Preliminary Report
Tropical Storm Bret
04 - 11 August 1993

1993 PRELIMINARY REPORTS

Tropical Storm Arlene (TS)
Tropical Storm Bret (TS)
Tropical Storm Cindy (TS)
Tropical Storm Dennis (TS)
Hurricane Emily (3)
Hurricane Floyd (1)
Hurricane Gert (2)
Hurricane Harvey (1)

Bret moved on a due westward course for much of its existance, remaining at an unusually low latitude. Flooding and mud slides from Bret's rains caused many deaths in Venezuela.

 

a. Synoptic History

A tropical wave which moved off the west coast of Africa on 1 August was the system that spawned Bret. This wave was among several, during late July and early August of 1993, that looked impressive in terms of amount and organization of deep convection. Only a day later, the convection associated with the wave became well organized enough for the National Environmental Satellite and Data Information Service (NESDIS) Synoptic Analysis Branch (SAB) to classify the system as a T1.0 on the Dvorak scale. By 1200 UTC on 4 August, the thunderstorm activity became more concentrated, and the development of curved convective bands were noted. Both the SAB and the Tropical Satellite Analysis and Forcast (TSAF) Unit of the National Hurricane Center (NHC) were classifying the system as a T2.0 at that time. Therefore, a tropical depression is estimated to have formed from this system, about 1000 nautical miles to the west-southwest of the Cape Verde Islands, on 4 August near 1200 UTC.

The cyclone moved on a westward course at an increasing forward speed during the ensuing 12 to 24 hours. Around 0000 UTC on 5 August, satellite estimates indicate that the system strengthened to become Tropical Storm Bret. By 1200 UTC on the 5th, Bret was moving westward near 23 mph. A steady westward motion at 18 to 24 mph was maintained for the next 4 days or so, due to a strong deep-layer ridge that remained established to the north of the storm throughout most of its lifetime.

The storm initially appeared to have adequate upper level outflow and Bret's mximum winds increased to around 58 mph by 0600 UTC on the 6th. However, by 1800 UTC on the 6th, the center of the storm became exposed near the north-northwestern edge of the main convective cloud mass. The dense overcast became re-established over the center of the storm a few hours later, as Bret neared the island of Trinidad and the northern coast of Venezuela. Based on Air Force Reserve Unit reconnaissance aircraft observations, the central pressure fell to 1002 mb just after 1800 UTC on the 6th. The storm moved across the northern part of Trinidad early (around 0800 UTC) on the 7th, and the center moved along a portion of the northern coast of Venezuela a few hours later. Around 2000 UTC on the 7th, the center was back out over the water, just offshore of the coast, and by 0800 on the 8th, Bret moved over the extreme northwestern part of Venezuela. The center continued westward over the extreme northern sections of Colombia on the 9th.

After interacting with some mountainous terrain over Venezuela, Bret encountered a tremendously high mountain over Colombia, Pico Cristobal Colon, whose peak is about 19000 feet above sea level. The circulation was weakened considerably by this mountain and Bret was reduced to a tropical depression as it emerged over the waters of the southwest Caribbean Sea around 0900 UTC on the 9th. Indeed, Bret was so severely disrupted by the mountains that the circulation had practically dissipated. However, later during the day on the 9th, convection increased in bands over the southwest Caribbean. The upper-troposperic flow over the area was mostly straight southwesterly at the time Bret moved off the coast of Colombia, but later on the 9th the upper-level flow became increasingly anticyclonic. Bret regenereated into a tropical storm by 0600 UTC 10 August, while located about 140 nautical miles to the east of the southern coast of Nicaragua. The forward motion slowed to 12 to 16 mph as the storm neared southern Nicaragua. Based on satellite intensity estimates, Bret's maximum winds were near 46 mph when the center crossed the coast of southern Nicaragua near Bahia Punta Gorda around 1700 UTC 10 August.

After moving inland, Bret turned toward the west-northwest. It is considered to have dissipated as a tropical cyclone when it neared the Pacific coast of Nicaragua around 1800 UTC 11 August, since a low-level circulation could no longer be clearly indentified at that point. Nonetheless, a remnant disturbance could be tracked westward and west-northwestward over the eastern pacific for a few days. The system eventually regenerated into east Pacific Tropical Depression Eight-E, which later became Hurricane Greg.

b. Meteorological Statistics

The island of Margarita reported wind gusts to 53 mph. The weather station of Grenada reported maximum sustained winds of 37 mph with gusts to 45 mph. A sailing yacht, the Lady Elaine, anchored at Hog Island on the south coast of Grenada, measured a sustained wind of 46 mph. Guiara, Venezuela (near the first landfall point in South America) reported a wind gust to 44 mph. The highest gust reported from Curacao was 40 mph.

1. Rainfall Data

During the passage of Bret over Venezuela on 7-8 August, 13.35 inches of rain reportedly fell in a 10 hour period at Guanare (state of Portuguesa). Another 24-hour rainfall amount of 11.23 inches was reported from Quebarada Seca (state of Barinas). Among various reporting sites in Caracas, a maximum 24-hour total of 5.98 inches is indicated, with up to 4.72 inches occurring during a 7-hour period.

c. Casualty and Damage Statistics

There were 184 deaths attributed to Bret; 173 in Venezuela, 10 in Nicaragua and 1 in Colombia

Flooding and mud slides, due to heavy rainfall associated with Bret, caused a major catastrophe in Venezuela. The government of Venezuela reported a total of 173 deaths and "many" missing. The majority of the deaths occurred in the low income areas surrounding Caracas, where many people reside in ramshackle huts. Press reports indicated at least 10,000 were homeless in Venezuela and Bret caused an estimated $25 Million worth of damage in that country. There was 1 death and 1 injury reported from Colombia. In Nicaragua, a total of 10 deaths were reported. Nine of these fatalities occurred offshore near Isla de Maiz, when (according to ham radio reports) a spanish vessel sank. There were also reportedly 35,000 persons "displaced" in Nicaragua due to Bret.