My past few experiences flying out of BWI were all late afternoon flights on WN. The security line for Pier B was incredibly long each time, manned by "cream of the crop" TSA screeners with crappy attitudes.
Not knowing what it's like for your departure time, I would allow at least 1 hour for screening at Pier B.
BTW, welcome to FT! Your answers may not be what you wanted, but they're usually spot-on!
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Other than that, Mrs. Lincoln, how was the play?