I'm no help with the poa issue. As far south as I am it is not much of an issue. I see it in the lawn, but only for a few weeks (long enough to go to seed, though).

Overseeding KBG? Why? Especially when it's as dense as yours seems to be?

I think you're watering too frequently...unless your temps are running over 110 degrees F.

Watering: Deep and infrequent is the mantra for watering. This is for all turf grass all over the place. Deep means 1 inch all at one time. Put some cat food or tuna cans around the yard, and time how long it takes your sprinkler(s) to fill all the cans. Memorize that time. That will be the time you water from now on. My hose, sprinkler and water pressure takes 8 full hours to fill the cans. Your time will likely be less. I like gentle watering. As for watering frequency, that depends on the temperature. With temps in the 90s, deep water once per week. With temps in the 80s, deep water once every 2 weeks. With temps in the 70s, deep water once every 3 weeks. With temps below 70, deep water once a month. Note that you have to keep up with quickly changing temps in the spring and fall. This deep and infrequent schedule works in Phoenix and in Vermont, so it should work for you. The reason for deep and infrequent is to grow deeper, more drought resistant roots and to allow the soil to dry completely at the surface for several days before watering again. If it rains, reset your calendar to account for the rainfall.

There's a very small chance you have clay. Are there brick factories nearby? If not you probably don't have clay. It is much more likely you have a soil with an imbalance of salts like calcium, magnesium, sodium, and potassium. That can be corrected once you have a good soil test (Logan Labs $25 is the test you need). You can see for yourself whether you have clay by doing a jar test. Find a clear container, fill it half way with soil, fill it the rest of the way with water and a few drops of soap. Measure up the side with a ruler and take a picture to see how many inches of soil you have. Then screw the top on the jar and shake it like crazy. Set the jar down with the ruler next to it. At 2 minutes take another picture. At 2 hours take another picture. At 2 days take another picture. The material that has settled after 2 minutes is sand and gravel. After 2 hours you'll get the loam. At that point if you can see through the water on top so that you could read something held on the other side of the jar, then you have zero clay. Everything that will settle will settle by 2 days. Suspended clay particles will still cloud the water after 2 days. Then you can use the measurements of settled material in your pictures to determine the proportional content of your soil (sand versus loam versus clay).

Zones are only used to select plants for winter hardiness. Once you pick a plant, then the zone is meaningless for care. For example I think Oregon has most of the zones except 9 and 10. But I would not think to grow bermuda there.

That does not look like poa annua to me. Unless you have a disease or something drastic happens to your lawn, it does not need overseeding. There is nowhere for new grass to grow (the old grass would shade out the seed and outcompete the new). Here is a website to help you identify the grass.

+Above. That doesn't look like P. annua, but I'm terrible at weed ID.

Plus your lawn is already nicely dense, it just needs to fill in. Overseeding probably won't help very much as there's nowhere for the stuff to grow.

It's a little hard to tell, but the color and lay of the grass implies that it's now getting to the point where it wants a good feeding. It's the correct time for you, so have at...

Thanks to all for the comments.

Dchall_san_antonio - when I rake out the dead blades, it seems the grass is actually a bit thin, so thought overseeding might help, even thou the KBG is a spreader. Maybe that's just me being impatient. As with most other lawn issues, proper time, maintenance and care will most likely be the best thing for my lawn in this instance. As to the watering schedule, I had been weaning it back the last year and a half. It seemed that it would get stressed easily when the temps went up, more so than some other lawns in the area, most likely because for the first couple years, I was doing the opposite of what you suggest, which is long, infrequent waterings. I would water every 3rd day. I thought the water was just staying in the top soil and not making the grass "work" for its water. But I like your schedule... fairly easy to remember. And starting fresh with your schedule in Spring will hopefully help the lawn ease into it.

As for the jar test, I've read about that, but never done it. I have one question though. Knowing that I have good, black dirt that came with the sod, should the sample come from below that (roughly 1" down) or should the sample include the good dirt that came with it. I'm not sure which way is better, with both probably giving slightly misleading results. And the soil test, I had seen that recommendation quite a number of times, and seems to be a worthy investment. It looks like the recommendation is to take samples from 6" below grade in different areas, mix and submit one sample. Seems easy enough.

Beckyinrichmond - that site is exactly what I was looking for but couldn't find! Thank you! It would seem that this an annual rye grass. I haven't researched yet to see what its habits are and if it is anything that can be controlled, but it looks different enough that it bothers me (and probably shouldn't). My youngest said the lawn looked polka-dotted... I couldn't disagree.

Morpheuspa - it had a feeding a couple weeks prior, but didn't green up like a lot of the lawns did. However, in the last few days since the pictures, it's been damp and cool (highs in mid-60's) and the grass has taken off greening up. I will actually be interested to see what happens this year by not using chemicals to feed. I have been reading some about using alfalfa to feed, and I'm thinking of testing that on a small area. Somewhere on GW, I saw pics that were pretty amazing.

Again, thanks to you folks for the comments, suggestion and guidance.