Agartala/Guwahati, Sept 3 (IANS): Even as northern and southern India receive copious rains, the Northeastern region comprising eight hilly States is witnessing a rainfall deficiency of 27 per cent in the first three of the four-month-long monsoon season, the Met said on Monday.
According to India Meteorological Department (IMD) officials in Guwahati and Agartala, the seasonal monsoon (June to September) rainfall is likely to be 93 per cent of the long period average over northeast India comprising Arunachal Pradesh, Assam, Meghalaya, Manipur, Mizoram, Nagaland, Sikkim and Tripura.
The eight northeastern States are divided into four meteorological sub-divisions.
An official report of the IMD, available with IANS, said that during the first three months (June to August) of the monsoon season the Nagaland, Manipur, Mizoram and Tripura sub-division recorded 1,013.1 mm (actual) of rainfall against the average rainfall of 1,227.9 mm.
Though there is a 17 per cent deficit in monsoon rainfall, according to the IMD standard this is considered as normal.
Arunachal Pradesh sub-division witnessed the highest deficit of 35 per cent rainfall, recording 921.6 mm rainfall (actual) against the normal average of 1,412.9 mm.
With 29 per cent deficit, Assam and Meghalaya sub-division recorded 1,048.2 mm rainfall (actual) against the normal average of 1,486.8 mm.
Sikkim and adjoining Sub-Himalayan areas of West Bengal registered 19 per cent less rainfall recording actual rainfall of 1,316.9 mm against normal average of 1,623.8 mm.
Private weather forecaster Skymet said that a cyclonic circulation exists over Assam, thus, rains would increase over Northeast India resulting in moderate to heavy rains.
IMD Director Dilip Saha told IANS: "Rain producing systems, including deep depressions, were not very much evenly active in the entire northeastern region.
"However, the huge deficiencies in rainfall were likely to be covered in the later part of the monsoon in Assam and Arunachal Pradesh."
"The frequency of movement of monsoon factors were also slightly favourable in Nagaland, Manipur, Mizoram and Tripura sub-division," he said adding that in the Northeast, though the normal monsoon period is June to September, it some times continues until the first or second week of October.
According to IMD stipulation, Saha said if the monsoon rainfall recorded plus-minus 19 per cent it would be termed as normal, if it recorded plus 20 per cent it would be described as excess and minus 20 per cent to minus 59 per cent would be notified as deficient.
According to Skymet, normally monsoon covers the entire stretch of Northeast India during the first week of June. But, in 2018, despite making an on-time arrival, the pace of the southwest monsoon is slow.
"Northeast India is one of the rainiest pockets of the country. During the Southwest Monsoon season and almost 30 per cent of the seasonal rainfall is contributed by this region," it said.
According to an IMD report, during the four-month-long monsoon period, Meghalaya's Cherrapunjee holds the record of being the second wettest place on earth, even as Mawsynram, also in Meghalaya, now holds the Guinness record for the highest amount of rainfall -- 11,873 mm -- in a year.
Cherrapunjee still holds the record for the highest amount of rainfall in a calendar month, with 9,300 mm of rain recorded in July 1861.