By Sanjeev Kumar Patro
Bhubaneswar: October month has been the month of cyclones in Bay of Bengal. The hotter Bay of Bengal proves a fertile ground for cyclone genesis, provided the Madden Julian Oscillation (a rain bearing phenomenon over the seas) and easterly propagating Kelvin waves are present.
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As per NCICS model forecast, in the week from October 25 – November 3, the MJO will remain active over south Bay of Bengal, Northeast, Central Bay of Bengal and over the Andaman seas. Moreover, it also indicates presence of Kelvin wave extending from neighbouring south china seas to south east Andaman seas.
Given the conditions, model forecast by NCMRWF (National Centre for Medium Range Weather Forecast) shows strong easterlies blowing over to the Andaman seas from October 23. The model predicts formation of a cyclonic circulation over South east Andaman seas and extending up to the Gulf of Thailand.
Under its influence, on October 26, as per NCUM – Global model, a low pressure area is very likely to be formed over the south Andaman seas.
Model forecast by ECMWF and NCEP GFS agree with India’s NCUM-G model on the formation of low pressure area over the south Andaman seas, but differ on dates. NCEP-GFS model see the LPA forming as early as October 21. ECMWF also see formation of low pressure area on and around October 21 over the Andaman seas.
WILL LPA INTENSIFY TO CYCLONE?
As on today, all models are predicting cyclone genesis in October last week. The conditions are also favourable for cyclone genesis. Except NCEP-GFS, none of the models are predicting the intensification will be of cyclonic level. The reason it is too early to predict.
However, NCICS 10-day OLR forecast predicts cyclone genesis over the Andaman seas between October 25 and October 30.
Moreover, even as the conditions are favourable for the low pressure area intensifying into a cyclone, the vertical wind shear at present doesn’t seem to be in favour. But the haze around the scenario will clear up in next 48 to 96 hours.
ODISHA IMPACT
Be it cyclone or not, coastal Odisha may brace for some good pre Diwali rainfall. There are all indications that West Bengal and Bangladesh are all set to record heavy rainfall between October 21 and November 1.
