As Hurricane Rita moved into the Gulf of Mexico Wednesday, Sept. 21, providing yet another threat to oil rigs and production facilities there, prices for crude jumped to their highest levels in three weeks.

On the New York Mercantile Exchange, oil surpassed $68 a barrel in midday trading as investors worried about the effects of the hurricane on oil supplies from the Gulf as well as refineries in Texas.

Diesel prices, meanwhile, were holding their own on Wednesday.

ProMiles reported a national average diesel price of $2.762 per gallon. That’s up less than a penny from the day before. Only Washington state, Idaho and California posted averages higher than $3 per gallon.

Just how long those prices would hold is anybody’s guess. Hurricane Rita appears to be headed straight for the Texas coast, and Texas has about a quarter of the refining capacity in the United States, according to Reuters.

The U.S. Department of Energy released a report on Wednesday stating that the nation’s inventory of distillate fuels – which include heating oil and diesel – is about 5 percent higher than it was at this time in 2004.

That news kept prices from skyrocketing to new highs, but analysts say they don’t know how long that calming effect will last.