Atlantic Disturbance Moving into the Caribbean but Remains Disorganized

Forecast models waffle on development deeper into the Caribbean, maintaining a weak system this week

Monday morning tropical Atlantic satellite. Credit: NOAA

Despite several disturbances peppering the Atlantic from the Gulf of Mexico to Africa this Labor Day – a traditionally active turn in the hurricane season – none show any immediate signs of development.

The streak of underperformance across the Atlantic since Hurricane Ernesto raced out to sea two weeks ago tomorrow has been nothing short of surprising, and we’ve discussed the myriad factors potentially at play in previous newsletters. The conundrum continues this week as the enthusiasm of forecast models wanes while they once again struggle to find the next named storm candidate. The change of tune could extend the mid-season rain delay through the first full week of September, a welcome development amidst what virtually all seasonal forecasts called to be an extremely active hurricane season.

Storminess struggling to organize as disturbance enters the Caribbean

The main event in the Atlantic this week is a disturbance now blowing through the easternmost Caribbean islands. This weekend the tropical wave struggled to produce much in the way of consolidated storminess as it moved westward through the central Atlantic. This has been a common theme with disturbances in the tropical Atlantic so far this season as intrusions of dry and stable air dampen development odds.

Today it will continue to battle wind shear-related impediments and should stay disorganized as it brings rounds of blustery showers to the Lesser Antilles, Puerto Rico, and the U.S. Virgin Islands through Tuesday.

As we discussed on Friday, the system is expected to move westward and deeper into the Caribbean where conditions appear more conducive for development. That said, models have significantly pared back the number of scenarios showing development over the western Caribbean from just a few days ago.

European model ensemble forecast tracks through Saturday, September 7^th from last Friday (top panel) compared to the latest overnight run today (bottom panel). Just a few days ago, most scenarios indicated development deeper in the western Caribbean, including some strong scenarios. Today, few scenarios show development and those that do maintain a weak system into the upcoming weekend. Credit: Weathermodels.com

Although forecast models are now tepid on development, the National Hurricane Center is maintaining a medium chance of development later this week as the disturbance reaches the central and western Caribbean, where upper-level winds will be light and water temperatures are historically warm.

Low pressure tracks through Saturday morning (September 8^th) from the European model ensemble system. Most ensemble scenarios keep the system weak before moving it inland into parts of Central America this weekend. Credit: Weathernerds.org

The good news for us in South Florida is that regardless of development, high pressure steering to the north should keep the system or what forms from it on a trajectory well south and west of us into next weekend. The most likely scenario keeps the system moving into Central America this weekend and perhaps emerging over the southern Gulf of Mexico by early next week.

For now we’ll monitor its progress for our Latin American neighbors, but we don’t have any concerns for Florida in the week ahead.

Gulf disturbance meanders, with lingering heavy rain threat to coastal Texas

A broad area of low pressure festering along the upper Texas coast will make for an ugly Labor Day along most of the state’s Gulf Coast beaches.

Enhanced satellite through around 9 AM Monday showing disorganized storminess in the western Gulf of Mexico around a broad area of low pressure along the upper Texas coast. Credit: TropicalTidbits.com

The disturbance, which has been meandering just offshore for several days could bring scattered flash flooding, including pockets of street flooding and flooding of low-lying areas, from the Houston/Galveston area southward to Matagorda Bay and Corpus Christi.

Day 1 Excessive Rainfall Outlook from the National Weather Service showing a slight chance of excessive rainfall for the Texas Gulf Coast for Labor Day which could lead to scattered flash flooding, especially in low-lying areas. Credit: Pivotal Weather

It’s unlikely it will develop before moving inland tomorrow, but regardless heavy rain and flash flooding remain the greatest threats through mid-week.

Possible development in the far eastern Atlantic

Forecast models are advertising a modest shot of development this week for a slow-moving tropical wave off the coast of Africa. Though the system could bring some weather to the Cabo Verde Islands over the next few days, it’s expected to stay far out to sea for the remainder of this week.