After hitting the lowest levels in exactly 2 weeks on Friday, mortgage rates bounced back up toward their recent highs today. This risk was already taking shape by Friday afternoon as the bond markets that underlie mortgage rates had deteriorated throughout the day. When bonds weaken enough during any given day, mortgage lenders are at risk of 'repricing' (revising the day's original rate sheet, effectively raising rates).
Even if bonds had merely held steady overnight, lenders still would have been forced to raise rates a bit today. But bonds managed to lose even more ground overnight, thus making for a more noticeable increase in rates compared to Friday afternoon. The net effect is that the average lender is now somewhere between the 2-week lows seen on Friday and the 7-year highs seen 3 days prior. As always, pricing strategies can vary considerably. Some lenders lost barely any ground because they'd priced more conservatively on Friday. Others are quite a bit higher because their Friday morning offerings were strong.