Just a few weeks after the devastation wrought by Hurricane Helene, Florida is once again under threat as Hurricane Milton heads towards the state. The latest forecasts predict that Milton will make landfall south of Tampa Bay in the early hours of Thursday October 10 (local time), bringing with it the potential for widespread destruction. The National Oceanic and Atmospheric Administration (NOAA) has placed much of the state under hurricane warnings, emphasizing the severity of the impending storm.
Figure 1: (Oct. 8, 2024) Hurricane Milton, a Category 5 storm at the time of this photograph, is pictured in the Gulf of Mexico off the coast of Yucatan Peninsula from the International Space Station as it orbited 257 miles above. Image source: NASA.
Overview
Formed in the Caribbean Sea, Tropical Depression 14 was upgraded by the National Hurricane Centre (NHC) to Tropical Storm Milton on October 4. An emerging area of low atmospheric pressure over the Central United States eventually steered Milton eastward across the Gulf of Mexico. Feeding off anomalously high sea surface temperatures, low vertical wind shear and high levels of relative humidity, Milton underwent rapid intensification on October 7 to become the second category 5 hurricane of the season, following Hurricane Beryl in June.
At its peak intensity on October 8, Milton had a minimum sea level pressure of 897hPa and maximum sustained winds of 180 mph – making it the 5th most intense hurricane on record (NHC, 2024). Whilst Milton is expected to transition to a category 4 storm before making landfall (NOAA, 2024a), the impacts are expected to be severe.
What makes Milton unique
Hurricanes with a minimum sea level pressure dropping below 900hPa are exceedingly rare. Milton is just the sixth Atlantic hurricane to do so, and the first since Hurricane Wilma in 2005. Equally remarkable is the speed at which Milton intensified. Rapid intensification is defined as an increase of 35 mph in 24 hours. During this phase Milton intensified by 90 mph in 24 hours. (New York Times, 2024) This extreme rapid intensification is difficult for numerical weather prediction models to capture accurately, which can hinder preparation efforts for communities in a hurricane’s path.
How does Milton compare to Helene
Despite early predictions of an active 2024 hurricane season (NOAA 2024b), the Caribbean has seen fewer storms than expected. Whilst it is not unusual for Florida to be at risk of hurricanes in October, the presence of Milton and two other hurricanes (Kirk and Leslie) in the Atlantic means we are currently seeing the peak in the 2024 hurricane season a month later than normal.
Given the recent impact of Hurricane Helene (JBA, 2024), it is unsurprising that comparisons between the two are being made. Helene made landfall further to the north, in Perry, whereas Milton is expected to strike just south of Tampa Bay. Both hurricanes reached category 4 upon landfall. After landfall, Helene moved north and inland, causing significant flooding from high levels of precipitation in western North Carolina amongst other places. In comparison, Milton is expected to move straight across central Florida, exiting to the Atlantic by Friday morning. Milton’s swift travel across Florida may shorten the duration of heavy rainfall over inland areas, but severe precipitation-driven flooding remains a significant concern. As with Helene, both heavy rainfall and storm surge from Milton are likely to cause substantial damage.
Figure 2: Peak Storm Surge Forecast for Hurricane Milton, Wednesday October 9, 2024: 11 AM EDT Advisory 18, NWS National Hurricane Center. Image source: National Hurricane Center.
Our Event Response team will continue to track and assess the impacts of Hurricane Milton over the coming days. We will produce an event report and flood footprint to support our clients in understanding this event.
References
JBA, 2024. Hurricane Helene: September 2024. Available at https://www.jbarisk.com/products-services/event-response/hurricane-helene-september-2024/
National Hurricane Center (NHC), 2024. Hurricane Milton discussion number 12. Available at https://www.nhc.noaa.gov/archive/2024/al14/al142024.discus.012.shtml?
National Oceanic and Atmospheric Administration (NOAA), 2024a. Milton resources. Available at https://www.noaa.gov/milton
National Oceanic and Atmospheric Administration (NOAA), 2024b. NOAA predicts above-normal 2024 Atlantic hurricane season. Available at: https://www.noaa.gov/news-release/noaa-predicts-above-normal-2024-atlantic-hurricane-season
New York Times, 2024. Here’s How Fast Hurricane Milton Intensified. Available at https://www.nytimes.com/2024/10/07/weather/hurricane-milton-intensity-speed.html