As of right now - BKK in the central city areas (tourist interest with the exception of the Chatuchak Weekend Market which does have some flooding, financial/business area, nightlife area) have no flooding but there doesn't seem to be any reliable source of information (including the government) of flooding potential. However, it is indicated that all efforts will be undertaken to prevent central Bangkok from flooding. People in the flooded areas have become agitated and opening (destroying) some flood gates which could cause flooding in central Bangkok.

FWIW, they've been saying for a month that the flood is coming (I'm originally Thai and we were there in mid-Oct).