The U.S. Energy Information Administration has raised its predictions for diesel and oil prices on more optimistic economic growth forecasts, according to the most recent Short-Term Energy Outlook.

The EIA expects diesel fuel retail prices to average $3.05 a gallon in 2010, and $3.20 in 2011, up from the previous forecasts of $2.95 and $3.12 per gallon in 2010 and 2011, respectively. In 2009, diesel averaged $2.46 a gallon.

Diesel prices have been on the rise for the last six weeks, gaining half a cent this week to an average of $3.127 a gallon. Over the last six weeks, diesel has increased 18.8 cents.

The EIA also raised its predictions on oil prices by about $2 a barrel to about $84 a barrel during the second half of this year. In addition, West Texas Intermediate crude oil spot prices should reach $87 by the end of 2011.

In this month's Outlook, the EIA said it does not assume any significant disruptions to energy supply due to the April 20 oil spill at the Deepwater Horizon mobile offshore drilling unit in the Gulf Coast.