India Meteorological Department (IMD) has forecast heavy rainfall with thunderstorms and lightning in Tamil Nadu, Puducherry, Karaikal and Kerala today. The IMD also said that dense to very dense fog conditions are very likely to prevail in the night and early morning hours over Punjab, Haryana-Chandigarh, Delhi, and West Rajasthan today. Further, the weather department has forecast a gradual fall in minimum temperatures by 2-3 degrees Celsius over Northwest, West and Central India during the next 4-5 days.