Hurricane seasons often start quietly

 

Tropical Storm Debby, June 2012 (Source: NOAA)

Hurricane season in the Atlantic Ocean Basin runs from June 1 through November 30. The quietest months of the season are typically June and November when atmospheric and environmental conditions are the least favorable for development. That’s not to say there haven’t been a few high impact tropical storms and hurricanes during the month of June. The Atlantic Ocean Basin includes the Gulf of Mexico and Caribbean Sea, areas more favorable for development early and late in the hurricane season.  

Debby (2012):  Tropical Storm Debby is an example of how a tropical system doesn’t have to be intense to have significant impacts. That’s because both tropical storms and minimal hurricanes have the potential to bring significant amounts of rain, along with coastal flooding and beach erosion. Such was the case with Debby across much of central and northern Florida, where isolated rainfall totals of more than 20” were observed. The heavy rain attributed to Debby and its remnants helped make June 2012 the wettest on record in Tampa.

Allison (2001):  While it was only a tropical storm at peak intensity and when it made landfall in Texas, Allison achieved a dubious honor. It was the first of only two Atlantic tropical storms to have had its name retired by the World Meteorological Organization. Tropical storm and hurricane names are retired for being damaging and/or deadly (e.g., Katrina, Andrew or Michael). What made Allison unique wasn’t its intensity, but its longevity. After making landfall in Texas, its remnants lingered for days and caused devastating flooding. Not until Hurricane Harvey in August 2017 did Texas residents see comparable flooding.

Agnes (1972):  Agnes became a minimal hurricane over the eastern Gulf of Mexico on June 18, but isn’t remembered for that. Agnes menaced much of the Mid-Atlantic and northeastern United States where its remnants caused widespread flooding. Multiple June rainfall records were set from Virginia to New York, including DC’s wettest June day overall (6.11” on June 21, 1972). Agnes subsequently had its name retired.

Alma (1966):  This was the last major Category 3 hurricane that developed in the Atlantic Basin during the month of June. At peak intensity, Alma had sustained winds of 125 mph when it passed over the Florida Keys. It weakened, however, as it tracked north and ultimately made landfall as a Category 1 hurricane in the Florida panhandle. Had a similar storm occurred now, the impacts would be much more significant since Florida’s population and coastal development have increased dramatically in the decades since Alma.

Hurricane intensity is ranked on the Saffir-Simpson Hurricane Wind Scale, with a Category 1 being a “minimal” hurricane with sustained winds speeds of 74 to 95 mph. A hurricane becomes “major” when sustained winds reach 111/+ mph, making it a Category 3. The strongest hurricanes are Category 5’s, with sustained winds of at least 157 mph.