Southwest fares adjust VERY differently than other airlines. Other airlines go up and down based on the day, the time, and by how many people are checking and viewing the flights on sites like Kayak and Orbitz. Southwest doesn't use these crazy formulas. Typically they have a set number of seats in each fare class. Say the plane holds 100 passengers. Your best fare would be one of the first people to book. Once x number of seats are filled, they up the fare. They do it again when another X number of seats are filled. Southwest gets more expensive as the flight get closer to being fully booked.
I just booked my airfare, but avoided southwest because they don't have direct flights for me, but that's too bad because I hate paying bag fees. I was able to secure US air for $170 direct one way cross country. Good luck. If you have a smartphone, get the app and set your ding alerts. If not, set them on your computer.
Any thoughts of booking a different airline and flying separately and meeting up?