Though officially the onset of monsoon in the country is yet to be declared, the northern limit of monsoon has touched the extreme south/ southeast part of Bangladesh close to Mizoram. The normal date of onset of monsoon over Kerala Coast is June 1, while over the city of Guwahati, the onset normally takes place on June 5. By June 6, NE region is generally covered by monsoon. However, variation of seven days in this respect is quite possible, said H Pathak, Director of the Regional Meteorology Centre (RMC) here. He said that as per the forecast, further advance of monsoon is likely to be effective within the next two to three days over Kerala. The Pune Weather Office of the India Meteorology Department announces the advance of monsoon, Pathak said. The areas covered by the northern limit of monsoon yesterday included southern parts of the Arabian Sea, most parts of the South Bay of Bengal, some parts of the Central Bay of Bengal, some parts of the Bay of Bengal and the Arakan Coast, besides the extreme south/southeast part of the Bay of Bangladesh, he said. Over the NE region, pre-monsoon rainfall is still occurring. But the impact of this pre-monsoon rainfall in the western part of Assam is comparatively less. At 8-30 am today, Khonsa in Arunachal Pradesh reported 8 cm of rainfall, Chauldhowaghat near Tinsukia reported 9 cm of rainfall while each of Khowang, North Lakhimpur and Itanagar reported 5 cm of rainfall, he said. During these days, a trough of pre-monsoon low-pressure system is seen running from Rajasthan to Northeast Bay of Bengal across North Madhya Pradesh, North Chhattishgarh, Jharkhand, Gangetic West Bengal and North West Bay of Bengal. A secondary trough is also seen running from Jharkhand to NE Assam across north Gangetic West Bengal, Bangladesh and Meghalaya. Under the influence of this secondary trough, occurrence of rainfall over NE region is observed, said the RMC Director.