Tropical Storm Eta Forecast To Rapidly Strengthen

Tropical Storm Eta continues to strengthen as it moves south of Jamaica, producing hazardous seas and heavy rainfall across the island. Eta is forecast to strengthen as it nears the coast of Nicaragua and Honduras, becoming a hurricane as it slows down on approach. This is forecast to set up a life-threatening rainfall event for parts of Central America, with a high flash flood and landslide threat.

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 directly 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 5:00 PM AST, the center of Tropical Storm Eta was located near latitude 14.9 North, longitude 78.9 West. Eta is moving toward the west near 15 mph (24 km/h), and this motion with some decrease in forward speed is expected tonight. A slower motion toward the west-southwest is forecast on Monday and Tuesday. On the forecast track, the center of Eta is expected to approach the northeastern coast of Nicaragua on Monday, and make landfall within the Hurricane Warning area in Nicaragua Monday night or early Tuesday. Eta is forecast to move inland over northern Nicaragua through early Wednesday.

Data from a NOAA Hurricane Hunter aircraft indicate that the maximum sustained winds have increased to near 65 mph (100 km/h) with higher gusts. Rapid strengthening is forecast during the next 24 to 36 hours, and Eta is expected to become a hurricane tonight, with additional strengthening likely until the hurricane makes landfall Monday night or early Tuesday.

Tropical-storm-force winds extend outward up to 140 miles (220 km) from the center. The latest minimum central pressure reported by NOAA reconnaissance aircraft is 992 millibars.

Tropical Storm Eta Forecast Track as of 5:00 PM AST Sunday 1st November 2020. (National Hurricane Center)
Tropical Storm Eta Forecast Track as of 5:00 PM AST Sunday 1st November 2020. (National Hurricane Center)

Watches & Warnings

Tropical Storm Eta Watches and Warnings as of 5:00 PM AST Sunday 1st November 2020. (National Hurricane Center)
Tropical Storm Eta Watches and Warnings as of 5:00 PM AST Sunday 1st November 2020. (National Hurricane Center)

A Hurricane Warning is in effect for:

  • The coast of Nicaragua from the Honduras/Nicaragua border to Sandy Bay Sirpi

A Tropical Storm Warning is in effect for:

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

A Hurricane Watch is in effect for:

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

A Tropical Storm Watch is in effect for:

  • The northern coast of Honduras from west of Punta Patuca westward to Punta Castilla

A Hurricane Warning means that hurricane conditions are expected somewhere within the warning area. A warning is typically issued 36 hours before the anticipated first occurrence of tropical-storm-force winds, conditions that make outside preparations difficult or dangerous. Preparations to protect life and property should be rushed to completion.

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

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

Interests elsewhere in Nicaragua and Honduras should monitor the progress of this system.

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 5:00 PM AST Sunday 1st November 2020, as well as the most likely time of arrival of tropical-storm-force winds. (National Hurricane Center)
Tropical Storm Eta probabilities for tropical-storm-force winds as of 5:00 PM AST Sunday 1st November 2020, as well as the most likely time of arrival of tropical-storm-force winds. (National Hurricane Center)

WIND: Hurricane conditions are expected in the Hurricane Warning area beginning Monday night, with tropical storm conditions possible in this area by Monday afternoon. Tropical storm conditions are expected in the Tropical Storm Warning area by Monday afternoon, and hurricane conditions are possible in the Hurricane Watch area by early Tuesday. Tropical Storm conditions are possible in the Tropical Storm Watch area by early Tuesday.

RAINFALL: Eta is expected to produce the following rainfall amounts through Friday afternoon:

  • Central and northern Nicaragua into much of Honduras: 15 to 25 inches (380 to 635 mm), isolated amounts of 35 inches (890 mm).
  • Eastern Guatemala and southern Belize: 10 to 20 inches (255 to 510 mm), isolated amounts of 25 inches (635 mm).
  • Portions of Panama and Costa Rica: 10 to 15 inches (255 to 380 mm), isolated amounts of 20 inches (510 mm).
  • Jamaica: 5 to 10 inches (125 to 255 mm), isolated amounts of 15 inches (380 mm) over southern areas.
  • Southern Haiti and the Cayman Islands: 3 to 5 inches (75 to 125 mm), isolated amounts of 10 inches (255 mm)

This rainfall would lead to significant, life-threatening flash flooding and river flooding, along with landslides in areas of higher terrain.

STORM SURGE: A dangerous storm surge will raise water levels by as much as 10 to 15 feet above normal tide levels in areas of onshore winds along the coast of Nicaragua within the hurricane warning area, and 3 to 5 feet above normal tide levels along the coast of Honduras within the tropical storm warning area. Near the coast, the surge will be accompanied by large and destructive waves.

SURF: Swells generated by Eta are expected to affect portions of the coast of Central America and the Yucatan Peninsula of Mexico during the next few days. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office.

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)

Eta has continued to quickly become better organized today with an increase in banding and the development of a central dense overcast feature. A NOAA Hurricane Hunter aircraft that has provided a couple of center fixes this afternoon has found a strengthening tropical storm. The aircraft has reported a minimum pressure of 992 mb and a 30 n-mi-wide eye that is open to the southwest. A blend of the SFMR and flight-level wind data support an initial wind speed of 55 kt for this advisory. Given the much improved inner-core structure as reported by the reconnaissance aircraft and the favorable environmental conditions of low vertical wind shear and high ocean heat content, additional strengthening is likely. The intensity guidance is much higher this cycle, and the various rapid intensification models show a much more significant chance of rapid strengthening over the next 24 to 36 hours. The DTOPS model indicates a 71 percent chance of a 30-kt increase in wind speed over the next 24 hours, while the SHIPS Rapid Intensification Index shows a 53 percent chance of a 45-kt increase over the next 36 hours. Based on the higher initial intensity and the more bullish guidance, the NHC intensity forecast has been increased and essentially calls for rapid strengthening until Eta reaches the coast of Central America. Once inland, Eta should quickly weaken over the mountainous terrain of Nicaragua and Honduras.

Eta is still moving steadily westward or 270 degrees at about 14 kt. A westward motion at a somewhat slower forward speed is expected tonight. On Monday, Eta is forecast to turn southwestward at a slower forward speed when a mid-level ridge builds to the north and northwest of the cyclone. Eta is forecast to move inland over northeastern Nicaragua within the Hurricane Warning area Monday night or early Tuesday. The dynamical models are in relatively good agreement through about 72 hours, expect for the HWRF which shows a more northern track and keeps Eta offshore for much of the period. This solution is considered an outlier at this time, and the NHC track is in good agreement with the various global models and the HFIP corrected consensus model. Some model solutions still suggest Eta or its remnants will re-emerge over the northwestern Caribbean Sea at or beyond day 5. The new NHC 5-day position is still inland near the Gulf of Honduras close to the various consensus aids, but large uncertainty exists in the forecast at that time range due to the large spread in the track guidance.

Key Messages:

  1. Eta is forecast to strengthen into a hurricane tonight, and additional strengthening is forecast before it reaches the northeastern coast of Nicaragua Monday night or early Tuesday, where a Hurricane Warning is in effect. A Tropical Storm Warning is in effect for a portion of the northeastern coast of Honduras.
  2. Through Friday afternoon, heavy rainfall from Eta will lead to significant, life-threatening flash flooding and river flooding across portions of Central America, along with landslides in areas of higher terrain. Flash and river flooding is also possible across Jamaica, Southern Haiti, and the Cayman Islands.
  3. A life-threatening storm surge, along with damaging waves, is expected along portions of the northeastern coast of Nicaragua near and to the north of where the center makes landfall. Water levels could reach as high as 10 to 15 feet above normal tide levels in some parts of the hurricane warning area. Preparations to protect life and property should be rushed to completion.

Forecast discussion by NHC Forecaster Brown.

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