Variable scope

I little confused about variable defenition in the following code:

#include <msp430.h>

int b = 3;

int main(void) {
  WDTCTL = WDTPW | WDTHOLD; // Stop watchdog timer

  b=2;

  for(;;){;}

  return 0;
}

When I debug the program and watch the variable 'b', why does it not initialize to value of 3?  It does change to value of 2 as I step through the program, but why would it not initialize to value of 3?

My uC is MSP430FR5739, IDE is CCS 5.3