Hurricane Season: What to Expect in July
Linda Lam and Jon Erdman
Published: July 1, 2015
Combined, June and July account for only 14 percent of the Atlantic hurricane season's named storms, paling in comparison to the volume of named storms in the core months of August through October.
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Tropical storm (red) and hurricane (white) frequency by month in the Atlantic Basin.
From 1950-2014, 62 named storms formed in July, averaging out to about one named storm in July each year. 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 1950-2014, 27 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.
A Subtle Shift East
Typical origin and tracks of July tropical cyclones in the Atlantic Basin.
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."
That said, the primary season for long-track tropical cyclones from the eastern Atlantic, known as "Cape Verde" storms, is in August and September.
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The Gulf of Mexico remains somewhat active in July, though the western Caribbean Sea steps down a bit.
Bryan Norcross (On Twitter | On Facebook), hurricane specialist at The Weather Channel, says two factors limit the number of July Atlantic tropical cyclones.
"Cold fronts, one of the 'seeds' of a tropical cyclone, are much less likely to reach the tropics in July versus June. At the same time, water temperatures have not yet reached their peak."
Development can also occur from north of Hispanola to north of the Bahamas. Those storms can either linger off the East Coast, churning up high surf leading to beach erosion and rip currents, curl or recurve harmlessly out into the open Atlantic, or in more rare cases, landfall along parts of the East Coast.
Including 2014's Hurricane Arthur, only five July hurricanes have made landfall along the East Coast since 1950, none reaching Category 3 strength.
These are all averages. Not every July follows this perfect script.
Recent July Notable Storms
Named storm origin points in July.
Over the Fourth of July holiday in 2014, Hurricane Arthur raked eastern North Carolina and the Outer Banks with storm surge flooding and strong winds.
Hurricane Alex made landfall in July 2010 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.
On 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 right, 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.
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 the 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 without a named storm. Three consecutive Julys (1999-2001) were devoid of even a single named storm. July 2012 was also inactive with zero named storms.
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