"I don't think we'll have enough going into winter," said John Kilduff, senior vice president of the energy risk management firm FIMAT USA.

During the warm spring and summer months, natural gas producers store, or "inject," as much natural gas as possible. Storage levels seemed sufficient going into the start of the injection season, but after a hot summer when power generators worked at full capacity and two hurricanes struck the heart of oil and natural gas production in the Gulf of Mexico, inventory levels dropped precipitously.

Weeks after hurricanes Katrina and Rita tore through the area, the Minerals Management Service reported today that nearly 56 percent of all gas production in the Gulf region still remains off-line. Overall, the Gulf of Mexico represents nearly 23 percent of the nation's natural gas production. To date, approximately 10 percent of the natural gas produced yearly in the region has been shut down.

Natural gas producers in other parts of the U.S. have been working to make up the difference, and it's showing. Last week, the Energy Information Administration reported a strong increase in natural gas inventories. The EIA estimated that just over 3 trillion cubic feet of natural gas was currently in storage, slightly above the five-year average.

Melissa Marion of the Natural Gas Supply Association, a trade association that represents natural gas producers, said she expected inventory to be sufficient. "We believe that we will be above the five-year average," she said.

FIMAT's Kilduff is not so sure that inventories will be sufficient. "I don't think we are going to make it and to the extent that we don't, we will be in jeopardy and will have a real challenge on our hands," he said.

Tomorrow's Energy Department report will be crucial as it will be the last one before Nov. 1, the official start of the winter heating season, when inventories will be used more to heat homes and business. If this winter is severe, Kilduff predicts there could be shortages in some regions, extended school closings and even possible interruptions for those industries that volunteer to shut off natural gas usage if it is needed elsewhere.