AccuWeather meteorologists are monitoring the potential for changing conditions in the Atlantic basin that may lead to an uptick in tropical activity, including the Caribbean Sea and Gulf of Mexico over the next couple of weeks.
“Indications are that inhibiting factors for tropical development, such as dry air, dust and strong wind shear over the Atlantic basin will start to relax during the week of Aug. 18-25,” according to AccuWeather hurricane expert Dan Kottlowski.
There has been an extensive amount of dry air and wind shear, with flare-ups of Saharan dust in recent weeks. This pattern is anticipated to continue into this weekend.
While this is not unusual during the middle of the summer, we are entering the period of the summer when moist air becomes more plentiful and the amount of dust and wind shear tends to diminish.
Tropical disturbances, or waves, move off the coast of Africa every few days during the summer and into the autumn. This is called the Cabo Verde season, which is named for the group of islands just off the west coast of Africa.
This image taken on Wednesday shows the tropical Atlantic with part of North and Central America to the left and Africa to the far right. The brown color in the middle of the image, over the middle of the Atlantic is dust from the Sahara Desert. The feature of interest for next week is barely recognizable with patchy aimless clouds to the right of the dust area. Image courtesy of NOAA
While waters are sufficiently warm enough to support development in this area from midsummer on, dry air, dust and wind shear keep most of these disturbances from developing into tropical depressions, tropical storms and hurricanes.
“How fast these inhibiting factors relax next week will determine if and when a particular disturbance develops,” Kottlowski said.
“For example, determining the amount of wind shear in a path of a potential tropical system several days out is challenging,” Kottlowski said.
Like other factors in the weather, wind shear can vary significantly from day to day and shift over time as a budding tropical system approaches.
The disturbance, and others will continue to drift westward across the tropical Atlantic in the coming days.
Steering breezes are likely to cause these features to turn more to the northwest and north as they near Central America.
Such a pattern may allow the feature to travel from the northwestern Caribbean, across Mexico’s Yucatan Peninsula, into the western Gulf of Mexico and perhaps toward the western or northern Gulf coast to end next week.
“If the wind shear drops off in the northwestern Caribbean or the Gulf of Mexico, the door may open for development later next week,” Kottlowski said.
Waters are sufficiently warm in the region to support development should the shear ease up.
Interests from Belize and eastern Mexico to the western and northern Gulf coast in the United States, including petroleum operations in the Gulf of Mexico, should monitor the progress of this feature.
In absence of any organized feature, a surge in drenching downpours and locally gusty thunderstorms is possible late next week along the western and/or central Gulf coast.
Elsewhere over the Atlantic, a stalled swath of showers and thunderstorms along the upper Gulf coast and the southern Atlantic coast of the United States has a remote chance of generating a weak tropical disturbance into this weekend.
Since such a feature will be too close to land, development into a significant tropical system is not anticipated. However, even with or without a disturbance the region will be an unsettled focal point for locally heavy rain and the risk of urban flooding.
While the hurricane season extends from June 1 through Nov. 30, the period from the last part of August through October marks the prime time for tropical storms and hurricanes in the Atlantic basin.
The sharpest increase in tropical storm and hurricane frequency occurs from Aug. 20 through Sept. 11.
AccuWeather is predicting a total of 12-14 named storms with five to seven hurricanes and two to four major hurricanes for the 2019 season.
AccuWeather meteorologists estimate an additional one to three named-storm landfalls in the United States for the balance of the season, following Hurricane Barry from the middle of July.