Putting in 2 cents before sending you to the lawn forum ... Weeds, like many plants, have life cycles. The one you're displaying looks like an annual that has come, or is coming, to its life's end. Lawns can have large infestations of weeds. When they do, and a given weed has come to its end, it can turn large infested areas brown since there is actual little grass in those areas. It is mostly dead or dying weeds. It is common for weed infestations to show themselves when weather changes, as it may bring about the weed's end. Drought, age or other conditions can do it, too.

Thanks for your compliments. Honestly, that arrangement WAS effortless. I did it outside as I deadheaded. Golden Buddha and partner, clematis ‘Franziska Marie’ are looking too nice not to share today. I just love all the dark to light color progressions Golden Buddha’s blooms go through. Felicia is really blooming well. A little spotty from the rain, but still pretty. Felicia’s blooms have a special sheen to them, impossible to capture with my phone camera. Carding Mill A nice new cane coming up in the middle of Carding Mill. Lisa

I've had lots of problems with earwigs this year. Marigolds, Dahliias, and Eggplants, have been getting munched

I was probably a Monarch caterpillar. They often leave their milkweed and start roaming. That's probably what happened, or a predator got it when it was still on the milkweed.