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

August 2,2016
A tropical disturbance, Invest 97-L, now entering the western Caribbean Sea is still trying to develop into a tropical storm, and will likely track toward Belize and Mexico's Yucatan Peninsula late in the week.
A Hurricane Hunter reconnaissance mission will investigate the disturbance, now south-southwest of Jamaica, to see if a sufficiently-defined low-level center, which has been absent, is now in place to categorize this as Tropical Storm Earl.
(MORE: What is an Invest?)
The NHC sent a Hurricane Hunter reconnaissance mission to investigate the system Monday afternoon. However, the aircraft had to turn back early due to maintenance issues.

Invest 97-L Satellite and Position

Despite not being a tropical depression or storm, at least six people were killed in the Dominican Republic Sunday as this system passed near the island.
(MORE: 6 Killed in Dominican Republic as Tropical System Dumps Heavy Rain)
So far Tuesday, the heaviest rain has remained generally just south of Jamaica, though radar from the Meteorological Service of Jamaica showed some rainbands wrapping into the mountainous island early Tuesday.
Satellite scatterometer data has consistently shown winds from 40-45 mph on the northern side of Invest 97-L since early Monday morning. Therefore, it is likely any upgrade to this disturbance may be directly to Tropical Storm Earl.
Regardless of when this occurs, showers and some tropical storm-force winds will spread across Jamaica and the Cayman Islands Tuesday and Tuesday night.
Some local flash flooding can't be ruled out over the mountainous terrain of Jamaica.

Computer Model Track Forecast For Invest 97-L

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 97-L (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 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.

Forecast Rainfall Associated with Earl

By Friday, the system, assuming it survives the voyage over land, may emerge over the Bay of Campeche and restrengthen before a second landfall in eastern Mexico this weekend.
For now, the chance of U.S. impacts appear very low, with the exception of a possible modest push of moisture and showers into parts of the Texas coast.
(FORECAST: S. Padre Island | Corpus Christi)
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