Tropical Storm Eta Forms Southeast of Jamaica

In just six hours after Tropical Depression Twenty-Nine formed, the tropical cyclone strengthened into Tropical Storm Eta southeast of Jamaica, becoming the 28th named storm in the Atlantic for 2020. This system is forecast to strengthen into a hurricane over the next 72 hours, with rapid strengthening possible as it nears coastal Central America.

With the formation of Eta, 2020 has now tied 2005’s record for the most number of tropical storms at 28. It has not broken the number of tropical depressions, which is at 28 for 2020 while in 2005, 31 tropical depressions formed.

Eta has become the earliest 28th named storm in Atlantic history, edging out 2005’s version of Zeta which formed on December 30th. This is the first time Eta has been used in Atlantic history.

This tropical cyclone is not forecast to impact Trinidad, Tobago, or the Lesser Antilles. The tropical wave did produce floods, gusty winds, and landslides across parts of Barbados, St. Vincent, and St. Lucia over the past week.

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

At 11:00 PM AST, the center of Tropical Storm Eta was located near latitude 15.0 North, longitude 74.2 West. Eta is moving toward the west near 15 mph (24 km/h) and this motion is expected to continue through Sunday night or Monday morning. A slower motion toward the west-southwest and then southwest is forecast on Monday and Tuesday. On the forecast track, the center of the cyclone is expected to be near the northeastern coasts of Nicaragua and Honduras by Monday night.

Maximum sustained winds have increased near 40 mph (65 km/h) with higher gusts. Additional strengthening is forecast, and Eta is expected to become a hurricane by Monday.

Tropical-storm-force winds extend outward up to 60 miles (95 km) from the center. The estimated minimum central pressure is 1005 millibars.

Tropical Storm Eta Forecast Track as of 11:00 PM AST Saturday 31st October 2020. (National Hurricane Center)
Tropical Storm Eta Forecast Track as of 11:00 PM AST Saturday 31st October 2020. (National Hurricane Center)

Watches & Warnings

Tropical Storm Eta Watches and Warnings as of 11:00 PM AST Saturday 31st October 2020. (National Hurricane Center)
Tropical Storm Eta Watches and Warnings as of 11:00 PM AST Saturday 31st October 2020. (National Hurricane Center)

A Hurricane Watch is in effect for:

  • The northeastern coast of Honduras from Punta Patuca to the Honduras/Nicaragua border.
  • The northeastern coast of Nicaragua from the Honduras/Nicaragua border to Puerto Cabezas

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.

Interests elsewhere in Nicaragua and Honduras should monitor the progress of this system. Additional watches or warnings will likely be required for portions of these countries later tonight or on Sunday.

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

Hazards Affecting Land

Tropical Storm Eta probabilities for tropical-storm-force winds as of 11:00 PM AST Saturday 31st October 2020, as well as the most likely time of arrival of tropical-storm-force winds. (National Hurricane Center)

RAINFALL: Through Thursday evening, Eta is expected to cause 5 to 10 inches of rain, with local 15-inch amounts, across Jamaica, the Cayman Islands, and possibly the southern coast of Hispaniola. Across portions of Central America, 10 to 15 inches of rain, with local amounts to 25 inches are expected. This rainfall may lead to flash flooding and river flooding and could lead to landslides in areas of higher terrain.

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

Tropical Storm Eta Forecast Discussion

Tropical Storm Eta (Weathernerds.org)
Tropical Storm Eta (Weathernerds.org)

Satellite imagery indicates that shower activity associated with the cyclone continues to become better organized, with a convective band wrapping about halfway around the center. Satellite intensity estimates from TAFB and SAB have increased to 35 kt, and the CIMSS satellite consensus is near 40 kt. Based on these data, the depression is upgraded to Tropical Storm Eta, the twenty-eighth named storm of the 2020 season. This ties the record for storms set in the 2005 season and is the first time the name Eta has been used in the Atlantic basin.

The initial motion is 275/13. A low- to mid-level ridge axis that extends from the subtropical Atlantic southwestward to Cuba and the Bahamas is currently the main steering influence, and the model guidance is in good agreement that this feature should cause the storm to move westward for the next 24-36 h. Between 36-72 h, a building low- to mid-level ridge over the Gulf of Mexico should cause Eta to turn west-southwestward as it approaches the coasts of Nicaragua and Honduras. Beyond that time, there remains significant spread in the models, with the GFS showing a slow motion toward the northwest near the coast of Honduras while the ECMWF/UKMET show a continued west-southwestward motion into the
Pacific. Given the spread, the NHC official track forecast shows a slow motion on days 3 through 5 and brings the cyclone’s center slowly across portions of Nicaragua and Honduras. The new forecast track is close to the multi-model consensus, and the 72-120 h part remains low confidence.

Eta is over warm water and is in an environment of light vertical wind shear. These conditions are expected to continue until the system nears the coast of Central America on 60-72 h. Thus, steady to possibly rapid strengthening is expected, with the storm forecast to reach hurricane strength between 36-48 h. The intensity guidance has trended stronger since the last advisory, and this part of the new intensity forecast is now a little below the intensity consensus. After 72 h, the intensity forecast is tied to whether or not the cyclone’s center moves inland over Central America, and the current forecast is based on the forecast track that takes the center well inland.

Key Messages:

  1. The depression is expected to strengthen to a hurricane early next week as it approaches the coast of Central America late Monday and Monday night, and there is a risk of storm surge, hurricane-force winds, and heavy rainfall for portions of Nicaragua and Honduras where Hurricane Watches have been issued. Hurricane warnings could be needed for portions of those areas on Sunday.
  2. Through Thursday evening, heavy rainfall from Eta may lead to flash flooding and river flooding across portions of Jamaica, the Cayman Islands, and Central America, which could lead to landslides in areas of higher terrain. Flooding is also possible near the southern coast of Hispaniola, depending upon the track of the storm.

Forecast discussion by NHC Forecaster Beven.

Facebook Comments