Ah, we hardy ever fly out of BWI with checked baggage. We usually are home around 1:45. We park in the onsite garage almost always, sometimes we use Fast Park and Relax but I hate shuttles, even though theirs are fast and take you right to your car.
Worst case is always 0"! 2.2" is what I think we settle - won't be surprised if it's closer to 3", won't be surprised if it's weaker and closer to 1". Kinda settling in the middle - I like CTP's 1-3" forecast.