Crude oil futures tumbled below $48 a barrel yesterday, closing at their lowest level in seven weeks, on rising expectations that the U.S. supply of transport and home-heating fuels will be adequate this winter.

Light crude for December delivery dropped $1.72, or 3.5 percent, to settle at $47.37 per barrel on the New York Mercantile Exchange as traders awaited the U.S. government's upcoming petroleum supply report. It was the cheapest closing price since Sept. 21, when Nymex oil finished at $47.10 per barrel.

While oil prices are down roughly 14 percent from the Nymex settlement high of $55.17 late last month, relief at the retail level might not come soon enough for consumers, according to the Energy Department, which yesterday raised its earlier estimate for home heating costs over the next five months.

Analysts also said it was too soon to definitively say the worst is over for fuel-hungry motorists, homeowners and businesses.

"That's the question. Is this uptrend over?" said Tom Bentz, a broker at BNP Paribas Commodity Futures in New York.

"I'm not convinced yet that the highs are in. They could be," Bentz added, "but I'd like to see some more evidence" that the nation's supply of crude and heating oil will be sufficient this winter.

An important set of evidence will be revealed to the market today, when the Energy Department releases its weekly petroleum supply data.

Traders appeared to be betting yesterday that the data would show increases in domestic inventories of crude oil and distillate fuel, which includes heating oil, diesel and jet fuel.

James Cordier, head trader at Liberty Trading Group Inc. of Tampa, Fla., said today's supply report -- and, perhaps more importantly, the market's reaction to it -- could "decide energy prices for the rest of the year."

The Energy Department predicted yesterday that residential heating oil costs would average $1.88 per gallon in the October-March period, an increase of 37 percent from a year ago. At the start of last month the agency had forecast a 28 percent increase, but that was before oil prices surged above $55 a barrel.

Heating oil for December fell 2.44 cents yesterday to settle at $1.342 per gallon, while natural gas dropped 12.9 cents to $7.471 per 1,000 cubic feet. Gasoline futures slipped 4.14 cents to $1.2339 per gallon.

In London, Brent crude for December delivery plunged $2.21 to $43.71 per barrel on the International Petroleum Exchange.