Arlington is closing the Minuteman Bikeway for repairs this week from Hurd Field (Trader Joe's) to Ryder Street (Arlington Recreation Center). Seeing how it's pouring today, with more rain expected tomorrow, I doubt they'll finish on time and there might even be further damage.
Thanks to Jack Johnson of the Arlington Bicycle Advisory Committee for the tip.
Update: Jack reports there's no repair work today. I bet that goes for tomorrow, too.
Update 2: The closure, repairs, and renewed rain are also noted on boston.com.