KATHMANDU, APRIL 21 The Department of Hydrology and Meteorology has issued a special heatwave bulletin warning of extreme heat conditions across Nepal's Terai belt over the next three days, with temperatures of 40 degrees Celsius or above already recorded in parts of Lumbini and Sudurpashchim Provinces since Monday. Temperatures around 38 degrees Celsius have also been recorded in parts of Madhesh, Bagmati, Gandaki and Lumbini Provinces. The department warned that heatwave conditions are likely to persist in the western Terai of Lumbini and Sudurpashchim Provinces for the next three days, while hot day conditions are expected across the Terai, valleys and gorges of Madhesh, Bagmati, Gandaki and Sudurpashchim Provinces. Among the cities forecast to experience the most intense heat on Tuesday are Bhairahawa, where the maximum temperature is expected to reach between 40 and 42 degrees, Nepalgunj and Dhangadi between 39 and 41 degrees, Dipayal between 38 and 40 degrees, and Janakpur and Birendranagar between 37 and 39 degrees. Kathmandu is forecast to see mainly fair weather with daytime temperatures between 29 and 31 degrees and nighttime lows between 15 and 17 degrees. The department said the country is currently under the partial influence of westerly and local winds. In the Himalayan region, generally cloudy conditions are expected through the day with a chance of moderate rain or snowfall accompanied by thunder and lightning in a few places. The Hilly region and Terai are expected to remain partly cloudy to mainly fair. Overnight, light rain or snowfall is possible at one or two places in the Himalayan regions of Koshi, Gandaki and Karnali Provinces. The department warned that prolonged exposure to extreme heat can cause exhaustion, excessive thirst, headache, dizziness, muscle cramps, fainting and vomiting. It advised the public to remain indoors or in cool places during peak heat hours, avoid prolonged sun exposure, wear light-coloured cotton clothing, cover the head when going outside, and drink water and fluids regularly. Those experiencing health problems are advised to seek guidance from health workers promptly. The Meteorological Forecasting Division said it will issue updated bulletins daily and urged the public to follow the latest advisories.