My A/c Central unit is Blowing warm air again. It does it about once a Monthand I turn it off for approx 30 minutes and it starts cooling again. Could this be from the extreme heat ( 100-105 degrees ) here in Texas ? Or possibly the unit not Big enough to cool the Home but was working fine until recently.

Your unit is not intermittent enough to find out what the problem really is.

It could be many items and since it only does it once a month it will be near impossible to figure out. Eventually the defect will show up as time goes on and then you will be able to find the problem.

The unit could be slightly overcharged.
The compressor could be going out on the internal overload.
The possibilitys are endless when you have a once a month problem like you have.

BTW the A/C unit should run in 100-105 degrees with no problem BUT it is possible that the increased heat is causing the unit to run to high a head pressure which can cause problems.

If I may suggest you probably need to clean or have cleaned the outside unit. Dirt in the coils can cause high head pressure also along with the associated problems it brings.