FIG. 1 is a top perspsective view of my new, original and ornamental design for a portable outdoor shelter;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a right side elevational view thereof;
FIG. 4 is a left side elevational view thereof;
FIG. 5 is a rear elevational view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The broken lines are for illustrative purposes only and form no part of the claimed design.