Prices have been steadily improving today on a nice even upwards curve. As such, there have been no lock alerts to report. Hopefully you have seen some decent reprices for the better. you should have gotten around a .25 improvement on the day.
The next question is "what will happen next." In this market, the only certainty is uncertainty. We have not seen a predisposition for rates to stay at current levels over the last several months.
Particularly, in the most recent month, each time the 5.5% coupon has crested 100-000, we've gotten chopped down fairly quickly. So if you want to play it safe, locking as late as possible tonight is the way to go.
Over the next few days, we will likely either be rising even higher in MBS or declining rather rapidly. It's unlikely that rates will remain unchanged. If you can afford to take the risk or if you are certain that the upcoming economic data will indicate more weakness coupled with moderating inflation, floating will probably pay off.