Hard to tell by the pic you posted, but I'd guess your lawn is contaminated by common creeping bentgrass. Very disease prone and gets stemmy and brown at residential cut height. In any case, got a closeup?

If it is, I'd use Tenacity and reseed with perennial ryegrass. Fine fescue would work in shady areas but FF does not like Tenacity and you might still need to control the creeping bentgrass going forward.

Yeah, looks like creeping bentgrass. At residential cut height, it will start to lay down and become stemmy and often a scalped appearance. It actually does well where there's a lot of moisture. Doubt that now is a suitable time to seed but I would still spray Tenacity every week until winter to try to kill it. It'll take 3-4 applications.

Perennial ryegrass does not spread so you probably will need to overseed periodically. The good thing is that it can be done in "spread it and forget it" fashion because it germinates and establishes so quickly and easily.

Also, I should add that nimblewill can look a lot like creeping bentgrass but the treatment would be the same: tenacity and reseeding.