Your being on probation means that you also must consent to the search of your vehicle.
Police that know you may pull you over if they recognize you, however, they may not make a traffic stop unless they observe a violation of the law. Without observing a violation, he does not have probable cause to make a traffic stop. Whren v. United States (1996) 517 U.S. 806. Even if such driving were deemed unusual, an officer may not make a traffic stop simply based upon unusual driving. Taylor v. DMV (1995) 36 Cal.App.4th 812 (the officer’s subject belief that a suspect’s driving is unusual is insufficient to support a traffic stop).
Once there is a stop, the officer can definitely seize whatever is in plain view. He can also search the area within your reach if he has an articulable suspicion that there is evidence of a crime within that area. When it comes to needing a warrant to search more, he does not need to get that. However, to search a broader area, such as the trunk or the back seat, he still must have an articulable suspicion that there is a need to search. It is still not carte blanche. However, after something is found, you ought to know that such a suspicion will be fabricated to sanitize the search.