Tuesday, July 21, 2009

Break-monsoon phase may not last

Emerging meteorological features over North India may be compatible with conditions identified as leading up to an imminent 'break-monsoon'.

But this would at best be a temporary phase, according to international model projections. A 'break-monsoon' is an intra-seasonal recess in rainfall over the farming heartland in central India and the northwest.

In a classic 'break-monsoon' phase, the seasonal trough retreats to the Himalayan foothills, rains shut out over central India and the northwest, and get confined to the west coast, east India and the North-East.

TO REORGANISE

Monsoon westerlies from the Arabian Sea may show a weakening trend in the short-term, but are forecast to reorganise themselves and get back to business over the next seven to 10 days.

The trigger for 'break monsoon' call was the alignment of the seasonal trough to north of its normal on Monday and a tendency for ongoing rains from a depression in the Bay of Bengal to get concentrated to north India.

'LOW' UNLIKELY

There is no 'low' being forecast to take shape to anchor the flows in the Bay for the next seven days at least, with the European Centre for Medium-Term Forecasts not maintaining its outlook for one anymore.

Break or not, monsoon easterlies are expected to dump their contents over parts of rain-denied northwest India as also Bihar and the rest of east and North-East India, said Dr Akhilesh Gupta, lead operational forecaster and Adviser to the Ministry of Science and Technology. The Global Forecasting System model of the US Navy's Fleet Numerical Meteorology and Oceanography Centre as well as the Climate Prediction Centre of the National Weather Services showed fairly widespread rains settling over parts of northwest India, Bihar and the North-East during the rest of this week.

Southwesterlies from the Arabian Sea would ensure central India, west-central India and the west coast their quota.

Meanwhile, Sunday's well-marked 'low' intensified to become a depression on Monday. The system was expected to move west-northwest and cross the Orissa-West Bengal border by the evening.

The monsoon trough passed through Ferozpur, Meerut, Bareilly, Kanpur, Daltonganj, the centre of the depression and southeastward into east-central Bay of Bengal, an India Meteorological Department (IMD) update said.

WIDESPREAD RAINS

Widespread rainfall with heavy to very heavy falls and isolated extremely heavy falls has been forecast for Orissa during the next 24 hours.

Fairly widespread rainfall activity with heavy to very heavy falls is likely over Gangetic West Bengal, Jharkhand, Chhattisgarh, east Madhya Pradesh, north Andhra Pradesh and Vidarbha during the next two days.

Fairly widespread rainfall activity with isolated heavy falls is likely over Himachal Pradesh, Uttarkhand and Uttar Pradesh during the same period.

Squally winds speed reaching 45-55 km/hr gusting to 65 km/hr are likely along and off the Orissa and West Bengal coasts during the next 24 hours.

ROUGH SEAS

The sea condition will be rough to very rough along and off these coasts. Fishermen are advised not to venture into the sea.

According to the Chennai Met Centre, the monsoon has been active over south interior Karnataka and coastal Andhra Pradesh.

Forecast for the next two days said that rain or thundershowers are likely to occur at many places over Kerala, coastal and south interior Karnataka, north coastal Andhra Pradesh and Telangana.

Thundershowers are also forecast at a few places over Lakshadweep, north interior Karnataka and south coastal Andhra Pradesh.

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