People must beware of stormy weather and gusty wind and stay away from big trees and unsecured billboards, the agency said.
At 5am the temperature was forecast for Loei and Kanchanaburi at 41°C while Mae Hong Son, Nan, Phetchabun, Khon Kaen, Nakhon Ratchasima, Ubon Ratchathani and Nakhon Sawan were set for 40°C.