Tropical Storm Josephine to veer away from U.S. mainland

Aug. 14 --

Tropical Storm Josephine is expected to keep well north of Puerto Rico and east of the mainland United States to avoid serious impacts there, forecasters said Saturday.

As of 5 p.m. Saturday, Tropical Storm Josephine was moving to the west-northwest near 17 mph and was located about 160 miles to the east-northeast of the northern Leeward Islands. The system's maximum sustained winds were 45 mph.

Josephine has shattered the early-season formation record for the J-named storm in the basin by nine days. The former record belonged to Jose, which developed on Aug. 22, 2005.

Prior to Josephine, the 2020 hurricane season as already left its mark on the history books multiple times so far with storms Cristobal, Edouard, Fay, Gonzalo, Hanna and Isaias all setting early-season formation records. Except for Cristobal, the storms bumped off record-setters from the 2005 season. The prior earliest C-named storm was Colin from 2016.

A disturbance spinning over the middle of the Atlantic organized enough to be named Tropical Depression 11 at 5 p.m. EDT Tuesday, according to the National Hurricane Center. At 11 a.m. Thursday, the depression was upgraded to the ninth tropical storm of the 2020 Atlantic hurricane season and in the process has set another record for the basin.

U.S. Air Force Reserve Hurricane Hunter aircraft is scheduled to investigate Josephine later Friday, according to the National Hurricane Center.

Josephine was able to form despite being in a sea of dry air as wind shear dipped enough to allow thunderstorms to wrap around the center of the storm.

"The tropical cyclone probably has through Friday night to strengthen before encountering increasing vertical wind shear from the southwest," AccuWeather's top hurricane expert, Dan Kottlowski, said.

"After that, Josephine is forecast to move into increasing vertical wind shear, which would likely cause it to lose wind intensity," he added.

"We expect Josephine to move on a curved path to the northwest then the north in the coming days," Kottlowski stated.

Josephine will move along the western part of the Bermuda-Azores high pressure area, which is a fairly permanent feature of clockwise steering winds over the middle of the Atlantic Ocean.

"On this forecast track, the evolving tropical storm will pass just northeast of the Leeward Islands this weekend and pass well northeast of the Bahamas early next week," Kottlowski stated.

The Leeward Islands include Antiqua, Guadeloupe, Barbuda, Montserrat, Dominica, St. Martin, Anguilla, St. Kitts and Nevis, and the British and United States Virgin Islands.

Since Josephine is likely to remain poorly organized or at least no better than a moderate tropical storm through this weekend, impact on the Leeward Islands to Puerto Rico will likely be limited to a couple of showers and perhaps a gusty thunderstorm. Rainfall of 1 inch to perhaps as much as 3 inches may fall on some of the islands.

"Conditions on these islands should be no worse than that of a moderate tropical wave moving through," Kottlowski said.

"The weakening system is forecast to approach Bermuda during Wednesday of next week. By that time, Josephine could be a depression, but it still might have a large area of rain and gusty winds that could impact Bermuda," Kottlowski said.

However, Josephine is not forecast to have direct impact on the mainland United States, thanks to a southward dip in the jet stream that will keep the storm at sea.

Strong wind shear is a deterrent for tropical systems as these strong breezes at different levels in the atmosphere can rip apart organized systems or prevent tropical features from developing altogether.

There is a zone of moderate wind shear hovering over the Caribbean and in areas to the north of the northern islands of the Caribbean.

"There is a good chance that this feature, regardless of its organization and strength into Friday night, would begin to unravel in the zone of wind shear and drier air this weekend," Kottlowski said.

There is also a chance that dry air, nearby to the north of the feature, continues to be ingested, and the system never really gains enough steam to strengthen much beyond moderate tropical storm strength.

Additional disturbances, known as tropical waves, will continue to move from the Indian Ocean, across Africa then over the Equatorial Atlantic Ocean in the coming days, weeks and months.

This train of disturbances makes up what is known as the Cabo Verde season, which is named for the group of islands just off the northwestern coast of Africa. The Cabo Verde season makes up the backbone of the Atlantic hurricane season during the period from late August to the first part of October.

Into part of next week, there will be a continued risk for one or more of these systems to organize and potentially evolve into a tropical depression or storm. But for the time being, the buffer of wind shear over the Caribbean and across part of the southwestern Atlantic may act as a shield and prevent systems from getting too close to United States waters and coastal areas.

However, that buffer zone may not last long and this does not rule out the potential for something forming north of the wind shear zone, perhaps right along the East Coast of the United States in the short term.

"We will be closely watching an area of disturbed weather that emerges from the showers and thunderstorms in the Southeastern states into this weekend," Kottlowski said.

There is a high chance this disturbance could evolve into a tropical depression or storm well to the east of the mid-Atlantic coast and south of the New England coast into this weekend as it moves northeastward. The next name on the list of tropical storms for this season is Kyle.

The lid could come off the Atlantic basin with the potential for multiple named systems spinning at the same time, including multiple threats to lives and property at the same time from the Caribbean to North America, as early as late August.

Tropical storms are named for most letters of the alphabet, with the exception of Q, U, X, Y and Z. The infamous 2005 Atlantic hurricane season holds the record for the greatest number of named storms at 28 and still holds the record for early-season formation records for the "K-storm," which was Katrina on Aug. 24, as well as the letters M through T, V and W. After W, Greek letters are used. Since 2005 was the only year to use Greek letters, that season holds the early-season formation records beyond W.

AccuWeather meteorologists are expecting a hyperactive year for tropical storms and hurricanes--enough that Greek letters may once again be needed. Due to 2020's record pace and upcoming conditions expected in the basin, in early August, AccuWeather meteorologists upped their forecast for the number of tropical storms, with up to 24 now predicted and up to 11 hurricanes projected for the season.

The climatological peak for the Atlantic hurricane season is around Sept. 10.

Meanwhile, in the East Pacific Ocean, Elida strengthened into a hurricane earlier this week. The storm stayed at sea and became post-tropical on Wednesday evening. However, already a new depression has formed and could be followed by several other named systems in the next five to seven days.

Kottlowski is expecting the eastern Pacific to "go wild with tropical activity over the next several weeks" and the Atlantic may follow suit toward the end of August and into the autumn months.