It often happens thus. Because most airline fare analysts don't work on holidays or weekends, that's when one airline will call their people into work and launch a sneak sale. So it appears that Southwest has launched a sale today for travel Jan 15-Apr 30 and purchase through Jan 19. The lowest fares are for travel Tue/Wed with a 14-day advance purchase, but not for travel to/from Florida (where we most want to go!), or to/from Washington or Orange County/Santa Ana.
But the other airlines have responded and are actually offering better deals on many routes, and are adding new low fares to/from airports near Southwest's, and are also including Washington and Florida!
Also, the other airlines are offering the same or even lower fares for a longer travel period in some cases, so don't willy-nilly go booking on Southwest without checking. This is an ok sale, but nothing we haven't seen before. The real deals are on the other airlines, especially for travel after the last validity day of the Southwest sale.
For example, LA to Baltimore. Take a look at Northwest vs. Southwest for travel in May, at $247 RT including tax and a $7 Travelocity booking fee:
But Southwest is a lot more at $393 RT including tax.
This is the usual pattern: Southwest comes out with a sale and the other airlines match or, more often, beat it. Oddly, however, Southwest has several dates of travel on this route for travel as late as early May for $95 each way, even less than the advertised sale. To find the cheapest seats, be sure to use Southwest's "ShortCut" flexible date search tool.