I'm stumped on this one ... as I've tried to compare growing patterns with the forum and it doesn't quite fit the crabgrass. quackgrass or fescue clump category as it's not really concentrated in one area or does fan out from one central root. But the thicker stalk seems to resemble. It shows up as bright yellow on my lawn and isn't spotty, but just blankets sections. On the other side of my lawn it seems to have uniform spread across 80% of my lawn. I've never seen these before in previous years and hoping with the warmer summer coming, it will naturally die off if I can nurture the regular grass to grow more. Help?
First and last picture looks like a clumping/coarse fescue. Very common in northern blended turfs. Even TTTF will begin clumping heavily under stress and may need thinning (scarifying) and reseeding to keep blade and clump sizes under control. I've found that the texture of older TTTF cultivars can be a challenge if you don't have other grass types to keep regular spacing.
Second picture, with the lime green coloring, looks like a poa (annua) infestation.