Landslide warnings have been issued to eight districts.
The National Building Research Organisation said landslide warnings issued to the Colombo, Kalutara, Kandy, Matale, Nuwara Eliya, Kurunegala, Kegalle, and Ratnapura districts will be in place till 8.30pm.
Meanwhile, the NBRO requests persons residing in landslide prone areas to remain vigilant.
The Department of Irrigation has warned of possible floods in several areas surrounding the Attanagalu Oya and the Kalu, Kelani, Ging and Nilwala Rivers.
The Department said the warning was issued owing to heavy showers expected in certain parts of the island during the next 24-hour period.
Accordingly, residents in low lying areas of the rivers have been requested to remain vigilant due to showers expected during the days ahead.
Meanwhile, the Department of Meteorology predicts showers at times in the Western, Sabaragamuwa and North-Western provinces and in Kandy, Nuwara-Eliya, Galle and Matara districts.
Heavy showers above 100mm may occur at some places in the Western and Sabaragamuwa provinces.
Several spells of showers may occur in the Northern and North-central provinces.
Showers or thundershowers will occur at several places elsewhere in the evening or night.