Here are some photos of what I am trying to describe.

Looks like the skin split then a secondary rot entered.

Remedy:
1. Evenly moist is the goal for soil (or potting mix).
2. Pick if split, and eat soon.

I checked on these guys a couple days before this happened. One had a dark line under the skin, but no sign of breakage. Skin was soft in the area however.

When I removed the first tomato of this cluster, I checked the others in the same grouping (tomato in photo was one of them)..They looked fine.

The pictured tomato gave no evidence this would happen until I noticed it this morning. Both tomatoes were next to each other. Spots showed on opposing sides.

This summer has been a wet and humid one..is this any sort of virus or just some sort of fluke brought on by this summers conditions?

Anything??? Anyone???

Have you had windy or stormy weather that could have banged the tomatoes against each other?

One year when I had my small potted lemon tree out on the deck during the summer, there was a bad storm. A few days later, the larger of its two fruit began to turn yellow with odd rapidity.

Then it vanished!

That was the very first ripe lemon, so I was particularly unhappy. Raccoon, maybe? No, it had fallen onto the deck and was rotten on one side.

I decided the storm had banged the lemon into the side of the pot, the skin had been injured, and it had rotted.

No, not a virus.

I don't know it's possible, the weather has gone from one extreme to another. As I said, there was another tomato in the same cluster like this.

I was thinking too much moisture or something gathering and sitting for too long in between the tomatoes. stem and vine.

I thought I avoided anymore like this when I took off the first rotting one. This second one was looking perfect until yesterday.

I guess as long as it's not a virus, I should be happy..I just don't want to lose too many of them to something like this.

Moisture can cause a tomato to split once it's begun to ripen -- but it wouldn't split in a straight line like that. I think the operative condition is the contact with the other tomato. Then the rot spread along the locule.