(Minneapolis, MN)  —  Officials with Minneapolis-St. Paul International Airport are urging passengers to be flexible and patient with their travel plans.  A weather system bringing heavy snow, white-out conditions, and bitter cold is hitting the state today and will last through Friday.  Conditions will likely mean flight delays and cancellations.  Airlines are asking passengers to check their flight status before coming to the airport.  Today and tomorrow are the busiest travel days of the December holiday season.