Potential Tropical Cyclone Twenty-Six Forms In Central Caribbean

The National Hurricane Center has begun issuing advisories on Potential Tropical Cyclone Twenty-Six in the Central Caribbean. Tropical storm watches and warnings are in effect for parts of the Western Caribbean, as well as hurricane watches.

Potential Tropical Cyclone Twenty-Six is forecast to become a tropical storm over the next few days and a hurricane in the Gulf of Mexico later this week.

Given that this system is forecast to become a tropical storm within 48 hours, this will become 26th tropical cyclone of the 2020 Atlantic Hurricane Season and the earliest 25th named storm in Atlantic history. The previous record for the 25th named storm was Gamma, on November 15th, 2005. The last (and only) time Delta was used in the Atlantic was on November 22nd, 2005.

This tropical cyclone is not forecast to impact Trinidad, Tobago, or the Lesser Antilles.

List of names for the 2020 Atlantic Hurricane Season. The next named tropical cyclone will be called Delta.

At 5:00 PM AST, the center of the disturbance was centered near latitude 16.7 North, longitude 76.6 West. The system is moving toward the west-northwest near 10 mph (17 km/h). A west-northwestward to northwestward motion at a slightly faster forward speed is expected over the next few days.

On the forecast track, the center of the disturbance is expected to pass near or just southwest of Jamaica tonight and early Monday, move near or over the Cayman Islands Monday night, and approach the Isle of Youth and western Cuba Tuesday afternoon or evening. The system is forecast to move into the southeastern Gulf of Mexico Tuesday night or early Wednesday.

Maximum sustained winds are near 35 mph (55 km/h) with higher gusts. Strengthening is expected during the next 2 to 3 days and the system is forecast to be a tropical storm when it nears the Cayman Islands, and a hurricane when it moves near or over western Cuba.

Conditions are conducive for development and the system is forecast to become a tropical depression or storm tonight or early Monday, with high chances of tropical cyclone formation over the next 48 hours and 5 days respectively.

The estimated minimum central pressure is 1007 millibars.

Potential Tropical Cyclone Twenty-Six Forecast Track as of 5:00 PM AST Sunday 4th October 2020. (National Hurricane Center)

Watches & Warnings

Potential Tropical Cyclone Twenty-Six Watches and Warnings as of 5:00 PM Sunday 4th October 2020. (National Hurricane Center)

A Hurricane Watch is in effect for:

  • Cuban provinces of Pinar del Rio and Artemisa
  • Isle of Youth

A Tropical Storm Warning is in effect for:

  • Cayman Islands including Little Cayman and Cayman Brac

A Tropical Storm Watch is in effect for:

  • Cuba province of La Habana

A Hurricane Watch means that hurricane conditions are possible within the watch area. A watch is typically issued 48 hours before the anticipated first occurrence of tropical-storm-force winds, conditions that make outside preparations difficult or dangerous.

A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area within 36 hours.

A Tropical Storm Watch means that tropical storm conditions are possible within the watch area, generally within 48 hours.

For storm information specific to your area, please monitor products issued by your national meteorological service.

Hazards Affecting Land

Potential Tropical Cyclone Twenty-Six probabilities for tropical-storm-force winds as of 5:00 PM AST Sunday 4th October 2020, as well as the most likely time of arrival of tropical-storm-force winds. (National Hurricane Center)

STORM SURGE: A dangerous storm surge will raise water levels by as much as 3 to 5 feet above normal tide levels along the immediate coast of the Isle of Youth and along the south coast of western Cuba near and to right of where the center makes landfall. Near the coast, the surge will be accompanied by large and dangerous waves.

RAINFALL: Through midweek, this system has the potential to produce 3 to 5 inches of rain with isolated maximum totals of 8 inches across Jamaica, southern Haiti, and western Cuba. This rainfall could lead to life-threatening flash floods and mudslides. Over the Cayman Islands, 2 to 4 inches of rainfall will be possible with this system.

WIND: Tropical storm conditions are expected in the Cayman Islands beginning late Monday. Hurricane conditions are possible within the Hurricane Watch area by Tuesday afternoon, with tropical storm conditions possible by early Tuesday. Tropical Storm conditions are possible in the Tropical Storm Watch area in Cuba by early Tuesday.

This system is of no direct threat to the Windward Islands, including Trinidad and Tobago.

Potential Tropical Cyclone Twenty-Six Forecast Discussion

Potential Tropical Cyclone Twenty-Six (Weathernerds.org)

Visible satellite imagery and earlier scatterometer data indicated that the circulation associated with the area of low pressure in the central Caribbean Sea has gradually become better defined. The associated deep convection does not yet have enough organization to classify the system as a tropical depression, but there has been some increase in convection just south of the estimated center. The earlier ASCAT data revealed peak winds of around 30 kt over the northeastern portion of the circulation, and that is the basis for the initial intensity. The disturbance is located over warm waters and in a moist environment, but there is some modest northeasterly shear over the system. The global models indicate that the shear will decrease overnight, and the oceanic and atmospheric environment is expected to quite favorable for both the development of a tropical cyclone and subsequent strengthening of the system over the northwestern Caribbean Sea during the next couple of days.

The intensity guidance is quite aggressive, but also assumes that the system already has a tropical cyclone structure. Therefore, the NHC intensity forecast is a little below the intensity consensus during the first 24-48 hours, but does show the system at or near hurricane strength by the time is near western Cuba on Tuesday. Environmental conditions are expected to remain favorable for strengthening over the southeastern Gulf of Mexico, and additional strengthening is predicted during that time. Late in the period, conditions are forecast to become less conducive as the vertical wind shear increases and the system nears the cooler shelf waters of the northern Gulf of Mexico.

The disturbance is moving west-northwestward or 290/9 kt. A mid-to upper-level ridge over the western Atlantic is forecast to build westward over the next few days, which should continue to steer the system west-northwestward to northwestward over the northwestern Caribbean Sea and southeastern Gulf of Mexico. The forward speed of the system is likely to increase in 48 to 72 hours while it moves between the ridge and Tropical Storm Gamma to its southwest. After 72 hours, the cyclone is forecast to slow down and turn northward around the western portion of the ridge and a mid- to upper-level trough over the south-central United States. The track guidance is in relatively good agreement during the first 48 to 72 hours, but there is increasing spread thereafter. Users are reminded that the average 4- and 5-day NHC track forecast errors are about 160 to 200 miles at those time periods.

Key Messages:

  1. Tropical storm conditions are expected in the Cayman Islands beginning late Monday, and a Tropical Storm Warning is in effect.
  2. Dangerous storm surge and hurricane conditions are possible in portions of western Cuba and the Isle of Youth by Tuesday afternoon, and a Hurricane Watch is in effect.
  3. Heavy rainfall will affect portions of Hispaniola, Jamaica, the Cayman Islands, and western Cuba during the next few days and could lead to life-threatening flash floods and mudslides.
  4. The system is forecast to approach the northern Gulf Coast late this week as a hurricane. While there is large uncertainty in the track and intensity forecasts at these time ranges, there is a risk of dangerous storm surge, wind, and rainfall hazards along the coast from Louisiana to the western Florida Panhandle. Residents in these areas should monitor the progress of the system and check for updates to the forecast during the week.

Forecast discussion by NHC Forecaster Brown.

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