Date:06/01/2008 URL: http://www.thehindubusinessline.com/2008/01/06/stories/2008010651080300.htm

Back Wet spell in North may last for a week

Moisture feed from Arabian Sea to peak within next two days

Tamil Nadu and Puducherry will come under more rainfall by the end of the week (January 14).

Vinson Kurian

Thiruvananthapuram, Jan. 5

The emerging wet session in north and northwest India, the first meaningful round of winter showers, is expected to last for at least a week, according to consensus forecasts by international weather models.

Weathermen set great store by the train of western disturbances being unleashed into the country by the upstream winter storm, which would combine well with the strong moisture feed from the Arabian Sea to result in good precipitation.

In fact, the moisture feed from the Arabian Sea is seen establishing from Monday, and peaking within the next two days to coincide with the arrival of another western disturbance.

This moisture will help pump up the precipitation and snowfall, respectively, in the plains and the hills.

DIRECT IMPACT

The moisture feed will be extended in perpetuation by an easterly wave, currently active over Tamil Nadu and Kerala, dipping into the Arabian Sea and getting directed to the north by southwesterly flows.

Moisture transport thus, re-curving is shown to concentrate around the Gujarat coast before getting pulled into the circulation (likely an ‘induced low’) associated with the western disturbance/trough.

Both the US National Centres for Environmental Prediction (NCEP) and the Ensemble Forecast System (EFS) of the Fleet Numerical Meteorology and Oceanography Centre (FNMOC) of the US Navy support this outlook. The European Centre for Medium-Range Weather Forecasts (ECMWF) has retained its outlook for some violent weather in India’s east and northeast later during the week as the western disturbance tracks an east-southeasterly direction.

MORE FOR SOUTH

Meanwhile, Tamil Nadu and Puducherry, one of the two meteorological sub-divisions to post excess rainfall during the winter season till date, will come under more rainfall by the end of the week (January 14) as a strengthening La Nina over the Pacific trains oodles of moisture into the south China Sea and the Bay of Bengal.

Helpful northeasterlies will force a bulk of the feed across Indonesian and Sri Lankan latitudes, in the process spilling some into the Tamil Nadu coast and over adjoining Kerala. Long-range forecasts made available by the International Research Institute (IRI) of Columbia University and a few other models indicate these rains would be only the harbinger of more organised and sustained rainfall in the south peninsula as the strong La Nina gets entrenched.