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

According to ABC, on the evening of October 30th, local time/kloc-0, a powerful storm hit the east coast of the United States 165438, causing more than130,000 users to lose power. It is reported that more than 23,000 users in New York State have lost power. According to the National Weather Service, the storm is still 14 miles west of Dover, Delaware, causing a tornado. According to the National Weather Service, the storm was located near Goldsborough, Delaware at 3: 20 pm EST1October 30, and moved northeast at a speed of 40 miles per hour. As of 7: 00pm local time (165438+1October 30th), some states have 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. 65438+February 1 In the morning and 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 cm 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 pass? Of course, it is heated and humidified. . . Let's talk about warming up 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. When the air near the ground expands and rises when heated, a low-pressure system will naturally appear near the ground, which is the formation of a strong low-pressure system. Let's start with humidification. Warm current will aggravate the evaporation of the sea surface and bring a lot of water vapor. This is the premise of a large amount of precipitation.

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

There is no barrier in the Central Plains, and the cold air burst from the Arctic high in winter can sweep across North America (because the high pressure always moves to the low pressure), so what happens when the cold air from the Arctic meets the warm and humid east coast airflow? Nature is a snowstorm sweeping across North America!