Meanwhile, private agency Skymet Weather announced that the southwest monsoon
has arrived in Kerala before its scheduled onset, however, India's official forecaster IMD
said conditions are not yet ripe for the declaration. Skymet Weather CEO Jatin Singh said all conditions such as rainfall, Outwave Longwave Radiation (OLR) value and wind speed have been met to declare the arrival of the southwest monsoon
Light to moderate rain lashed the national
capital on Friday, bringing the mercury several notches below normal.
The onset of monsoon over Kerala marks the commencement of a four-month rainy season in the country. The country receives 75 per cent of the rainfall
from June to September.
Skymet had predicted that monsoon will hit Kerala on May 28 with an error margin of plus or minus 2 days. Whereas, the India Meteorological Department (IMD) had said the monsoon will make an onset over Kerala on June 5, four days after its normal onset date.
Earlier this week, it said a cyclonic circulation in the Bay of Bengal will help in the advancement of the monsoon and it could reach Kerala on June 1, its normal onset date.
According to the IMD, there are three major conditions to declare the onset of monsoon. The first is if, after May 10, 60 per cent of the 14 weather stations -- Minicoy, Amini, Thiruvananthapuram, Punalur, Kollam, Allapuzha, Kottayam, Kochi, Thrissur, Kozhikode, Thalassery, Kannur, Kudulu and Mangalore -- report rainfall
of 2.5 millimeters or more for two consecutive days, the onset over Kerala will be declared on the second day. The second is the depth of westerlies should be maintained up to 600 hectopascals (hPa) and the third is the Outwave Longwave Radiation should be below 200 watts per square meter (wm-2).
On Friday, light to moderate rain lashed the national
capital on Friday, bringing the mercury several notches below normal. Strong winds swept across the city and a few areas reported hailstorm. The Safdarjung observatory, which provides representative figures for the city, recorded 3.5 mm rainfall
and a maximum of 37 degrees Celsius, three notches below normal, officials said.