Ian is Latest Dangerous “I” Storm

 

Hurricane Ian, September 28, 2022 (Source: WUSA9/NOAA)

Hurricane Ian made landfall on Florida's west coast on September 28 as a powerful Category 4 storm with sustained winds of 150 mph and a minimum central air pressure of 940 millibars (mb).  Air pressure is considered a more accurate measure of hurricane intensity than wind speed.  More "I" name storms have been retired by the World Meteorological Organization (WMO) for being destructive or deadly than any other letter (13), with Ian almost certain to be #14.  Here are some of the other significant "I" storms that have occurred in the last 20 years.

Iota (2020): The strongest storm of the active 2020 hurricane season, Iota was just under Category 5 intensity with sustained winds of 155 mph and a minimum central air pressure of 917 millibars (mb).  By comparison, standard sea level air pressure is approximately 1013 mb.  Iota caused widespread damage in Central America after its November 17 landfall.  This was the first time since the 2001 hurricane season that the strongest storm of the season occurred in November.  

Irma (2017): Irma reached Category 5 intensity on two separate occasions.  At peak intensity, Hurricane Irma had sustained winds of 180 mph and a minimum central air pressure of 914 millibars (mb).  Irma left a deadly trail of destruction across much of the Caribbean and made landfall in Florida as a Category 4 hurricane, the first to do so since 2004.  Irma did $59.5 billion in damages (2022 dollars), making it the sixth costliest natural disaster in U.S. history, according to NOAA.  Hurricane Irma also claimed 92 lives in the United States.

Irene (2011):  Irene was the first major hurricane of 2011.  However, it weakened to Category 1 status before its first landfall in North Carolina.  Its impacts were far reaching from the Mid-Atlantic to New England.  According to the National Hurricane Center, Irene remains one of the costliest hurricanes on record in the United States with $17.4 billion in damages (2022 dollars) along with 40 fatalities.

Ivan (2004): Ivan was the strongest hurricane of a busier-than-average hurricane season.  It was also a Category 5 storm that caused significant damage to Jamaica, the Dominican Republic and the Cayman Islands.  At peak intensity, Hurricane Ivan’s lowest air pressure was 910 millibars.  Its highest sustained winds around the center of the storm reached 165 mph.  Fortunately, Ivan weakened to Category 3 intensity before it made landfall in Alabama on September 16.  It caused nearly $31.6 billion in U.S. damages (2022 dollars), according to the National Hurricane Center along with 25 lives lost.

Isabel (2003):  Hurricane Isabel reached peak intensity as a Category 5 on September 11, with maximum sustained winds of 165 mph and a minimum central air pressure of 915 millibars.  Isabel weakened to Category 2 intensity before its landfall in North Carolina on September 18.  Despite weakening, Isabel still claimed dozens of lives and caused major flooding and damage across much of the Mid-Atlantic Region and northeastern United States.  In the D.C. Metro Region, Isabel caused approximately one million power outages and was directly responsible for 17 U.S. fatalities.

A Quiet September Gives Way to a Stormy October

 

Avenel Park, Potomac, Maryland

September 2022 will finish as a drier than average month in the Nation’s Capital for only the second time in the last five years.  There have been long stretches of warm and dry early-fall weather this month with ideal conditions for outdoor activities.  It will finish within 1° of average with cooler than average temperatures today, tomorrow and Friday.

The first half of September was quite warm and rainy.  Only one day was cooler than average through September 15 in the Nation’s Capital, according to NOAA.  High temperatures reached 91° on two days (September 1, September 4).  The Nation’s Capital has ranged between 2 and 9 September days in the 90s every year since 2012.  D.C. coolest temperature this month was 51° on September 24 and again this morning.

Rainfall this month has been spotty, although two days had nearly an inch of rain (September 4: 0.82” and September 11: 0.86”).  That’s accounted for most of the 1.95” of D.C.’s September rainfall.  The Nation’s Capital averages 3.93” of September rainfall according to NOAA.  Dry September’s can sometimes be followed by rainy October’s such as in 2005 when D.C.’s driest September (0.11”) was followed by its rainiest October (9.41”).  More recently, September 2019 (0.25”) was followed by a wetter than average October (6.66”), but one event doesn’t necessarily lead to another. 

Although the 2022 Atlantic hurricane season had a quiet July and August, the tropics have gotten a lot busier this month.  The D.C. Metro Area hasn’t seen any impacts from tropical systems so far this season, unlike recent September’s (2011: Tropical Storm Lee or 2018: Hurricane Florence).  However, that’s expected to change in a big way this weekend as the remnants of Hurricane Ian track northward.  Depending on the exact track, the Nation’s Capital could see appreciable rainfall as October gets underway.

A warmer and drier than average September has little bearing on what the rest of the autumn will be like in the Nation’s Capital.  Although Washingtonians have seen 90° heat as late as October 11, NOAA’s Climate Prediction Center expects near normal temperatures with above average rainfall during the first week of October – largely due to the remnants of Ian. 

Destructive Gulf Hurricanes

 

Hurricane Michael, October 2018  (Source: NOAA)

While Ian’s final track is unclear, it’s increasingly likely that it will be an intense and high impact hurricane.  Ian’s effects will be far-reaching and will impact the United States well inland.  By coincidence, the World Meteorological Organization (WMO) has retired more “I” named Atlantic storms than any other letter.  There are some storms Ian could resemble when it’s all said and done.

Michael (2018): Hurricane Michael was only the fourth Category 5 hurricane to make landfall in the United States.  It was the first to do so since Hurricane Andrew 26 years earlier and it remains one of the few hurricanes that intensified up until its landfall.  Michael reached its peak intensity as it made landfall along the Florida panhandle with sustained winds of 160 mph and a minimum central air pressure of 919 millibars (mb).  Michael was the first Category 4 or 5 storm to hit that part of Florida and did $29 billion in damages according to NOAA (in 2022 dollars).

Charley (2004): A relatively compact hurricane, Charley was the second major hurricane of the 2004 season.  Initially, it was feared that Charley would make landfall in the major urban area of Tampa-St Petersburg.  However, its path shifted and it came ashore south of Tampa near the town of Punta Gorda on August 13.  Like Michael, Charley also made landfall at its peak intensity as a Category 4 storm with sustained winds of 150 mph.  Hurricane Charley did roughly $24.6 billion in damages (2022 dollars).

Opal (1995): Hurricane Opal underwent a period of rapid intensification while over a warm core ring in the Gulf of Mexico.  In less than 24 hours, Opal went from being a minimal hurricane to a strong Category 4 with sustained winds of 150 mph.  Its minimum central air pressure of 916 mb set an Atlantic record for lowest air pressure in a hurricane that didn’t reach Category 5 intensity.  Although Opal weakened to Category 3 intensity before its October 4 landfall in the Florida panhandle, it was still quite destructive and deadly with several dozen fatalities.  Opal’s remnants brought heavy rain and severe weather to the Mid-Atlantic Region on October 5.

If a hurricane is a relatively fast-moving storm, it can gain or maintain strength until it makes landfall.  However, it’s quite common for hurricanes to weaken as they make landfall due to a variety of factors such as shallower water, as well as interaction with a given land mass.

Current forecast projections for Hurricane Ian should remind longtime Floridians of Hurricanes Charley, Michael and Opal.  If Ian veers east, then it will move over central Florida like Charley did.  However, if Ian travels further north, then it could make landfall in the Florida Panhandle like Michael and Opal did.