Tropical Storm Earl Forms in the Caribbean; Hurricane Watches Issued

August 2,2016
Tropical Storm Earl has formed in the Caribbean Sea, the first Atlantic basin named storm since late June.
Earl will track toward Belize and Mexico's Yucatan Peninsula, where strong winds and heavy rainfall will be threats late Wednesday into Thursday. Current indications are that the chance of a direct impact on the U.S. from Earl is low.

Projected Path

(MORE: Hurricane Central)
Earl was named late Tuesday morning after a Hurricane Hunter reconnaissance mission found that an area of low pressure had formed.
Tropical storm warnings and hurricane watches have been issued for parts of the Yucatan Peninsula.
This system has already been impactful the last few days prior to being named Earl. Six people were killed in the Dominican Republic Sunday into Monday as this system passed near the island.
(MORE: 6 Killed in Dominican Republic)
Here is what to expect from Earl.

Earl Latest Status and Forecast

The center of Earl was located about 535 miles from Belize City, Belize, as of late Tuesday morning. Earl was moving toward the west at 22 mph.
(MORE: 4 Things to Know About Earl)

Current Status

In the near term, showers and some tropical storm-force winds will impact Jamaica and the Cayman Islands Tuesday and Tuesday night.
Some local flash flooding can't be ruled out over the mountainous terrain of Jamaica.

Forecast Rainfall Associated with Earl

Beyond that, thanks to strong high pressure aloft over the southern United States, it looks most likely that Earl will be steered toward the coast of Belize or Mexico's Yucatan Peninsula late Wednesday or early Thursday, either as a tropical storm or, perhaps, even a low-end hurricane.
(FORECAST: Belize City | Cancun | Cozumel | Grand Cayman)
Bands of locally heavy rain, and, if the center track of "future Earl" is far enough south, strong winds, may be felt in parts of Honduras, as well from Tuesday night into possibly Thursday.
Then, the heavy rain swath tracks through Belize and Guatemala and parts of the Yucatan Peninsula into southern and eastern Mexico. Flash flooding and mudslides in mountainous terrain are threats.
By Friday, the system, assuming it survives the voyage over land, may emerge over the Bay of Campeche and restrengthen before a second landfall most likely in eastern Mexico this weekend.

Any U.S. Impacts?

For now, the chance of U.S. impacts appears very low, with the exception of a possible push of moisture and showers into parts of the Texas coast.
That said, given that this forecast is still several days way, check back for any possible changes.
Rip currents may also impact the Gulf Coast.
(FORECAST: S. Padre Island | Corpus Christi)

August and September: More Favorable For Development

Tropical waves that emerge off the African coast often develop around or even well after passing the Cape Verde Islands. Earl developed from one such tropical wave.
(MORE: When the Atlantic Hurricane Season Ramps Up)
Meteorologists make frequent references to the "Cape Verde" season, which is essentially a season within the overall hurricane season. Most Cape Verde storms develop from mid-August until late September.

Expanding high pressure ridge creates a more favorable environment for tropical systems to develop and move westward in the Alantic

There are so many "mouse traps" (unfavorable conditions) in the Atlantic that very few of these Cape Verde tropical storms and hurricanes ever make it all the way to the United States. But there have been some notable Cape Verde storms that made it to the East Coast of the U.S., such as the 1938 Hurricane, Hurricane Hugo in 1989 and Hurricane Andrew in 1992.
Development of tropical waves into tropical storms or hurricanes is determined by several environmental factors that can range from somewhat favorable to extremely favorable, including:

• Ocean temperatures
• The orientation of ridges (high pressure) and troughs (low pressure) aloft
• A moist environment

In general, the ocean temperature needs to be around 80 degrees for tropical cyclones to develop. Off the coast of Africa, that doesn't usually occur until late July.
Tropical systems like to have winds that are roughly the same speed and direction through a depth of the atmosphere for maximum development. Wind shear - changing winds with height - tends to break up tropical systems that are trying to develop, displacing convection away from a center of circulation.
This often occurs when a trough of low pressure aloft is to the west of a tropical weather system, such that west to southwest winds aloft combine with the typical tropical east-northeast trade winds to produce wind shear.
In August and September, a high-pressure ridge aloft, known as the Bermuda-Azores high, often expands and creates a more favorable environment for development. Atlantic systems are often steered toward the western Atlantic, Caribbean Sea and sometimes all the way to the U.S.
MORE: Retired Atlantic Hurricanes and Tropical Storms