Tropical Depression Twenty-Eight Forms In The Northwestern Caribbean

Tropical Depression Twenty-Eight has formed in the northwestern Caribbean Sea, becoming the 28th tropical cyclone for 2020. This system is forecast to strengthen into a tropical storm over the next 72 hours as it moves between Cuba and the Yucatán Peninsula of Mexico.

If this system strengthens into a tropical storm, it will be named Zeta, becoming the earliest 27th named storm in Atlantic History, edging out 2005’s version of Epsilon which formed on November 29th. The last and only time Zeta was used was on December 30th, 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 Zeta.
List of names for the 2020 Atlantic Hurricane Season. The next named tropical cyclone will be called Zeta.
List of Greek names for the Atlantic Hurricane Season. The next named tropical cyclone will be called Zeta.
List of Greek names for the Atlantic Hurricane Season. The next named tropical cyclone will be called Zeta.

At 5:00 PM AST, the center of Tropical Depression Twenty-Eight was located near latitude 18.7 North, longitude 83.0 West. The depression is moving toward the north-northwest near 2 mph (4 km/h), and this motion is expected to continue through early Sunday. The system should gradually turn toward the west-northwest with a faster forward speed by Monday. On the forecast track, the center of the depression is anticipated to remain south of Cuba tomorrow and approach the Yucatan Channel or Yucatan Peninsula late Monday before emerging into the southern Gulf of Mexico on Tuesday.

Maximum sustained winds are near 30 mph (45 km/h) with higher gusts. Slow strengthening is forecast during the next 72 hours, and the system is expected to become a tropical storm on Sunday and could become a hurricane over the southern Gulf of Mexico on Tuesday. The estimated minimum central pressure based on NOAA Hurricane Hunter aircraft data is 1005 millibars.

Tropical Depression Twenty-Eight Forecast Track as of 5:00 PM AST Saturday 24th October 2020. (National Hurricane Center)
Tropical Depression Twenty-Eight Forecast Track as of 5:00 PM AST Saturday 24th October 2020. (National Hurricane Center)

Watches & Warnings

Tropical Depression Twenty-Eight Watches and Warnings as of 5:00 PM AST Saturday 24th October 2020. (National Hurricane Center)
Tropical Depression Twenty-Eight Watches and Warnings as of 5:00 PM AST Saturday 24th October 2020. (National Hurricane Center)

A Tropical Storm Watch is in effect for:

  • Pinar del Rio, Cuba

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

Interests in the Yucatan Peninsula should monitor the progress of the depression.

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

Hazards Affecting Land

Tropical Depression Twenty-Eight probabilities for tropical-storm-force winds as of 5:00 PM AST Saturday 24th October 2020, as well as the most likely time of arrival of tropical-storm-force winds. (National Hurricane Center)
Tropical Depression Twenty-Eight probabilities for tropical-storm-force winds as of 5:00 PM AST Saturday 24th October 2020, as well as the most likely time of arrival of tropical-storm-force winds. (National Hurricane Center)

RAINFALL: Across portions of central and western Cuba, the Cayman Islands, Jamaica, the northeast Yucatan Peninsula of Mexico, southern Florida, and the Florida Keys, storm total rainfall of 4 to 8 inches with local amounts of 12 inches are possible through Wednesday.

WIND: Tropical-storm conditions are possible in the watch area on Monday.

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

Tropical Depression Twenty-Eight Forecast Discussion

Tropical Depression Twenty Eight (Weathernerds.org)

Satellite imagery and NOAA Hurricane Hunter aircraft data indicate that the broad area of low pressure that NHC has been following for the past couple of days has consolidated enough to be considered a tropical depression. GOES-16 1-minute data shows the center pretty clearly, with a new area of convection close by, and a minimum pressure of 1005 mb was reported by the aircraft in that area. The surface winds were generally fairly light within about a degree of the center, but data from the plane supports a 25-kt initial intensity.

The tropical depression hasn’t been moving much, but recently it has started at least drifting toward the north-northwest. A shortwave trough moving across the southeastern United States should keep the cyclone in a rather weak steering pattern during the next day or so, with only a northwest drift anticipated. Mid-level ridging should build over the northern Gulf of Mexico on Monday, forcing the depression to move faster to the west-northwest toward the Yucatan Peninsula or Channel. The ridge shouldn’t last too long, however, with a substantial upper-level low forecast to eject out of the southwestern United States in a few days, causing the tropical cyclone to sharply turn to the north and northeast on Wednesday. The guidance isn’t in very good agreement, and these types of trough ejection scenarios can have significant timing differences. At this time, the NHC track forecast leans a little more on the global models than the regional hurricane models, and is just west of the model consensus.

While the large-scale shear is fairly light at the moment, the low- and mid-level circulations of the depression are not well-aligned. Thus, it might take some time for the system to strengthen despite low shear and very warm waters. In a day or two, the depression will likely have a structure that supports a faster rate of strengthening, and the intensification rate is increased while the cyclone is near the Yucatan. Although the forecast shows the system reaching hurricane strength in the southern Gulf of Mexico, this is rather uncertain given the potential land interaction and only a narrow area of favorable upper-level winds. A combination of cooler shelf waters and increasing shear will likely weaken the cyclone below hurricane strength as it approaches the northern Gulf Coast. However, strong tropical storms can still produce significant storm surge, rainfall, and wind impacts, and residents in this region will yet again need to monitor another tropical cyclone moving northward across the Gulf.

KEY MESSAGES:

  1. The depression is forecast to strengthen to a tropical storm Sunday and could bring tropical storm conditions to extreme western Cuba on Monday, where a Tropical Storm Watch is in effect. There is also a risk of tropical storm conditions in the northern Yucatan Peninsula of Mexico Monday night and Tuesday.
  2. Through Wednesday, heavy rainfall is expected across portions of central and western Cuba, the Cayman Islands, Jamaica, the northeast Yucatan peninsula of Mexico, southern Florida, and the Keys. This rainfall may lead to flash flooding in urban areas.
  3. The system is forecast to approach the northern Gulf Coast as a tropical storm on Wednesday and could bring storm surge, rainfall, and wind impacts to areas from Louisiana to the Florida Panhandle. Residents in these areas should monitor the progress of the depression and updates to the forecast.

Forecast discussion by NHC Forecaster Blake.

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