They likely popped up in your social media feed on Monday and Tuesday.
Photos and videos of the ominous and stormy looking clouds in the sky over Prachuap Khiri Khan and Phetchaburi.
Some of the best photos of the clouds were taken next to the site of the new night market on Sam Roi Yot beach.
According to Thailand’s Meteorological Department (TMD), the breathtaking cloud formation was likely the result of an ‘arcus’ or ‘shelf’ cloud.
While not dangerous, an arcus cloud is a fairly rare phenomenon.
Arcus clouds are spectacular low level, long thin clouds that are associated with thunderstorms, stormy weather and heavy rain.
According to the TMD, they occur when a cold downdraft from another type of a cloud formation – a cumulonimbus cloud – hits the ground and spreads rapidly, causing the existing moist warm air to move upwards. As the moist air rises, the water vapor condenses into the patterns associated with the arcus cloud.
The TMD also said that the presence of an arcus cloud points to one thing – more unsettled and stormy weather.
According to the TMD, scattered thundershowers and isolated heavy rains are forecast in Hua Hin and over Prachuap Khiri Khan for much of the next week.