western end of the monsoon trough too to behave by moving south to its normal alignment, which could set up the stage for a stronger system (a likely ‘low’) in the Bay.

International models saw the system tracking a course along the southeast coast for sometime.

The eastern end of the trough passed through Lucknow, Gaya, Bankura, Kolkata and thence southeastwards into Northeast Bay where it hosted the circulation/‘low.’

Scattered to fairly widespread rainfall activity is likely over East India during the next two days.

The prevailing upper air cyclonic circulation over land over East Uttar Pradesh and neighbourhood drifted overnight to the west to lie over West Uttar Pradesh and adjoining northwest Madhya Pradesh and East Rajasthan.

This is expected to being scattered to fairly widespread rainfall activity over parts of northwest India and Rajasthan during next three days.

Fairly widespread rainfall activity is likely over Jharkhand, Uttar Pradesh, north Madhya Pradesh and north Chhattisgarh and later Rajasthan during the next three days.

BLOW-UP OVER TN

During a weak monsoon phase such as this, the southeast coast manages to wrest its share of scattered to isolated heavy seasonal showers thanks to peculiar atmospheric features.

During the 24 hours ending Wednesday morning, rains occurred at a few places over Tamil Nadu, Rayalaseema, Coastal and South Interior Karnataka while they were isolated over Coastal Andhra Pradesh, Telangana, Kerala, Lakshadweep and North Interior Karnataka.

Notable heavy rainfall events during this period were (in cm): Chennai, Thamaraipakkam and Poondi -10 each; Red Hills-9 (all in Tamil Nadu); and Palamaner-8 and Puttur-7 (Andhra Pradesh).

Forecasts for the next two days said rain or thundershowers are likely to occur at many places over Coastal Andhra Pradesh and Telangana and at a few places over Tamil Nadu, Puducherry, Kerala, Lakshadweep, Rayalaseema and Karnataka.