The Hindu Business Line : Westerly systems may combine to pack a punch

Thiruvananthapuram, March 7 Large swathes of the geography along the southeast coast, and hills and plains of the northwest are bracing to receive isolated to scattered rainfall over the next week.

The most notable development is in the northwest, where two weak western disturbances are seen combining to become a single, large entity, vested with a good north-to-south sweep.

This will ensure that the system scrapes the surface of the Arabian Sea off Gujarat where it would be able to harvest needed moisture to rustle up an induced circulation. If the system were to retain the amplitude after entering the northwest, it would go on to become the springboard for kicking up some wet weather in the north and northwest.

SHOWERS WELCOME

The exact contours would become clear as the system hits the home stretch around Sunday/Monday. The prospect of thundershowers would be welcome for the standing wheat crop, which relishes moisture and cooler climes. The threat of hailstorms, which could strike the crop as under, is what nags farmers.

In any case, Punjab, Haryana, Delhi and parts of west Uttar Pradesh are smack in the firing line of the evolving thundery weather. International models see the prospect of this zone of unstable weather propagating to the east and extending into the Indo-Gangetic plains.

EASTERLY WAVE

Another interesting possibility is of a firm and established belt of thundershowers triggered by enhanced easterly wave activity in the Bay of Bengal penetrating the country’s south-eastern flank right up to Orissa and West Bengal. This would happen as the easterlies veer to the northeast from the peninsular tip, taking advantage of the shift in the bearing of the seasonal ridge in the upper levels.

The Ensemble Forecast System of the US Navy’s Fleet Numerical Meteorology and Oceanography Centre ventures to suggest that the wet weather from the South would progressively couple with the precipitation in the northwest heralded by western disturbances.

PULSATING CHAIN

This could likely bring about a pulsating chain of showery and blustery weather linking the peninsular tip with the north and northwest through a narrow corridor straddling central India. Western India and the Karnataka-Konkan coast are likely to be left out of this activity, according to the forecast.

An India Meteorological Department outlook on Friday said that an incoming western disturbance is likely to cause isolated to scattered precipitation activity over western Himalayan region from Saturday and over the adjoining plains of northwest India from the next day. Current meteorological analysis suggests that the present scenario of maximum temperature is likely to persist during next 2-3 days and fall slightly thereafter.

Isolated rain/thundershowers are likely over Jammu and Kashmir, Arunachal Pradesh, Assam, Meghalaya, the Andaman and Nicobar Islands, south Tamil Nadu, Kerala and Lakshadweep.