Satellite image
GeoColor satellite image of 96L at 10:50 a.m. EDT Friday, October 30. (Image credit: RAMMB/CIRA/Colorado State University)

A tropical wave, designated 96L by the National Hurricane Center on Thursday night, is moving west at 10-15 mph through the eastern Caribbean. The wave is producing a moderate amount of heavy thunderstorms that have grown organized over the past day, and 96L is likely to develop into Tropical Storm Eta by Monday.

Conditions for development for 96L were favorable on Friday. Sea surface temperatures (SSTs) were a warm 29 degrees Celsius (84°F), about 0.6 degrees Celsius (1.0°F) above average; wind shear was light, 5-10 knots; and 96L was embedded in a moderately moist atmosphere with a mid-level relative humidity of 65%.

By Monday, when 96L will be in the western Caribbean southwest of Jamaica, conditions for development will still be favorable, with SSTs of 29.5 degrees Celsius (85°F), wind shear a moderate 10-15 knots, a moist atmosphere with a mid-level relative humidity of 75%.

Figure 1
Figure 1. Track forecasts out to seven days for 96Lfrom the 6Z (2 a.m. EDT) Friday, October 30, run of the GFS ensemble model (GEFS). The black line is the mean of the 31 ensemble members; individual ensemble member forecasts are the thin lines, color-coded by the central pressure they predict for 96L. Most of the members predicted a westward track into Nicaragua. (Image credit: Tropical Tidbits)

Forecast for 96L

In 0Z and 6Z Friday runs, the top three models for predicting tropical cyclone genesis all saw 96L developing into a tropical depression or tropical storm by Monday. The models predicted 96L would be trapped by a strong ridge of high pressure to its north, which would force the storm on a generally westward motion, resulting in a landfall in Nicaragua or Honduras sometime Monday through Wednesday. Fewer than 10% of the 82 ensemble members of the Friday morning runs of the European and GFS ensemble forecasts predicted that 96L might turn north and threaten Cuba.

The uncertainty on the timing of a potential landfall for 96L results from the steering currents that will weaken on Monday, when 96L will enter the western Caribbean, resulting in its slower forward speed of 5-10 mph. In an 8 a.m. EDT Thursday Tropical Weather Outlook, NHC gave 96L 2-day and 5-day odds of development of 70% and 80%, respectively. The next name on the Atlantic list of storms is the seventh letter in the Greek alphabet, Eta. If Eta does form, it would tie 2020 with 2005 for the most named storms in an Atlantic hurricane season, with 28. One of the storms in 2005 was not named because it was discovered in post-season analysis, so this would be the first use of Eta in any Atlantic season. The first Hurricane Hunter mission into 96L will likely occur no later than Sunday afternoon.

Figure 2
Figure 2. Hurricane Zeta near landfall in Louisiana on October 28, as seen from the International Space Station. (Image credit: NASA)

The recovery from Hurricane Zeta continues

At least six people died in the southeastern U.S. in the aftermath of Hurricane Zeta, which made landfall in southeastern Louisiana at 4 p.m. CDT October 28, as a category 2 storm with 110 mph winds. According to the latest write-up on Zeta, a New Orleans man was electrocuted by low-hanging power lines. In Mississippi, a man taking video of the storm in Biloxi drowned at a marina, the Sun Herald reported. In Georgia, three people died after trees fell on their homes. One person also died in Alabama when a tree fell on a home, the Associated Press reported.

According to, 1.4 million customers were without power on Friday morning along the path of the hurricane, down from the peak of 2.6 million customers on Thursday.

Also see: Hurricane Zeta’s high winds cause largest U.S. power outage of 2020

NHC announced Thursday that the highest coastal inundation observed from Zeta’s storm surge occurred in Ocean Springs, Mississippi, with 9-10 feet of inundation. This surge was very much in line with the NHC forecast, which called for peak inundation levels of 8-11 feet.

We plan a second post later today on category 5 Super Typhoon Goni, as it heads toward the Philippines.

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Posted on October 30, 2020 (12:29pm EDT).

Jeff Masters, Ph.D., worked as a hurricane scientist with the NOAA Hurricane Hunters from 1986-1990. After a near-fatal flight into category 5 Hurricane Hugo, he left the Hurricane Hunters to pursue a...

27 replies on “Tropical Storm Eta likely to form in the Caribbean by Monday”

  1. Thanks for the warning — I forwarded it to a friend who is now flying south from Costa Rica to connect in Panama for his flight to Boston. There are a million ways your work has helped people, and I hope it has also brought you much reward. Cheers!!!

  2. High mountains, excessive rainfall a good mix does not create. Mitch formed in the same area as Eta in 1998 and after weakening went inland into Honduras and Nicaragua. Some estimates of totals as the clouds were blocked by high elevation mountains were as much as 75″ of rain. Over 11,000 confirmed fatalities and well over 11,000 missing and never confirmed as survivors.

    1. The rain from Mitch devastated Costa Rica, where survivors recall watching cows wash off the mountains into the Pacific. Eta is no Mitch…cross em if you got em.

  3. NHC disc (clipped)…some model solutions indicate the
    potential for Eta or its remnants to re-emerge over the northwestern
    Caribbean Sea at or beyond day 5. For now, the official NHC forecast
    remains close to the previous one and the corrected consensus aid
    HCCA, which keeps the cyclone inland over Central America through
    day 5.

    1. Hi Art__ You seem to be a very knowledgeable voice of reason. As you know, the NHC has the track of TD29, formerly 96L, in basic agreement with the Euro model and several others rather than the GFS solution which is rather convoluted and a bit scary for us FL folks. But the NHC did hedge their bets, and rightly so, that “significant” changes could be made going forward dependent on future model runs.I would also be interested in what some of the other models have to say, e.g., COMPAS, NAVGEM, HWRF, as they are excellent track models as you know.Keep up the good work.

  4. Why is the GFS looking so ominous this morning? I’m in Key West and wondering if this could really happen in November?

    1. lets wait a few days, i like the GFS but none of the other models do that..all go into central far 8 days anything can happen route change wise

    Tropical Weather Outlook
    NWS National Hurricane Center Miami FL
    800 PM EDT Fri Oct 30 2020
    For the North Atlantic...Caribbean Sea and the Gulf of Mexico:
    1. A tropical wave located over the eastern Caribbean Sea is producing 
    a concentrated area of showers and thunderstorms. This system is 
    slowly becoming better organized, and conditions appear conducive 
    for further development. A tropical depression is likely to form 
    this weekend as the system moves westward across the central and 
    western Caribbean Sea. Regardless of development, this system is 
    expected to produce heavy rainfall across portions of the ABC 
    islands and Jamaica through the weekend.
    * Formation chance through 48 hours...high...80 percent.
    * Formation chance through 5 days...high...90 percent.
    Forecaster Beven
  6. Did anyone look at the latest GFS loop?? Around 200+ hours it is a big pencil eraser, going back and forth, over south Florida. Fortunately, none of the other models have that kind of solution….

  7. I would never disagree with Dr. Jeff, but he is focused on the GFS. I love the GFS too, but the Euro model has the storm at 120 hours as a remnant low. So, one of the models is right no doubt. Which one? We will know more once a tropical depression forms, and the models get their act together. I hope that the Euro is right this time. We do not need another landfalling hurricane in the U.S. this year. God help us.

  8. Area Forecast Discussion
    National Weather Service Newport/Morehead City NC
    1230 PM EDT Fri Oct 30 2020

    A strong cold front will continue to move further offshore this
    afternoon. Cool high pressure will build in Saturday through
    Sunday. A strong cold front will cross the area Sunday night
    followed by cold high pressure into the middle of next week.


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