January heating oil prices traded as much as 2.0% higher this morning but has been unable to penetrate yesterday's high like its peers in the crude oil complex. It seems that some of the added weakness came from heavy selling pressure in the Midwest cash diesel market yesterday. This comes after EIA data showed a surge in US distillate stocks at the same time that demand has slipped. Also adding to the downside momentum yesterday were reports that a large Illinois refinery had returned to full capacity.