The Northern Limit of Monsoon line (NLM) is currently lies in the foothills of Himachal Pradesh. Its eastern extension in northeastern states is likely to turn downward into northwest Bay of Bengal where it might build up into a circulation to increase rainfall afterward.
However, rain with moderate intensity is likely to continue over east Bihar, Sub-Himalayan West Bengal and Sikkim as moisture-laden southeasterly winds are colliding into the hills and helping precipitation. Heavy rain is also likely at a few places in these states in the next twenty four hours.
Off shore trough Strengthen along the west coast
Along the west coast, the off shore trough extended from Konkan to Kerala is rejuvenating and thus attracting more showers in coastal areas of Kerala, Karnataka, Goa and Maharashtra.
Mumbai is likely to see an increase in rainfall activity after twenty four to forty eight hours.
Troughs are places where winds from opposing directions meet (or winds turn) and atmospheric pressure is low while the turbulence caused by such interaction (or turning) leads to rain, thundershowers and storms. Southwesterly winds are turning into northwesterly along this trough.
In central Peninsula, Orissa, Chhattisgarh along with Vidarbha and adjoining region are expected to get moderate rainfall in the next twenty four hours.
In southern Peninsula, seasonal light showers are expected over interior Karnataka and Andhra Pradesh. Isolated moderate showers are expected in east coastal areas of Andhra Pradesh and Orissa. A few places in Tamil Nadu including capital Chennai will receive light seasonal drizzles in the next twenty four hours.