2 C's in Junior Year. What are my chances of getting into low to mid tier UC's?

@DoctorP

Although the indidual colleges at UCSD don’t admit students by majors but there are capped majors that are harder to get into.

https://students.ucsd.edu/academics/advising/majors-minors/capped-majors.html

http://jacobsschool.ucsd.edu/assets/includes/academic/docs/Capped_Majors_FAQ.pdf