A powerful storm system that can resemble a hurricane but derives its energy from non-tropical sources is known as a nor’easter.
These cyclones typically occur during the autumn and winter months and can produce everything from heavy precipitation and damaging winds to rough surf, coastal flooding and beach erosion.
Although nor’easters are most commonly associated with regions such as the Northeast and mid-Atlantic, their impacts can extend into Florida, where damaging winds, coastal flooding and severe weather can create hazardous conditions.
While there is no official threshold that defines what a nor’easter is, all systems must produce northeasterly winds around a center of low pressure.
The eastern seaboard often provides an ideal breeding ground for these systems because of the temperature contrast between cold continental air and the warmer waters of the Gulf Stream.
The structure and intensity of a nor'easter can vary significantly, but the storm systems are always within a few hundred miles of the densely populated Interstate 95 corridor.
It is also important to note that meteorologists at National Weather Service forecast offices do not use the same criteria when determining whether a low-pressure system qualifies as a nor’easter.
Some offices across the Northeast U.S, may place greater emphasis on snowfall accumulations, while others across Southeast may focus on characteristics such as coastal impacts.
Nor’easters also do not have dedicated alerts, unlike the specific watches and warnings issued for tropical storms and hurricanes.
Instead, NWS forecasters issue alerts based on specific hazards such as high winds, coastal flooding, rip currents and other hazards.
One of the most memorable nor’easters to affect Florida was the March 1993 “Storm of the Century,” which produced hurricane-force wind gusts, tornadoes and flooding across the state.
Damage over the eastern United States was estimated to be at more than $5 billion.
Another example of a memorable nor'easter was the Christmas Snowstorm of 1989, which produced heavy frozen precipitation across the Southeast.
Measurable snow fell as far south as Jacksonville, St. Augustine and Tallahassee, while flurries were reported around Tampa and Sarasota.
The storm system also helped to usher in dangerously cold temperatures, causing significant damage to the citrus industry.
Because not all nor'easters are built the same, meteorologists classify the storm systems using the Miller classification system, named after researcher J.E. Miller, from the 1940s.
Originally, only two types of storms - Miller Type A and Miller Type B - were used for identification purposes, but over time forecasters have expanded the system to include three additional set-ups: Type C, Type D and Type E.
Both the 1989 Christmas Coastal Snowstorm and the 1993 Superstorm were considered to be Miller Type A systems, which are often some of the most impactful not only across the U.S. but also in Florida.
Miller Type B storm systems involve a low-pressure system over the Tennessee Valley and Appalachians, along with a secondary area of low pressure off the Southeast coast. This pattern typically leaves much of the Sunshine State free from experiencing hazardous impacts.
The frequency of nor’easters tends to diminish in April, as the influence of jet streams weakens and temperatures start their rebound into the warmer summer months.
