An intense high pressure system from China will cover the upper part of the country with thunder and showers during Feb 1-4, and temperatures in the North and Northeast will drop by two to four degrees Celsius, the Meteorological Department said on Sunday.
During that period, a northeast monsoon will intensify with more rain in the South, while wind-driven waves in the lower Gulf of Thailand are likely to be about 2 metres high. All vessels should proceed with caution.
In the overall picture, the weaker high pressure system over upper Thailand has largely led to rising temperatures with fog in the morning with thick patches in some areas, but cool spells remaining over the North and Northeast.