A 39-year-old Port Huron man was arrested after allegedly starting a fire at the Blue Water YMCA yesterday morning.  It is reported that surveillance videos showed the suspect dumping trash inside the west entrance of the YMCA and setting it on fire.  Local firefighters and officers responded to the fire alarm shortly after 1:40 a.m. Sunday to find flames in the entrance.  A be on the lookout notice was put out and the suspect was picked up near Port Huron Hospital within an hour of the report.  It is also reported that the suspect is the same man who was warned to leave the YMCA sometime on Saturday.  Arraignment is expected to take place today on charges of preparation to burn and arson of real property. Both charges are felonies.