A low pressure area covering the South China Sea and the southwest monsoon over the upper Andaman Sea and upper Thailand are both weakening, but isolated heavy rain is likely in the North and Northeast between 6am today and 6am on Monday, the Meteorological Department announced on Sunday.
People living in lowlands and on foothills in the two regions are warned against possible flash floods.
Thundershowers and heavy rain are forecast over 70% of the North. Provinces to be affected are Chiang Mai, Chiang Rai, Lamphun, Lampang, Phayao, Nan, Phrae, Tak, Uttaradit, Phitsanulok, Kamphaeng Phet and Sukhothai.
In the Northeast, downpours are expected in Loei, Nong Bua Lamphu, Nong Khai, Bung Kan, Udon Thani, Sakon Nakhon, Nakhon Phanom, Chaiyaphum and Khon Kaen.