I can't tell you how hard it is to resist the temptation to ask you if you're crazy, Dude. So I won't.
Go to www.erowid.org
Your answers are there.
Why if you are on probation and you know there is a hammer hanging over your head would you take a chance by taking illegal drugs and drinking alcohol (I am assuming you were ordered not to drink alcohol). Well alcohol leaves the system fairly quickly and would not show. THC on the other hand takes a while. There will be evidence of at least the metabolite in your system. Get an attorney.
Mr. Driessen is a former Deputy DA in Orange County with over 8 years of criminal law experience. Nothing stated on this site shall in anyway be construed as legal advice, or as creating any attorney client relationship. If you would like to hire Mr. Driessen, feel free to contact him at www.theocduiguy.com.
Whether you show up "dirty" or not will depend on how much THC actually went into your system. The labs usually have cutoffs for minimum amounts. Get an attorney and good luck!
Are you high? Seriously? How do you prevent getting locked up? Don't be stupid and stop doing that which you already know you shouldn't be doing. And yes, you will probably test positve for THC. Hope it was worth it.