Does availability ever improve?
 

Do cheaper flights that say unavailable now ever come available?

Don't know....
 

but welcome to Flyertalk!

Welcome to FT.

Yes, availability sometimes (maybe 20% of the time I've tried) improves between 12 and 8 weeks before your travel date. This is unlikely to happen for Friday or Sunday evening flights or for any other flight that Southwest expects to sell out. If you want to travel at a peak time, don't expect the lowest fare no matter when you buy.

Yes - sometimes. But you shouldn't count on it happening. The common wisdom around here is to book the flight you need at the best price you can get now, and then keep watching it and if it goes down apply the full value of your original ticket to the new one and pocket the difference as a 1yr travel credit that can be used for future flights (assuming the original fare was not refundable). This is a big benefit of Southwest's lack of change fees (although some other carriers let you reprice and get a voucher, but not with the ease of Southwest or with the ability to change to a different routing or day).

Yes. This happened to me just last week. I had purchased OAK-PHX tickets from the Fun Fares and Advance Purchase buckets the morning the schedule opened for Thanksgiving travel as those were the cheapest available seats. The evening of seven days out from the day of travel, 8+ seats on my flight became available in the Internet One-way bucket. They had not been available that morning, nor had anything cheaper been available prior to that since the original booking.

My second
 

Thanks everybody! ^