What is your normal care routine? How often do you water, how often and how high do you mow, how often do you fertilize and with what? Do you have full sun or is shade involved?

That's weird. I hit the preview button and it posted my incomplete message. I had more questions.

Have you applied any insecticide, fungicide, or herbicide in the past year? If so, what were they?

Weekly cutting to ~ 3.5". I only water to supplement rain to give lawn ~1"/week. When I water, I do deep & infrequent. Last year I fertilized with inorganic w/Dimension just before the lilacs bloomed. Then with Milorganite ~6 weeks later. Then inorganic w/Dimension in the fall to try to head off this spring's poa.

The worst areas are shaded, so things stay somewhat wet (that's where the moss was worst). But, other areas are full sun (maybe a bit of a dip on an otherwise elevated area...maybe another site for water aggregation). The area with dry blades but no clumping is full sun. The area with matted grass that easily pulled up was also full sun.

Definately no fungicide. Two years ago I used grub preventer. Last year I saw no sign of grubs so I skipped it (I have 2 young children, so I was trying to keep pesticides to a minimum.

We had a warmish autumn, so it is possible that when my landscaper stopped cutting my lawn, there may have been a little more growth after that mixed with other conditions to cause these problems. Not a lot of snow, but things have been pretty wet (I'm in the north east, in a suburb of New York City).

Thanks

Sounds like something familiar to me when I bought my house last summer. I had various areas where the grass looked like that. Upon digging up those spots, I found grubs...might not be your problem, but the result sounds similar.

I just realized you checked for grubs and didn't find any. Mine were pretty apparent.