Mussoorie, June 20 -- The monsoon is expected to enter Uttarakhand in the next two days, bringing heavy rainfall in the districts of the Kumaon division first, and then the Garhwal region, the India Meteorological Department (IMD) Dehradun centre officials said on Thursday. Bikram Singh, director IMD Dehradun centre, said, "Monsoon is likely to arrive on June 21 or 22 and Uttarakhand is set to experience a spell of heavy rainfall from June 23, with the warnings for thunderstorms, lightning, and gusty winds across various districts. Residents and tourists are advised to exercise caution and stay updated on local advisories." According to the IMD Dehradun centre forecast on June 20, isolated heavy rainfall is likely in the districts of Tehri and Dehradun. All districts of Uttarakhand are expected to witness thunderstorms accompanied by lightning, intense spells of rain, and gusty winds reaching speeds of 40-50 kmph. The weather pattern will largely continue with isolated heavy rain forecast again in Tehri and Dehradun districts on June 21. The intensity of rainfall is expected to increase in some regions on June 22 with heavy to very heavy rain likely at isolated places in Bageshwar and Nainital districts. Additionally, heavy rain is also forecast for isolated areas in Nainital, Almora, Champawat, and Pithoragarh districts and all districts of Uttarakhand should prepare for thunderstorms accompanied by lightning, intense to very intense spells of rain, and gusty winds (40-50 kmph) at isolated locations. The challenging weather conditions are predicted to persist on June 23rd with heavy rain likely at isolated places in Almora, Nainital, Pauri, Tehri, Pithoragarh, and Champawat districts....