Weather Alert: Caribbean Braces for Tropical Storm Bret and Impending Downpours

As the eastern Caribbean prepares for an unusually early storm, Tropical Storm Bret is steadily advancing towards the region, carrying the potential for heavy downpours.

Late on Tuesday night, the National Hurricane Center in Miami provided an update, stating that Bret currently has maximum winds of 50 mph (85 kph) and is moving westward across the Atlantic Ocean at a speed of 17 mph (28 kph). However, accurately assessing the storm’s intensity and size remains challenging, as acknowledged by the center.

Bret is presently located approximately 730 miles (1,170 kilometers) east of the Windward Islands and is expected to impact several eastern Caribbean islands on Thursday, potentially intensifying to near hurricane strength. As a result, a tropical storm watch has been issued for Barbados, St. Lucia, Martinique, and Dominica. Dominica’s meteorological service classifies the storm as a “high threat,” cautioning about the potential for landslides, flooding, and waves up to 12 feet (4 meters) in height.

Fitzroy Pascal, from Dominica’s Office of Disaster Management, voiced concerns over landslides due to compromised ground conditions resulting from a relatively dry period.

Simultaneously, the National Hurricane Center urges individuals in the Lesser Antilles, Puerto Rico, and the Virgin Islands to closely monitor the storm’s progression and ensure their hurricane preparedness plans are in place. Given the uncertainties surrounding the storm’s track and intensity, the center emphasizes that it is premature to pinpoint the specific locations and magnitude of potential hazards associated with Bret.

Rainfall estimates indicate that the French Caribbean island of Guadeloupe, extending south to St. Lucia, may experience accumulations of up to 10 inches (25 centimeters), while Barbados and St. Vincent and the Grenadines could receive up to 4 inches (10 centimeters) of rainfall.

The government of Guadeloupe has issued a warning, alerting residents to inclement weather starting Wednesday evening and lasting through late Friday, accompanied by the possibility of 10-foot (3-meter) waves.

Unfavorable winds and drier air are expected to weaken Bret as it moves through the central Caribbean region. Some models even suggest that the storm might dissipate after impacting the eastern Caribbean islands.

Tropical Storm Bret formed on Monday, marking an early and active start to the Atlantic hurricane season, which officially began on June 1. Following closely behind Bret is a tropical disturbance with an 80% chance of cyclone formation. Meteorologist Philip Klotzbach from Colorado State University highlights that no previous June on record has witnessed the formation of two storms in the tropical Atlantic.

The National Oceanic and Atmospheric Administration projects that this year’s hurricane season will feature 12 to 17 named storms. Among them, five to nine storms could intensify into hurricanes, with up to four potentially reaching major hurricane status (Category 3 or higher).

Virginia Tech meteorologist Stephanie Zick anticipates a higher-than-average number of storms rapidly intensifying this season due to warmer sea surface temperatures. Zick also emphasizes that flooding caused by tropical systems upon landfall has been responsible for the highest number of fatalities in the past decade.

“Remember, the hazards associated with tropical storms can occur hundreds of miles away from the storm center,” she cautions.

Why Is the Caribbean Climate So Diverse?

From Sun-soaked Shores to Hurricane Seasons

Let’s explore the Caribbean climate and its unique characteristics. The region enjoys the warm embrace of the sun throughout the year. Get ready to discover the distinct wet seasons that often coincide with the Atlantic hurricane season, which runs from June 1st to November 30th each year in the islands and Belize.

Now, let’s delve into the technical aspects of the Caribbean climate. We’ll provide detailed maps showcasing average monthly rainfall and temperatures. These measurements have been diligently recorded by weather stations spread across the region. Additionally, you’ll find comprehensive statistics on rainfall and temperatures for each territory and specific weather station, offering a deeper understanding of the local climate.

Key Characteristics of the Caribbean Climate

The Caribbean experiences consistently pleasant temperatures year-round, enveloping the region in perpetual warmth. The annual temperature range varies, from less than 2°C in extreme southern areas to approximately 5°C in the high elevations of the far north.

Each year, the Caribbean witnesses a distinct dry season and wet season, except in the Guianas. The wet season occurs from May/June to November/December, while the dry season covers the other half of the year. It’s fascinating how the wet season and the hurricane season often align due to similar factors.

During the wet season, heat stress intensifies, particularly during dry spells when rain and cloud cover are scarce. Humidity and heat become more prominent, creating challenging conditions. On the other hand, the breezy and cooler dry season provides a welcome respite from humidity, offering a refreshing atmosphere.

Physical and Dynamic Drivers of Caribbean Climate Seasonality

(For weather and climate professionals, as well as enthusiasts)

The wet and hurricane seasons in the Caribbean are influenced by various factors:

1. The migration of the Hadley Cell and the Inter-tropical Convergence Zone (ITCZ) from 2-5°N in March to 12-15°N in September plays a crucial role in shaping the seasons.

2. This migration leads to changes in the strength and northward movement of the sub-tropical (Bermuda-Azores) High-Pressure system, further impacting the climate.

3. Sea surface temperatures (SST) generally range between 27-30°C, creating favorable conditions for the development of tropical cyclones, including hurricanes.

4. Migrating tropical waves and disturbances have the potential to strengthen and evolve into significant weather systems, contributing to the intensity of the seasons.

The peak of the wet and hurricane seasons typically occurs around September/October when SSTs are highest and the ITCZ reaches its northernmost position.

In the Guianas, the migrating ITCZ is the primary reason for the observed double rainfall peaks between May-July and November-January.

The dry season is triggered by the southward migration of the Hadley Cell, the subtropical high-pressure system, and the ITCZ. As these systems move, they bring about a more stable atmosphere. The heart of the dry season falls between February and April. In the northern regions, most of the dry season’s rainfall is associated with the passage or stalling of cold fronts, with the remnants of these fronts providing rainfall to the eastern Caribbean.