What is rapid intensification and why did that happen to Hurricane Idalia?

Hurricane Idalia gained strength quickly while moving over Gulf of Mexico

Rapid Intensification

ORLANDO, Fla. – Before Idalia came to be, it was an area of low pressure off the Pacific Basin near the Central America coast. It became Tropical Storm Idalia on Aug. 27, 2023, when Hurricane Hunters found winds of 40 mph. As Tropical Storm Idalia moved to the north over the Yucatan Channel, it continued to intensify as forecasters expected.

After passing west Cuba on Aug. 29, 2023, the storm strengthened into a Category 1 hurricane. Later that day, as Idalia continued to move to the north it continued to strengthen. By the afternoon of Aug. 29, 2023, it reached Category 2 strength.

Conditions were “prime” for further strengthening meaning sea-surface temperatures were well above 82°, little to no wind shear and a ton of Gulf moisture for Idalia to grow and rapid intensification was expected due to these factors.

While moving over the eastern Gulf of Mexico it reached Category 4 strength during the early morning hours on Aug. 30, 2023. Maximum sustained winds were measured within Idalia of 130 mph.

Idalia intensified from a Category 2 storm with winds of 100 mph then overnight to a Category 4 hurricane with winds of 130 mph, meeting the rapid intensification threshold.

Rapid Intensification

But exactly what is rapid intensification? In short, rapid intensification is when maximum sustained winds have increased by 35 mph in over a 24-hour period. And Hurricane Idalia did just that.

Before making landfall on Aug. 30, 2023 at 7:45 a.m. near Keaton Beach, Florida, it weakened slightly to a Category 3 hurricane packing winds of 125 mph. The intensification came to a brief halt due to a process called eyewall replacement.

During eyewall replacement within the core of a tropical system, the inner eyewall is replaced by an intensifying, contracting outer eyewall.

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About the Author:

Michelle joined News 6 as a meteorologist in May 2023.