Meteorologists forecast a major winter storm, potentially intensifying into a nor’easter and a bomb cyclone, for parts of the East Coast this weekend. The storm is expected to bring heavy snow, gusty winds, and coastal flooding, rapidly intensifying along the Atlantic Coast. Several inches of snow are anticipated for much of North Carolina and southern Virginia from Friday night through the weekend.
Blizzard conditions are considered likely in some areas due to strong winds and low visibility.
Understanding Key Meteorological Terms
What is a Bomb Cyclone?
A bomb cyclone is a powerful low-pressure system that intensifies rapidly through a process called bombogenesis.
This occurs when a storm's central pressure drops by at least 24 millibars within 24 hours. A millibar is a unit meteorologists use to measure atmospheric pressure. Low-pressure systems are areas where atmospheric pressure at sea level is lower than the surrounding regions. When winds converge, they rotate in the same direction as the Earth, forming a cyclone. This circulation lifts air, leading to moisture condensation and precipitation. Lower pressure within a cyclone indicates a more intense storm.
What is a Nor’easter?
A nor’easter is a large, intense low-pressure system capable of producing heavy rain, heavy snow, severe coastal flooding, or blizzard conditions in the Eastern U.S.
These storms typically form along the Atlantic Coast and move northward or northeastward, as defined by the National Weather Service.
Difference Between a Bomb Cyclone and a Nor’easter
A bomb cyclone describes the rate at which a storm strengthens, specifically its rapid intensification. In contrast, a nor’easter refers to the geographic location of the storm's formation and its general movement pattern.
It is possible for a nor’easter to be classified as a bomb cyclone if it undergoes sufficient intensification, leading to heavier precipitation and stronger winds than a more slowly developing storm.
Historical Examples of Severe Bomb Cyclones
The U.S. has experienced several extreme bomb cyclones:
- March 1993 "Storm of the Century": This event brought blizzard conditions, hurricane-force wind gusts, and coastal flooding from the Gulf Coast to New England. It resulted in over 300 fatalities, more than 10 million power outages, and damages exceeding $5.5 billion.
- January 2018 Storm: This storm rapidly intensified off the Southeast coast, impacting parts of the Mid-Atlantic and New England with heavy snow, damaging winds, and record coastal flooding. It caused at least 20 deaths and an estimated $1.1 billion in damages.