Based on Hurricane Florence's Location, We Didn't Expect It to Get So Strong So Soon

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Rapid intensification refers to an increase in wind speed of at least 35 mph in 24 hours or less. Florence met this criterion Tuesday into Wednesday when its maximum sustained winds increased 45 mph midday Tuesday to midday Wednesday. 

Florence intensified further and become a Category 4 hurricane with maximum sustained winds of 130 mph Wednesday evening in a surprising location, as Richard Dixon, a meteorologist at CatInsight, noted. 

Major hurricanes do not usually form so far north and east in the Atlantic Ocean. Florence is the furthest north Category 4 hurricane east of longitude 50W on record, according to Sam Lillo, a meteorologist at the University of Oklahoma.

However, before satellites came into use in the mid-1960s, it's possible that hurricane strength was underestimated and that there were other Category 4 storms in this area.

Overall, the intensity forecast for Florence has been a challenge. 

Late Tuesday morning, Florence became a hurricane and remained a Category 1 hurricane through 5 p.m. Tuesday. Florence continued to strengthen and became the first major hurricane, Category 3 or higher, of the season in the Atlantic on Wednesday morning.

The images above capture Florence from when it started as a Category 1 hurricane on Tuesday evening until it reached Category 4 status on Wednesday evening. The structure changes are clearly seen with its eye becoming more defined.

As Lillo noted, moderate to strong wind shear has been in place just to the north of Florence. Wind shear, which refers to a change in wind direction and/or speed with height, typically hinders tropical cyclone development since it can disrupt the circulation or core of the tropical cyclone. 

Wind shear increased Thursday. This caused Florence to weaken and lose its symmetry.

(MORE: Why Some Hurricanes Rapidly Intensify and Others Do Not)

In addition, sea surface temperatures have been relatively cool where Florence has tracked.

Tropical cyclones usually need water temperatures to be above 26 degrees Celsius (79 degrees Fahrenheit) to form and flourish. Sea surface temperatures have been slightly below average in the region of the Atlantic where Florence is located and have been just below 80 degrees.

Dry air has also been prevalent near Florence. Dry air is another factor that usually limits tropical cyclone formation and strengthening.

On Thursday, dry air was infiltrating Florence leading to reduced convection on its southern side. 

Given Florence's small size, wind shear and dry air had a strong influence Thursday. Florence quickly weakened, a contrast to its rapid intensification just 24 hours earlier.