A heavy snow warning has been issued for New York City, forecasting up to 20 inches of snow and advising residents to avoid travel due to hazardous conditions. Meteorologists are tracking an intensifying weather system that is expected to cause significant disruptions to transportation and daily activities. The National Weather Service warns of reduced visibility and slippery roads, urging extreme caution for those who must travel. Snow accumulation is expected to rapidly impact public transportation, including subway and bus services, and cause delays and cancellations at major airports.