A Slight Uptick
Percent of named storms by month since 1950.
From 1950-2012, 56 named storms have formed in July, for an average each year of one July named storm. Incidentally, the season’s first named storm will have formed by the second week of July in a typical season.
Of those named storms from 1950-2012, 26 strengthened to hurricanes, for an average of one July hurricane every two to three years.
Major hurricanes (Category 3 or stronger on the Saffir-Simpson Hurricane Wind Scale) in July are quite rare. Only five major hurricanes have flared during the hurricane season’s second month since 1950.
Where do July’s named storms typically form and track?
A Subtle Shift East
The month of July is a month of transition. Formation areas spread east to include the Atlantic Ocean to the east of the Lesser Antilles.
“The tropical waves coming off of western Africa every 2-4 days are a little better defined than in June,” says Dr. Rick Knabb, Director of the National Hurricane Center and former Hurricane Expert at The Weather Channel. “That’s one reason why we start to look farther east for development in July.”
(MORE: Where Hurricanes Come From)
That said, the primary season for long-track tropical cyclones from the eastern Atlantic, known as “Cape Verde” storms, is in August and September.
The Gulf of Mexico, meanwhile, remains somewhat active in July, though the western Caribbean Sea steps down a bit.
“Cold fronts, one of the ‘seeds’ of a tropical cyclone, are much less likely to reach the tropics in July vs. June. At the same time, water temperatures have not yet reached their peak.”
Development can also occur from north of Puerto Rico to the Bahamas and Bermuda. While the “typical track” would take most of these tropical cyclones away from the U.S. East Coast, remember that’s just an “average.” At times, these storms can linger off the East Coast, churning up high surf leading to beach erosion and rip currents.
These are all averages. Not every July follows this perfect script. Let’s examine some recent notable July examples.
Recent July Notable Storms
In July 2010, Hurricane Alex made landfall as the calendar turned to July in northern Mexico, wringing out torrential, flooding rain in the Rio Grande Valley and Monterrey, Mexico. In 2011, we had three named storms form in the Atlantic basin during July.
The transition to formation areas in the central and eastern Atlantic mentioned earlier was illustrated in one of the most extreme examples in 2008.
Only July 3, 2008, Tropical Storm Bertha became the farthest east named storm to form in the Atlantic Basin so early in the season in the satellite era. Bertha’s formation point is represented by the dot at the right edge of the graphic at the lower left, south of the Cape Verde Islands. Bertha went on to become the earliest-in-season hurricane farthest east in the Atlantic (at about 50W longitude) and went on to become the longest-lived July named storm on record, lasting 17 days in the open waters of the Atlantic Ocean.
Named storm origin points in early July.
Also in July 2008, Category 2 Hurricane Dolly made landfall in southern Texas.
The record-smashing 2005 hurricane season was very active in July.
Following landfall of Hurricane Cindy in southeast Louisiana, Hurricane Dennis, was, at the time, the strongest July Atlantic Basin hurricane on record, before landfalling in the Florida Panhandle.
Incredibly, just six days after Dennis made landfall, Hurricane Emily, became the only Category 5 July hurricane of record in the Atlantic Basin, churning in the Caribbean Sea before striking Cancun and Cozumel, Mexico. Five named storms formed in July 2005.
On the other hand, there have been plenty of Julys with nary a named storm. Three straight Julys (1999-2001) were devoid of even a single named storm. July 2012 was also inactive with zero named storms.
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