Most likely Poa Trivialis - it does well in shady, often wetter areas. It is ridiculously hard to get rid of without harming other grasses, and the few herbicides that work are quite expensive.

Look for shallow rooting and lots of whitish root-like things above the ground (stolons). It spreads mostly by those, and they are easily spread around the yard by dethatching and core aeration.

I have experience with poa annua. I am going to assume they behave the same way. The only think that makes me unsure it is pia is the lack of seed heads. If and when you see those, you'll know what I'm talking about and it is definitely poa.

Poa will die off in the heat of the summer because of its shallow roots. Since it is in a shady area, I don't know if that will happen in your yard. I have heard to bag your clippings as that helps the seeds from spreading. I cannot speak to the effectiveness of this. The only thing I can tell you works for sure is a good pre-emergent. I used a leaving product faithfully since last fall and the only poa in my Bermuda lawn is where the grass is thin. Definitely a night and day difference from last year. Sorry as this may not give you much help for what to do to get rid of it this year now that you have it.

Poa Annua and Poa Trivialis are very different from one another, and share few traits other than they are both weedy grasses in lawns.

Poa Annua may "cluster", but the size of the patches ( 1 ft to 3 ft irregular roundish patches) is much more indicative of Poa Trivialis. I'd rather have 5 Poa Annua invasions than 1 Poa Trivialis invasion.

Thanks for the replies so far, this grass/weed has not shown any seed heads and as you can tell in the picture it has grown to a rather large size along the edge of a bed where I got the sample.

So without the seed head, does that point to Poa Trivialis?

Yes. Poa Annua is seeding now, and Poa Trivialis later (and often not at all at lawn heights). So how does it spread if not by seeds? By those stolons forming new plants where they touch the soil. That's why the patches spread outward from the center.

Anyone have any successful ways of getting rid of this? I'm hopeful it will die once the temps get up but what about preventing it next spring? Thanks

Will Celsius kill it?