Remember last week's line for cheap gas?. Look for another line today.

Petroleum Analyst Patrick Dehaan at Gas Buddy dot com predicts another gas spike by the end of the day.

"This will be price hike number 19 for the year, bringing the price to $3.99 a gallon."

Why the price spike? DeHaan says gas stations weren't making a profit on gasoline at 3.79 a gallon. The good news, prices won't stay there for long.

"If you are stuck with an empty tank and staring at a gas station with prices at $3.99 a gallon, just wait. Prices will start coming down just as they always do after a price hike."

For those who like to see the tank half-full, gas prices at this time last year were paying around $4.29 a gallon.