im on low risk probation regular sentense 1 year probbation 90 days in jail and just got my 3rd offense of possession of marijuana what will happen

Anytime that you are arrested on a new offense, you are subject to sentencing on the new offense.  In addition, if you are already on probation, you are subject to having your probation revoked and serving the suspended sentence on your previous sentence. Possession of Marijuana 3rd offense is an aggravated misdemeanor and your are subject to the penalties on this charge.  I've included a sentencing grid on my website http://www.robertpetersonlaw.com/Criminal%20Law%20Issues/Sentencing%20Grid%20for%20Crimes.aspx .  The sentence for marijuana 3rd offense  is 48 hours minimum sentence to 2 years prison, $625- $6250 fine, 35% surcharge on fine, $10 DARE surcharge, $125 Law Enforcement Surcharge, 180 day license revocation, and loss of federal benefits.  The conviction can also have immigration consequences.  This would be in addition to having your probation revoked in the previous case.