This is more of a heads-up than a true reprice alert although risks can't be ruled out completely.  Bonds have drifted away from their best levels of the day after the 30yr bond auction and again after the 3pm CME close.

MBS are still up 10 ticks (.31) in 5.5 coupons but down more than an eighth from mid-day highs.  10yr yields are still down nearly 9bps at 4.20, but that's up from lows of 4.166.

Aggressive, jumpy lenders could consider negative reprices if they priced near the morning's best levels or repriced for the better earlier in the day.  That's a small group though.  The better way to use this alert would be a lock cue for those who were already planning on locking today.