What is the impact of the powerful storm that hit the east coast of the United States?

According to ABC, on the evening of November 3th, local time, a powerful storm hit the east coast of the United States, causing more than 13, users to lose power. According to reports, more than 23, users in New York State have lost power. According to the National Weather Service, the storm was still 14 miles west of Dover, Delaware, which triggered a tornado. According to the National Weather Service, the storm was near Goldsboro, Delaware at 3: 2pm EST on November 3th, and it was moving northeast at a speed of 4 miles per hour. As of 7: pm local time on November 3, some states issued tornado warnings, and destructive windy weather may occur in Washington, D.C., Baltimore, Philadelphia and southern New Jersey. Heavy rain and strong winds will spread to the northeast. From the morning of December 1st to the afternoon, the rainfall on the east coast will be completely over, and there will be showers in parts of the Great Lakes in the east, from Pittsburgh to Cleveland to Buffalo. In addition, there may be about 15 centimeters of snow in the mountains of North Carolina. From western New York to North Carolina, relevant departments have issued winter snowstorm warnings.

then why is the east coast of the United States often hit by snowstorms? Let's take a look at the world ocean current model map:

The whole east coast of North America is surrounded by warm currents (Gulf Stream and North Atlantic Stream), but what happens when the warm currents flow through it? Of course, it is warming and humidifying. . . Let's talk about warming first. According to the thermodynamic properties of air, the air expands and rises when heated, so the warm ocean current just provides a heat source, and the air near the ground expands and rises when heated, and a low-pressure system will naturally appear near the ground, which is the formation of a strong low-pressure system. Let's talk about humidification. Warm current will aggravate the evaporation of sea surface, which will bring a lot of water vapor. This is the premise of having a lot of precipitation.

Let's take a look at the topographic map of North America again:

There is no barrier in the Central Plains, and the cold air erupting from the Arctic high in winter can drive straight into and sweep the whole of North America (because the high pressure always moves towards the low pressure), so what happens when the cold air from the Arctic meets the warm and humid east coast airflow? Nature is a blizzard that swept across North America!