Mumbai: An off-shore trough is moving from the Maharashtra coast to the Karnataka coast at the main sea level. Extreme heavy rainfall is likely in the next 24 hours. 

Dr Jayanta Sarkar, Head of IMD Mumbai, said, "We have issued red alert in Mumbai Metropolitan Region (MMR) for day one and orange alert for July 20-23."  

Significant Weather Features by IMD: 

♦ The western end of the monsoon trough at mean sea level continues to run close to its normal position and is likely to shift gradually northwards from 20th July. Its eastern end lies north of its normal position and is likely to continue there during the next 2 days and shift southwards. 

♦Subsequently, a Low-Pressure Area is likely to form over Northwest Bay of Bengal around 23rd July. 

♦An off-shore trough at mean sea level runs from Maharashtra coast to Karnataka coast. It is likely to persist during the next 3-4 days. 

♦A shear zone runs along Lat. 17°N in middle tropospheric levels and is likely to persist till 20th July. 

Under the influence of the above system: 

♦Present spell of heavy to very heavy Rainfall activity is very likely to continue till 20th with isolated heavy to very heavy falls very expected over Western Himalayan Region (Jammu, Kashmir & Ladakh, Himachal Pradesh and Uttarakhand) and adjoining northwest India (Punjab, Haryana, East Rajasthan, West Uttar Pradesh and northwest Madhya Pradesh). Decrease in rainfall activity over the same regions thereafter. 

♦Isolated extremely heavy falls very likely over Jammu Division, Himachal Pradesh, Uttarakhand and Haryana on 19th July and heavy to very heavy rainfall on 20th July over the same areas. 

♦Moderate rainfall at most places with isolated intense spells is very likely over Delhi during the next 24 hours. 

♦Widespread rainfall with isolated heavy to very heavy rains is very likely to continue over the west coast and adjoining inland areas during the next 4-5 days. Isolated extremely heavy also falls very likely over Konkan & Goa & adjoining Ghat areas of Madhya Maharashtra on 19th and 21st & 22nd July. Isolated heavy to very heavy rainfall over south Gujarat region on 19th July 2021. 

♦Fairly widespread to widespread rainfall with isolated heavy falls likely over east and adjoining central India on 22nd & 23rd July.

 ♦Moderate to Severe thunderstorms with lightning are very likely at isolated places over Uttar Pradesh, north Madhya Pradesh and East Rajasthan during the next 24 hours.