Monsoon Trough To Bring Heavy Rains Across Thailand
A weakening southwest monsoon will trigger thunderstorms across Thailand over the next 24 hours, with wave heights reaching 1–2 meters in the Andaman Sea and Gulf of Thailand, prompting mariners to exercise caution.
The Meteorological Department on July 20 forecast thunderstorms across Thailand over the next 24 hours, driven by a weakening southwest monsoon over the Andaman Sea, Thailand, and the Gulf of Thailand. Wave heights in the upper Andaman and upper Gulf are expected to reach 1–2 meters, with heights exceeding 2 meters in thunderstorm zones. Mariners are advised to navigate cautiously and avoid stormy areas.
Regional forecasts (6 p.m. today to 6 p.m. tomorrow):
**Northern Region:** 40% chance of thunderstorms, mainly in Mae Hong Son, Chiang Mai, Chiang Rai, Phayao, Nan, and Tak provinces. Lows 22–27°C, highs 28–36°C. Southwest winds 10–20 km/h.
**Northeastern Region:** 30% thunderstorm coverage, chiefly in Loei, Nong Khai, Bueng Kan, Sakon Nakhon, Nakhon Phanom, and Ubon Ratchathani. Lows 23–25°C, highs 35–37°C. Southwest winds 10–20 km/h.
**Central Region:** 30% thunderstorms, mostly in Uthai Thani, Kanchanaburi, Ratchaburi, Nakhon Pathom, Lopburi, and Saraburi. Lows 23–26°C, highs 35–37°C. Southwest winds 10–20 km/h.
**Eastern Region:** 30% thunderstorms, mainly in Nakhon Nayok, Rayong, Chanthaburi, and Trat. Lows 25–28°C, highs 33–37°C. Southwest winds 15–35 km/h. Sea waves 1–2 meters, exceeding 2 meters in storms.
**Southern Region (East Coast):** 30% thunderstorms, chiefly in Nakhon Si Thammarat, Phatthalung, Songkhla, Pattani, Yala, and Narathiwat. Lows 23–26°C, highs 34–36°C. Southwest winds 15–30 km/h. Sea waves around 1 meter, exceeding 2 meters in storms.
**Southern Region (West Coast):** 30% thunderstorms, mainly in Phuket, Krabi, Trang, and Satun. Lows 23–25°C, highs 33–35°C. From Phang Nga northward: southwest winds 15–35 km/h. Sea waves 1–2 meters, exceeding 2 meters in storms. From Phuket southward: southwest winds 15–30 km/h. Sea waves around 1 meter, exceeding 2 meters in storms.
**Bangkok and Metropolitan Area:** 30% thunderstorm chance, mostly afternoon to evening. Lows 26–28°C, highs 35–37°C. Southwest winds 10–20 km/h.
From July 21–25, rainfall will increase nationwide as the monsoon trough intensifies over the northern and upper northeastern regions.
