Kathmandu, June 9: Nepal is likely to witness the onset of the monsoon a few days later this year, as the key atmospheric conditions required for its arrival have not yet fully developed.
Last year, the monsoon entered the country on May 29, which was 15 days earlier than the normal onset date of June 13 and arrived through eastern parts of the country, covering most parts of Koshi Province.
Min Kumar Aryal, a senior meteorologist at the Meteorological Forecasting Division under the Department of Hydrology and Meteorology (DHM), said the conditions required for the onset of the monsoon have not yet been met, as the necessary atmospheric parameters are not currently present over Nepal.
He said the monsoon system is currently positioned over the southern part of the Bay of Bengal and has not advanced far enough towards the north to influence Nepal directly. He added that the monsoon has already reached Kerala in southern India.
However, a cyclone earlier drew moisture away towards eastern regions, affecting the northward advancement of the monsoon system.
Some moisture-laden winds are expected to enter the country between June 10 and 12, bringing cloudy skies and light rainfall to eastern, central and other parts of the country. “We are monitoring the situation and waiting for further updates on atmospheric parameters,” he added.
According to Aryal, moisture is likely to be present in the lower layers of the atmosphere, up to about two kilometres in altitude. However, for a full monsoon system to develop, strong moisture-bearing southerly winds need to extend to around five or six kilometres above the surface, which is not currently the case.
He said meteorologists are closely monitoring the situation. While rainfall may occur due to increased moisture and other weather systems, such precipitation alone does not signify the arrival of the monsoon.
The monsoon is characterised by a reversal of wind patterns, with moisture-rich winds flowing from the Bay of Bengal towards Nepal.
Aryal informed that the normal date for the monsoon’s arrival in Nepal is June 13. However, there is a possibility that this year’s onset could be delayed by a few days.
Meteorologists will review all necessary parameters, including moisture levels, rainfall distribution, wind patterns and pressure systems, over the coming days before making an official declaration.
“If the current trend continues, this year’s onset could be significantly later than last year’s monsoon,” he added. Further analysis of atmospheric conditions over the next two to three days will provide a clearer picture, he said.
