June 1 is the official start to Atlantic hurricane season, but a weather system forming now may make this the sixth straight year with a tropical system forming before that date.
Previous preseason storms
“Gradual development is still expected, and the system is likely to become a tropical or subtropical depression or storm on Saturday while it passes the northwestern Bahamas,” the National Hurricane Center (NHC) said.
There is an 80% chance the system forms into a named storm system by Sunday evening, the NHC says.
Regardless of if it gets a name or not, the storm will bring periods of heavy rainfall to parts of the Florida Keys, southeastern Florida, and the Bahamas, through Saturday.
A flash flood warning was in effect for northern Miami-Dade County in southeastern Florida until 1 a.m. ET. Almost 1.5 inches of rain fell Friday in Miami, the National Weather Service said.
Tropical-storm-force wind gusts are also possible across the system.
“Dangerous surf conditions and rip currents are possible along portions of the southeast US coast this weekend and early next week,” the NHC says.
If and when the named storm forms, most forecast models keep the storm just off the southeastern coast before curving it back out farther into the Atlantic.
Areas of the Pacific Ocean have also had an interesting start to their tropical season. On April 25, Tropical Depression ONE-E formed south of Mexico’s Baja California region, marking the first tropical depression on record in the month of April for the Eastern Pacific Ocean.
This is quite the contrast to the Western Pacific, which just had its eighth latest start to a tropical season since 1950.
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If this system in the Atlantic does get named, it will be Arthur, however, it may classify more as sub-tropical.
“A subtropical storm is a hybrid between a regular area of low pressure, which has a cold core, and pure tropical system which has warm core,” explained CNN meteorologist Dave Hennen.
For a subtropical storm to become a hurricane, it has to become fully tropical by establishing a warm core and then strengthen to hurricane-force winds.
“This potential storm is not likely to become a full hurricane,” CNN meteorologist Chad Myers said. “Still, with ocean temperatures above normal most of the year, the middle of May will likely become the new start of tropical storm season.”
Conditions are becoming favorable for tropical development
While the system is largely unorganized now, it is expected to move into an area of lower wind shear, which is a much more favorable environment. This will allow the storm to become more organized and strengthen.
Sea surface temperatures continue to remain above average across the Atlantic – except for the cooler North Atlantic.
According to the National Hurricane Center, a US Air Force Reserve Hurricane Hunter aircraft is scheduled to investigate this system on Friday to determine how organized the storm is becoming and the strength.
Warm surface temperatures are the fuel needed for hurricane development.
There are over a dozen early forecasts published. And even though the official forecast from the National Oceanic and Atmospheric Administration won’t come until May 21, a strong consensus in the forecasts across the industry indicates the Atlantic is in for an active season.
