In this satellite handout image provided by National Oceanic and Atmospheric Administration (NOAA), shows the entry of a large area of low pressure, from the Polar Vortex, into the Northern U.S. January 6, 2014. The weather system is bringing dangerously cold temperatures not seen in half of the continental United States in about 20 years. It is expected to move northward back over Canada toward the end of the week. - 

Managers of the electricity grid supplying customers from the Midwest to the Mid-Atlantic to the South are asking people to conserve energy, when prudent today, as the extreme cold weather spreads. JetBlue, which canceled all flights out of New York and Boston yesterday, is flying again this morning. The dangerous cold is also causing money to shift in other ways. Meteorologist Chris Orr, editor of the Weather Trade Newsletter, which does forecasts for industry, explains to Marketplace Morning Report host David Brancaccio. Click the audio player above to hear the story.

Follow David Brancaccio at @DavidBrancaccio