Total noob traveler Portland heading to bangkok for 3 months??

hello. Sorry for the quick typing but I'm feeling a bit rushed for asnwers. My name is Matthius and I am heading to Bangkok from Portland on dec the 2nd with a return trip set for feb 28th. My goal is to simply tour the kindom and explore the country. So I understand that when I arrive I can get a 30 visa. BUT my ticket is schedualed for 3 months or from dec 2nd till feb 28th. What should I tell the consulate when I arrive? Thank you for any knowlege you may have in this are. Let's keep it factual here to avoid confusion please. THX real big in advance. Matt

Tell them that you'll leave in 30 days... Fly out to Singapore or somewhere and fly back in :)

Thanks! I'm also told that my airline may not let me fly without a 60 day or more visa. Gonna try to grab it the day before my flight..we'll see. Thanks again! I'm brand new at this as you can see. :)