The Northern region is expected to suffer a scorching temperature between 39 degrees Celsius and 40 degrees Celsius in coming days after sudden cold days.
The highest temperature in the Central and Northwestern mountainous areas has averaged at 35- 37 degrees Celsius in two recent days because of an impact of a low- hot pressure zone in combination with the southwest monsoon causing foehn wind effect.
The weather center also warned that the heatwave would expand to whole northern provinces on May 16- 19, with an average temperature of 36- 39 degrees Celsius, even above 39 degrees Celsius in some places.
The hot spell is forecast to end after the next three or four days.
From May 20, the Northern and Central regions are predicted to see cooler days because of the low pressure trough being compressed by a continental air. SGGP