Normal monsoon likely this year

The monsoon may be normal this year. This optimism is based on preliminary meteorological observations indicating the development of La Nina in the Pacific ocean.

(La Nina is the opposite of El Nino phenomenon that normally causes poor monsoon. La Nina is characterised by unusually cold ocean temperatures in the equatorial Pacific, while El Nino represents unusually warm temperatures in that ocean.)

According to National Centre for Medium Range Weather Forecasting (NCMRWF) Director Akhilesh Gupta, there is no instance in the past of a poor monsoon in a La Nina year.

"The monsoon has to be normal or above normal if La Nina develops this year", he told the Business Standard.

But meteorologists will have to wait for a couple of weeks more to be sure how strong the emerging La Nina will become. "Clearer signals about La Nina are likely to be available by around the first week of April," Gupta said.

He said the present wide-spread rains in a large part of the country are unlikely to influence the ensuing monsoon. However, hot and dry weather in April would be helpful in strengthening the monsoon current.

The squally winds and thunderstorms occurring in several regions, including the rain-starved north-western states, would have a mixed impact on crops.

While heavy winds, hails and thunderstorms may adversely affect the main rabi crop of wheat, light rains will generally be beneficial for it.

Crops like mung and vegetables, which were currently being sown in several regions of Bihar, Uttar Pradesh and other states, would get a boost from these rains, Gupta said. He was, however, sceptical about the impact of high temperature in the entire month of February over the standing crops, including wheat.

Sharing this concern, Indian Council of Agricultural Research (ICAR) Deputy Director-General JS Samra said the above normal temperature in the whole of the last month had adversely affected the crops, notably wheat. The effect was greater due to high temperature in the second fortnight of February.

The fall in temperature in March, coupled with the present wet spell, might help the wheat crop to recover somewhat, but the extent to which such a rejuvenation took place was yet to be seen, Samra said. Though there were some reports of an attack of aphid pest on wheat, this was controlled by farmers by spraying suitable pesticides.

The NCMRWF attributes the present rains and hailstorms to an active western disturbance which lies over north-west India.

Besides, another induced cyclonic circulation has developed over Gujarat and adjoining south Rajasthan. A deep north-south trough in middle and upper troposphere is also associated with these two systems.

"Such a scenario is conducive for rainfall activity accompanied with thunderstorms with squally winds and isolated hailstorms over a larger area.

As a result, scattered to fairly widespread rainfall activity is likely over plains of north-west and north India, central India, Gujarat, Maharashtra, South Rajasthan, and eastern parts of the country during the next two to three days", Gupta said.

Uttar Pradesh, western parts of Bihar and central India comprising Maharashtra, Madhya Pradesh and Chhattisgarh might receive isolated heavy rains.

Isolated hailstorm activity was also expected in central India, especially in Madhya Pradesh, Chhattisgrah and Maharashtra, during next two days.

Both day and night temperatures were likely to fall by 2-4 degrees celsius over the north-west, north and central India during this period.