GUWAHATI: The southwest monsoon hit the eight northeastern states including Sikkim and most parts of sub-Himalayan West Bengal on Sunday.
Light to moderate rain occurred at most places over Arunachal Pradesh, Assam, Meghalaya, Manipur, Mizoram and Tripura and light rain occurred at a few places over Nagaland with very heavy rain at isolated places over Meghalaya and Tripura during the last 24 hours.
The IMD’s weather forecast says thunderstorms with lightning are very likely to occur at isolated places over Assam, Meghalaya, Nagaland, Manipur, Mizoram and Tripura for the next 24 hours.
The Met office also warned of heavy rain at isolated places over the six states during the period.
Heavy rain is very likely to occur at isolated places over Arunachal Pradesh, Assam and Meghalaya on Tuesday.
For the next two days, the Met office has predicted heavy rain at isolated places over Assam and Meghalaya.
Normally, monsoon covers most parts of the northeast by June 5.
However, in the past 10 years, barring 2017 and 2018, monsoon arrived in the region on June 6 and afterwards.
“The southwest monsoon has further advanced into more parts of central Arabian Sea, some parts of Maharashtra, entire Karnataka, some parts of Telangana, entire Tamil Nadu, some parts of Andhra Pradesh, more parts of central Bay of Bengal and northeast Bay of Bengal and the entire northeastern states of India and also most parts of the sub-Himalayan West Bengal and Sikkim on Sunday,” said Sunit Das, a senior scientist from the Regional Meteorological Centre of the IMD.
As per IMD’s long-range forecast, seasonal rainfall in the northeast is most likely to be below normal this monsoon (from June to September) with less than 95 per cent of the long period average (LPA).
In its long range forecast for the southwest monsoon, the IMD recently predicted that rainfall over the country as a whole is most likely to be normal, ranging from 96 per cent to 104 per cent of LPA.
The Met office said after onset of the southwest monsoon over Kerala, it advanced further and caused rainfall over parts and sectors of the meteorological sub-divisions, maintaining the spatial continuity of the northern limit of monsoon.
For the last four to five days, the three meteorological sub-divisions of NE region received light to moderate rainfall at many to most places with isolated heavy rainfall.
By Sunday, conditions became favourable for the onset of monsoon in the region.
Currently, a cyclonic circulation lies over sub-Himalayan West Bengal and neighbourhood and extends upto 1.5 km above mean sea level with a trough aloft between 2.1 km & 3.1 km above mean sea level roughly along Long.
90 degree East to the north of Lat.
23 degree North.
As a result of the weather system, weathermen said, the northeastern region is likely to get more rains.
Most of the northeastern states experienced deficit rainfall during the three month-long pre-monsoon season that culminated on May 31.
Except Meghalaya, which received normal rainfall since March 1, six other northeast states recorded only deficit rainfall during the period.
With a maximum shortfall of 67 per cent and 60 per cent, rainfall has been a “large deficit” in Mizoram and Tripura, respectively.