Invest 97-L Likely to Become Tropical Storm Earl, Pose Threat to Belize, Mexico's Yucatan Peninsula

August 1,2016
A tropical disturbance moving through the eastern Caribbean Sea is now likely to develop into a tropical storm and track toward Belize and Mexico's Yucatan Peninsula late in the week.
The National Hurricane Center (NHC) said that the system, Invest 97-L, has a high (80 percent) chance of developing during the next two days.
(MORE: What is an Invest?)

Invest 97-L Satellite and Position

On Monday morning, convection had pulsed up significantly south of the Dominican Republic, with infrared imagery taking on the "sunny-side-up egg" look consistent with more consolidated convection.
However, there was not yet a surface center of circulation verified, which is a criterion for classification as a tropical cyclone. An early-morning scatterometer pass was just a bit too far east to see any possible west wind associated with Invest 97-L. Since trade winds in the Caribbean blow generally from east to west, a west-to-east wind would confirm the closed circulation.
The NHC said a Hurricane Hunter reconnaissance mission will investigate the system later Monday afternoon to determine whether Invest 97-L has become a tropical depression or storm.

The aforementioned scatterometer pass early Monday morning found winds over 40 mph on the northern and eastern flank of Invest 97-L. Therefore, it is looking increasingly possible any upgrade to this disturbance may be directly to Tropical Storm Earl.

Regardless of when this occurs, showers and some gusty winds will spread across Hispañola Monday, then across eastern Cuba, Jamaica and the Cayman Islands Monday night into Tuesday.
Locally heavy rain may trigger flash flooding over the mountainous terrain of Hispañola, Jamaica and eastern Cuba.

Forecast Rainfall Associated with 97L

Beyond that, thanks to strong high pressure aloft over the southern United States, it looks most likely "it" 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.
Interests in those areas should monitor closely the progress of Invest 97L (future "Earl").
(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 late Tuesday into possibly Thursday.
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.
For now, the chance of U.S. impacts appear very low, with the exception of a possible push of moisture and showers into parts of the Texas coast.
(FORECAST: S. Padre Island | Corpus Christi)

Computer Model Track Forecast For Invest 97-L

Technically, the Atlantic hurricane season runs from June 1 through Nov. 30. Much of the tropical activity occurs between the second week of August and the second week of October. In late July and early August, we begin to keep an eye on the eastern Atlantic as it begins to show signs of life.
(MORE: When the Atlantic Hurricane Season Ramps Up)

August and September: More Favorable For Development

Tropical waves that emerge off the African coast often develop around or after passing the Cape Verde Islands.
(MORE: Why Tropical Waves Are Important)
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.
Since the area from Africa to the eastern Atlantic looks quite active already and we now have a tropical system of interest, it'll be interesting to see what the rest of the hurricane season will have in store.
MORE: Retired Atlantic Hurricanes and Tropical Storms