National Grid is warning customers that they will see a significant increase in their electricity bills beginning in November.

The company recently filed with the state to adjust rates for the winter and says bills could rise by 37 percent because of higher power supply prices — which the company describes as "the cost of the electricity National Grid buys for customers and passes on without a mark up."

"Because that commodity has increased in price so much, customers are going to see a significantly higher bill this winter than they did last winter," National Grid spokesman Jake Navarro told WBUR. "For a typical residential customer, who uses 500 kilowatt hours a month, we're talking about a $33 impact to their electric bill. That's definitely a significant increase."

National Grid's gas rates, however, are expected to be slightly lower this winter. The company filed to reduce that rate by 1 to 3 percent.

The Boston area is serviced by both National Grid and NSTAR. We've reached out for rate information from NSTAR, but have yet to hear back.