Andy ..."noticed that a SECOND crop is coming in on the vines...
All at once, and very prolific...

The plants are Celebrity, from Home Depot, and this is north Texas
with temps in the 90s every day and almost no rain, tho I have
been watering the garden every other day or so with a sprinkler...

So, learned gurus, is this normal ? Am I going to get tomatoes off
these vines until the snow falls, or is a second crop the most I can
hope for ?

Also, any advice on how to guarantee some fall tomatoes would be
nice...."

Is it normal that N. Tx is 90+ every day, there/s no rain, and you/re
draining your well keeping your garden alive?

It certainly was went I lived in that 'hole 'nuther country!

Determinants, like the Celebrity, set an initial heavy crop, you then
get a smaller second crop and after that, it/s +/- over. This type of
tomat is good if you/re selling for fresh-market b/c you get a whole
lot all at once.

OTOH, indeterminants are more like the Energizer Bunny, provided they
don/t succumb to the elements. With luck, they/ll pick all season
long.

You can be guaranteed a fall crop by setting out 'short-season' plants,
such as Early Girl, again in early July. My zone-7 seedlings are 4"
tall and ready for hardening-off. EEBE, they/ll start picking by
mid-September.