Hurricane Michael Breaks Records!

Hurricane Michael Nearing Landfall on October 10, 2018  (Source: WUSA9)

Hurricane Michael quickly developed into an intense borderline Category 4/Category 5 storm with sustained winds of 155 mph at its time of landfall yesterday.  Its minimum central air pressure fell to 919 millibars (standard sea level air pressure is approximately 1013 millibars or “mb”).  That means Michael had the third lowest air pressure of any landfalling hurricane in the United States and the fourth highest sustained winds speeds.  Michael became the strongest hurricane to ever make landfall in the Florida panhandle.  

Only three major Category 3 hurricanes (sustained winds of 111 – 129 mph) have made landfall in the Florida panhandle since 1950.  However, the Gulf Coast and inland areas are significantly more developed now than they were during past storms, making the potential for damage with Hurricane Michael significantly higher.  The three previous hurricanes (Dennis 2005, Opal 1995 and Eloise 1975) each caused enough damage to have their names subsequently retired by the World Meteorological Organization (WMO).

 

Unlike Dennis, Opal and Eloise that all weakened before making landfall, Hurricane Michael continued to intensify.  From the time Michael became a hurricane on Monday, October 8 at 11:00 a.m. (Eastern) with sustained winds of 75 mph and a minimum air central air pressure of 982 mb, it continued to intensify over the next 51 hours until it made landfall at 2:00 p.m. Eastern time October 10 with sustained winds of 155 mph and a minimum central air pressure of 919 mb.  A drop of 63 millibars and increase of 80 mph in just over 48 hours is a relatively fast rate of intensification. 

Its rapid strengthening is an important consideration since the evacuation zone for a Category 4 hurricane is much larger than for a Category 1 or 2 storm.  Naturally, larger and more widespread evacuations take more time.  That underscores the need to have hurricane preparation plans in effect at the start of each hurricane season in June.

According to weather records that date back to 1851, a total of four Category 4 hurricanes have made landfall in the United States during the month of October, with the most recent being Hurricane Hazel in 1954.  Hazel had previously been the strongest October hurricane to make landfall with sustained winds of 130 mph a minimum central air pressure of 938 millibars.  However, Michael was much stronger than Hazel at peak intensity that was reached shortly before making landfall yesterday. 

Some may recall that Hurricane Irma was a Category 4 when it made landfall in southwest Florida in September 2017.  But, Hurricane Michael was more intense with higher sustained winds and a lower air pressure.  Sometimes, there is a lag time between a very low air pressure and a commensurate increase or decrease in the sustained wind speeds of a hurricane.

Overall, Hurricane Michael’s track was well-forecast as it was expected to track northward into the eastern Gulf of Mexico.  However, given Michael’s rare intensity at landfall it will take weeks if not months to measure its impacts both on the Gulf Coast and the southeastern United States.  It’s all but certain that for a third straight year the Atlantic Ocean will have an “M” storm retired.  Hurricanes “Matthew” in 2016 and “Maria” last year both saw their names subsequently retired.

Strongest Landfalling Hurricanes in Continental United States by Air Pressure (millibars or "mb")

Source: National Hurricane Center

1.  Florida Keys Labor Day Hurricane (1935) – 892 mb
2.  Camille (1969) – 900 mb
3.  Michael (2018) – 919 mb
4.  Katrina (2005) – 920 mb
5.  Andrew (1992) – 922 mb

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Strongest Landfalling Hurricanes in Continental United States by Sustained Wind Speeds (mph)

1.  Florida Keys Labor Day Hurricane (1935) – 185 mph
2.  Camille (1969) – 175 mph
3.  Andrew (1992) – 165 mph
4.  Michael (2018) – 155 mph
5.  Charley (2004) – 150 mph

--> Hurricane Charley was the most recent of five hurricanes to make landfall in the U.S. with 150 mph sustained winds