The US Embassy and the British Embassy in Bangkok have just released a travel advisory for Thursday 27th September 2012.
The Royal Thai Police has informed the U.S. Embassy in Bangkok, Thailand, that a demonstration involving several hundred people is planned on Wireless Road in front of the Embassy beginning at 10 AM on Thursday, September 27. Although the demonstration is not expected to be violent, it may cause traffic disruptions in the area. The Embassy will remain open for consular service appointments.
The British Embassy were actually the first to release the advisory and their one has a little more information:
A demonstration is expected to take place from 10:00 on Thursday 27 September outside the United States Embassy on Wireless Road. Demonstrators are expected to assemble at Lumpini Park and then move to the US Embassy. There is likely to be disruption and traffic congestion. You are advised to avoid all demonstrations and protests.
No-one is saying who will be protesting. As the protesters are expected to assemble at Lumpini Park first, we can guess that it may be another Muslim group protesting against the anti-Islam video posted on Youtube. If so, it would seem that they have learned their lesson about staging protests in the afternoon. During the rainy season, it is more likely to rain early morning and late afternoon.
Unlike last time, the US Embassy plan to remain open during the protest. However, you are advised that unless you have essential business at the US Embassy you should re-schedule your appointment for another day. Traffic on Wireless Road in front of the embassy will most likely be disrupted. The British Embassy is not affected by this event.