GUWAHATI, April 30 ? There was a surplus rainfall of plus seven per cent between March 1 and April 24 this year in the State. There was also an improvement in the overall rainfall situation in the entire NE region during this period. But, this rainfall, however, does not have a clear-cut co-relation with the monsoon rainfall, said Meteorology office (Met) sources here today. The rainfall witnessed by the region now is pre-monsoon rainfall and the latest spurt in rainfall activities is due to the western disturbances prevailing since the last week of March. Conditions were also made favourable for such rainfall activities by the inflow of moist air from the Bay of Bengal since the last week of March.
In the pre-monsoon season, the sources said, frequency and amount of rainfall gradually increases from March to May. Moreover, pre-monsoon rainfall is widely variable, contrary to monsoon rainfall, said the sources. Between March 1 and March 27 this year, there was a 45 per cent deficit rainfall in the Arunachal meteorological sub-division. The deficit was 29 per cent in the Assam-Meghalaya meteorological sub-division during the period and in the Nagaland-Manipur-Mizoram-Tripura (NMMT) meteorological sub-division, the deficit was 47 per cent during the period, the sources said. But under the influence of the western disturbances, the situation improved since the last week of March and the deficit in Arunachal came down to five per cent, Assam witnessed a surplus of seven per cent and NMMT?s deficit also came down to 22 per cent. But, the sources said, the phenomenon of excess rainfall over the normal during the period between the last week of March and April 24 could be witnessed only in some parts of the region.
Elaborating, the sources said, the district of Barpeta, Cachar, Darrang, Dhubri, East Khasi Hills, Goalpara, Golaghat, Jorhat, Kamrup, Karbi Anglong, Kokrajhar, Morigaon, Nalbari, Nagaon, Sivasagar and Sonitpur witnessed significantly excess rainfall i.e. almost double the normal rates of rainfall during the week ending on March 27. In Arunachal Pradesh, East Kameng, Changlang, Dibang Valley, Tirap and Upper Subansiri districts and in Tripura, North Tripura, South Tripura and West Tripura also witnessed significantly excess rainfall during the week. For the week ending on April 3, East Kameng, West Kameng, Barpeta, Darrang, Dhubri, East Garo Hills, East Khasi Hills, Jaintia Hills, Kamrup, Kokrajhar, Morigaon, NC Hills, Nagaon, Nalbari, Sonitpur, North Tripura and West Tripura district witnessed significantly excess rainfall. For the week ending on April 10, East Kameng, East Siang, West Kameng, Barpeta, Dhubri, East Garo Hills and East Khasi Hills witnessed significantly excess rainfall. For the week ending on April 17, East Kameng, West Kameng and East Garo Hills witnessed significantly excess rainfall. For the week ending on April 24, Dibang Valley, East Kameng, East Siang, Lohit, Tirap, Barpeta, Darrang, Dhubri, Dibrugarh, East Garo Hills, Golaghat, Kamrup, Kokrajhar, Lakhimpur and Sonitpur witnessed significantly excess rainfall, the sources said.
It is pertinent to mention here that between March 1 and March 27 Arunachal experienced a rainfall of 54 mm, against the normal of 99 mm, Assam-Meghalaya, 53 mm, against the normal of 74 mm and NMMT 27 mm, against the normal of 51 mm, during the period. But, the cumulative rainfall in Arunachal, between March 1 and April 24 went up to 310 mm, against the normal of 326 mm. The cumulative rainfall figures in Assam-Meghalaya, during this period, went up to 275 mm, against the normal of 256 mm. In the case of NMMT, it became 149 mm, against the normal of 190 mm, during the period, the sources said.