New Delhi, July 18 : Northern India is likely to witness intense rainfall activity between Sunday to Wednesday (July 21), and the west coast till July 23, the India Meteorological Department (IMD) forecast on Sunday. It has also predicted moderate to severe thunderstorms with lightning at isolated places over Uttar Pradesh, Gujarat, Madhya Pradesh, and east Rajasthan during the next 24 hours, and warned of casualties to people and animals staying outdoors. "Rainfall activity is very likely to increase with widespread rainfall to isolated heavy to very heavy rains very likely over the western Himalayan region (Jammu, Kashmir, Ladakh, Gilgit, Baltistan and Muzaffarabad, Himachal Pradesh and Uttarakhand) and adjoining northwest India -- Punjab, Haryana, Rajasthan, UP and north Madhya Pradesh -- from July 18 to 21," the IMD said in a statement. However, there will be a decrease in rainfall activity over the same regions thereafter, it said. According to the Met department, isolated extreme heavy rainfall is also very likely over Uttarakhand between July 18 and July 19. Delhi is likely to witness moderate to heavy rainfall, it said. Isolated heavy rainfall is likely over east and adjoining central India from July 22 onwards. /IANS