Zeta satellite image
Infrared satellite image of Tropical Storm Zeta over the western Caribbean at 11:30 a.m. EDT Sunday, October 25, 2020. The storm was beginning to build a central dense overcast (CDO) of high cirrus clouds over the center, the hallmark of an intensifying storm. (Image credit: RAMMB/CIRA/Colorado State University)

Tropical Storm Zeta formed in the western Caribbean early Sunday morning, with the potential to rapidly intensify into a hurricane that will make two landfalls: one on Monday night in Mexico’s Yucatan Peninsula, near Cancan; and one on Wednesday along the central Gulf of Mexico coast of the U.S., between Louisiana and the Florida Panhandle.

If this seems like déjà vu, you’re not mistaken: Hurricane Delta had a nearly identical forecast during the first week of October.

At 11 a.m. EDT Sunday, Zeta was stationary, spreading heavy rain showers over Jamaica, Cuba, and the Cayman Islands, as seen on Cayman Islands radar. A personal weather station on the west tip of Jamaica at Negril recorded 3.12 inches of rain between midnight and 12:30 p.m. EDT Sunday.

Satellite images showed that Zeta was not well-organized, with only one prominent spiral band along the east side of the center, and only a modest amount of heavy thunderstorm activity near the center. Water vapor satellite imagery showed Zeta had good upper-level outflow on all sides, but dry air over the Gulf of Mexico was apparent, and has the potential to slow development in coming days.

Figure 1
Figure 1. Radar image of Zeta at 11 a.m. EDT October 25. (Image credit: National Weather Service, Cayman Islands)

2020 parade of record-early named storms continues

Zeta’s October 25 arrival marks the earliest date that any Atlantic season has produced its 27th tropical storm, topping the record held by Epsilon from November 29, 2005 (an additional unnamed storm was added to 2005’s tally after the season was over). In total, 24 of 2020’s 27 named storms set records as the earliest-arriving for their respective letter; only Arthur, Bertha, and Dolly fell short.

With over five weeks still to go in the 2020 Atlantic hurricane season, there already have been 27 named storms, 10 hurricanes, four intense hurricanes, and an accumulated cyclone energy (ACE) index of 136 (42% above average for the date). Colorado State University hurricane scientist Phil Klotzbach says the averages for this point in the season are 10.8 named storms, 5.6 hurricanes, 2.5 intense hurricanes, and an ACE index of 96.

If Zeta makes landfall in the U.S. as a named storm, it would be the record-breaking 11th storm to do so this season. Prior to 2020, the highest number of tropical storms and hurricanes to make landfall in the continental U.S. was nine, in 1916.

Figure 2
Figure 2. Track forecasts out to five days for Zeta from the 6Z (2 a.m. EDT) Sunday, October 25, 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 Zeta. The weaker forecasts have Zeta making a more westerly landfall in Louisiana, with the stronger forecasts predicting a landfall in the Florida Panhandle. (Image credit: Tropical Tidbits)

Track forecast for Zeta

Steering currents are weak in the western Caribbean, and Zeta is expected to move northwest at less than 10 mph through Monday morning. A ridge of high pressure will strengthen to the northeast of Zeta on Monday and Tuesday, forcing it on a northwesterly track at a faster 10-15 mph pace through the Gulf of Mexico. By Tuesday, an approaching trough of low pressure over the central U.S. is expected to turn Zeta more to the north or north-northeast, with a landfall along the central Gulf Coast on Wednesday expected.

If Zeta is a weak to moderate-strength tropical storm, an outcome suggested by the European model and its ensembles on Sunday morning, a landfall in Louisiana is more likely, since Zeta will be steered more by the low-level flow, tending to take the storm to the north. If Zeta is stronger, at hurricane strength, it will “feel” the upper-level winds out of the southwest from the approaching trough. In that case, it will track more to the north-northeast, resulting in a landfall potentially as far east as the Florida Panhandle.

Figure 3
Figure 3. Predicted wind speed (colors) and sea level pressure (black lines) for Zeta at 11 p.m. EDT Monday, October 26, from the 6Z Sunday, October 25, run of the HWRF model. The model predicted that Zeta would be making landfall on Mexico’s Cozumel Island as a category 1 hurricane with 90 mph winds. (Image credit: Tropical Tidbits)

Intensity forecast for Zeta

Zeta will have favorable conditions for intensification through Tuesday, with light wind shear of 5-10 knots, ocean temperatures of 29.5-30 degrees Celsius (85-86°F), and a moist atmosphere with a mid-level relative humidity of 60-70%. Zeta will be passing over waters in the northwest Caribbean having the highest heat content of any waters in the North Atlantic – a strong basis for rapid intensification.

Also see: Climate change is causing more rapid intensification of Atlantic hurricanes

However, for it to take advantage of these favorable conditions, Zeta needs to overcome its current poor structure. Northerly upper-level winds on Sunday afternoon were creating about 10 knots of wind shear over Zeta, causing the storm’s vortex to tilt with height, and keeping most of the heavy thunderstorm activity restricted to the south side of the center of circulation.

Most of the top intensity models predicted with their Sunday morning runs that Zeta would intensify into a category 1 hurricane by Monday night, when the storm will make its closest approach to Mexico’s Yucatan Peninsula and the western tip of Cuba. If Zeta manages to pass through the Yucatan Channel between Mexico and Cuba, the storm will likely continue to intensify as it enters the Gulf of Mexico. However, if Zeta makes landfall in Mexico or Cuba, considerable disruption to the storm will likely occur, and Zeta may need a day or more to reestablish its inner core and re-intensify.

Figure 4
Figure 4. Ocean Heat Content (OHC) levels on October 6, with the 5 a.m. EDT advisory positions for Hurricane Zeta overlaid. The warm waters of the Loop Current lay over the western Caribbean, and Zeta is expected to pass over this high heat content water before moving over the northeast tip of the Yucatan Peninsula. Zeta will then move over continental shelf waters with limited heat content, but once in the central Gulf, will encounter OHC values of about 50 kilojoules per square centimeter (light green colors), before passing over waters with low heat content (blue colors) on approach to the U.S. Gulf Coast on Wednesday. OHC values in excess of 75 are highly favorable for rapid intensification of hurricanes. Near-shore waters along the continental shelf are too shallow to have a relevant number for OHC, and are left black in this image. (Image credit: University of Wisconsin CIMSS)

The 12Z Sunday run of the SHIPS model gave good odds that Zeta will undergo rapid intensification: a 32% chance that it would intensify by 30 mph by Monday morning (three times higher than the climatological odds), and a 30% chance that it would intensify 75 mph by Wednesday, into a category 3 hurricane (six times higher than the climatological odds).

The official National Hurricane Center forecast called for Zeta to achieve category 1 hurricane status on Tuesday morning. A reasonable uncertainty range for Zeta’s intensity on Monday night, during its closest approach to western Cuba and northeastern Mexico, is 60-100 mph sustained winds.

On Tuesday night and Wednesday, when Zeta will be approaching the U.S. Gulf Coast, the storm will encounter more hostile conditions for intensification. Waters beneath the storm will be significantly cooler, wind shear will rise, and dry air over the Gulf will have the opportunity to wrap into its core. However, a strong band of upper-level winds to the north of Zeta will provide a more efficient upper-level outflow channel as the storm approaches the coast, helping counteract the increased shear.

Sally, Laura, and Delta all encountered similar conditions when they made landfall earlier this year; Sally and Laura did not weaken before landfall, but Delta did. Expect Zeta to behave more like Delta, since the ocean temperature structure of the Gulf is similar to what Delta encountered. Zeta could be anywhere between a strong tropical storm and a category 2 hurricane at landfall in the U.S., with the official NHC forecast of a weakening category 1 hurricane with 75 mph winds a reasonable prediction.

Figure 5
Figure 5. GeoColor satellite image of Hurricane Epsilon at 10:40 a.m. EDT Sunday, October 25, 2020. (Image credit: RAMMB/CIRA/Colorado State University)

Hurricane Epsilon becoming extratropical

Hurricane Epsilon was steaming east-northeast at 30 mph at 11 a.m. EDT Sunday, and was maintaining hurricane status, with sustained winds of 75 mph and a central pressure of 960 mb. Epsilon is a large storm, with tropical storm-force winds that extended up to 380 miles to the north of the center. The large wind field was generating large swells, which will be affecting the U.S. East Coast and Atlantic Canada through Monday. Epsilon brought widespread rainfall amounts of 0.5-1.0 inches to southeast Newfoundland on Sunday morning, and winds gusted as high as 31 mph at the capital, St. Johns.

Epsilon will merge with a trough of low pressure to its north on Sunday afternoon and transition to a very powerful extratropical storm with winds near hurricane force. Its central pressure on Tuesday, October 27, when it will be a few hundred miles south of Iceland, could be between 935-940 mb, according to the 0Z Sunday runs of the GFS and European models.

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Posted on October 25, 2020 (1:39pm 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...

30 replies on “Tropical Storm Zeta, 27th Atlantic storm of the season, forms in western Caribbean”

  1. What happened to all the posters of Jeff M’s previous blog? I see only 20 comments. Unreal. There used to be 1000s! Is “Pat” from Cat 6 on here now?

  2. OK this makes what 111 for the NO area. Maybee we are getting a heads up we need to start slowly moving away from that port and all the gas that comes in there. I know it cannot be done in a day but look at satellite images of LA from the early 60s and compare to today. Hundreds of miles of salt water marsh are just gone and replaced with oil pipes.

    Yes we need to move slowly away from gas. We can not and should not do it overnight. A LOCAL politicization keeps talking about closing every oil well in America on Nov 4. all at once.

    Told him he was insane, America and then half the world would starve.

    The Control of NatureApril 1, 2019 Issue

    Louisiana’s Disappearing Coast

    The state loses a football field’s worth of land every hour and a half. Now engineers are in a race to prevent it from sinking into oblivion.

    By Elizabeth Kolbert

    March 25, 2019

    From the headline in The New Yorker 2019

    1. yes i wont be around then but a much different world is on the verge of beginning, a world without oil and Gas..will they or can they go all nuclear? i doubt it..can they go all electric? i doubt it..in a couple of weeks i’ll be 71..so i see the world i grew up in..is already mostly gone..its the younger people that will come to see quite possibly..Their world They grew up in be gone too…what kind of world will there be oh say 2050-2060-2070?..could be nothing we have now?….Doc this could be quite a topic for some later date. IF people today will stay awake and recognize what’s coming down the pike perhaps in Their lifetimes..and good luck to all when this Big change comes..surely it wont be pretty

      1. 4000 years ago people used crude sail boats in China. Leaf Erickson, Eric the Red, not so crude sailing ships,1000 years ago, Two hundred years ago, a very bad ass sailing ship called US Constitution, aka Old Iron Sides.

        USS Constellation is a sloop-of-war, the last sail-only warship designed and built by the United States Navy.

        USS Constellation (1854) – Wikipedia

        1958 USS Enterprise First Nuclear powered aircraft carrier,

        So we went from sails to steam engines in 4000 years.
        we went from steam engines to nuclear powered aircraft carriers
        in 165 years.

        What changed?

  3. one good thing for florida..nws is hinting that after the hurricane pulls inland, north of florida..a cold front might actually Make it here into Florida..Yesss!! lol…lets see if it really does and gets rid of these 90’s and high Humidity huh..

      1. According to my friend who has access to long range forecasts from some of the more reliable models, there is a 3% probability of snow for northern Florida from Dec.21-31. I had no ideal that such a long range forecast is possible but apparently it is. Personally, I live in Jupiter, FL, but I left my shovel up north and am not ready to go to Home Depot to get a new one yet. Merry Xmas!

  4. Being that we are in the Greek alphabet (only 2nd time I know of, 2005 the other), Will the next storm be Eta or Theta? Long rang models are making this an actual question. When 2020 is over, I am yelling Jamanji !!!!

  5. well this early Mon morning it seems like the models have got their act together and figured the storms track to LA/MISS area..still a few days away and like Doc said..lets see if the Yucatan weakens it or it slips thru and doesnt weaken over land..still a lil uncertainty huh..

  6. Japan Meteorological Agency
    Tropical Cyclone Advisory #21 – 9:00 AM JST October 26 2020
    Occidental Mindoro province area (Luzon/Philippines)

    At 0:00 AM UTC, Typhoon Molave (980 hPa) located at 13.2N 120.4E has 10 minute sustained winds of 65 knots with gusts of 95 knots. The cyclone is reported as moving west at 14 knots.

    Storm Force Winds
    40 nm from the center

    Gale Force Winds
    120 nm from the center in northeastern quadrant
    90 nm from the center in southwestern quadrant

    Dvorak Intensity: T4.0

    Forecast and Intensity
    12 HRS: 13.2N 117.9E – 75 knots (CAT 3/Strong Typhoon) South China Sea
    24 HRS: 13.6N 115.0E – 80 knots (CAT 3/Strong Typhoon) South China Sea
    48 HRS: 14.8N 109.8E – 75 knots (CAT 3/Strong Typhoon) South China Sea
    72 HRS: 15.3N 104.3E – Tropical Depression over land Thailand

    1. Nice to know what’s up in Japan. In my opinion, I am more interested in what might impact the Northern Hemisphere…but it’s a small world and an interesting one at that.

  7. Hi everyone. I admire and very much appreciate every single post from Dr Masters since so many years ago at the WU site. I live in Cancun so you can imagine I knwo what it is to to live through fun times such as Gilbert, Emily, Ivan, Wilma, and most recently Gamma/Delta and now Zeta, in just about 24 hrs from now!
    Any question or special input you can provide with regards to local impacts and forecasts, I will love to comment and provide local input. So now it all seems like Zeta will be a twin sister to Delta, but much slower, and hopefully a little weaker. How about cumulate rain? Delta was particularly quick for a cat 2 hurricane (scarcely 4 hours of hurricane force wind impact) and pretty dry, even compared to TS Gamma which poured good 11 inches of rain in less than 48 hours. If Zeta is cat 1-2 strong, but mush slower, and significantly wetter, it will is bound to create more havoc than Delta. David

  8. Dr.Jeff: Many thanks for the outstanding analysis of Zeta. I found especially interesting your explanation of how a weaker Zeta would tend to make landfall towards the west as per the Euro model whereas a stronger Zeta would tend to make landfall towards the east…perhaps the FL panhandle. You are the best!

  9. whew might have 2-3 days of this....................Flood Advisory
    National Weather Service Miami FL
    144 PM EDT Sun Oct 25 2020
    Broward FL-Miami-Dade FL-Palm Beach FL-
    144 PM EDT Sun Oct 25 2020
    The National Weather Service in Miami has extended the
    * Flood Advisory for...
      Broward County in southeastern Florida...
      Northern Miami-Dade County in southeastern Florida...
      Southeastern Palm Beach County in southeastern Florida...
    * Until 445 PM EDT.
    * At 144 PM EDT, heavy rain has diminished from earlier, though
      there is plenty of standing water in the advisory area and the
      potential for more activity exists. Periods of additional heavy
      rainfall on already saturated ground could lead to more impactful
      flooding within the advisory area.
    Some locations that will experience flooding include...
      Fort Lauderdale, Pembroke Pines, Hollywood, Miramar, Coral
      Springs, Pompano Beach, Davie, Plantation, Sunrise, Boca Raton,
      Deerfield Beach, Tamarac, Margate, Lighthouse Point,
      Lauderdale-By-The-Sea, Hallandale, Miami Gardens, Lauderhill,
      Coconut Creek and Oakland Park.
    A Flood Advisory means river or stream flows are elevated, or
    ponding of water in urban or other areas is occurring or is imminent.
    Turn around, don`t drown when encountering flooded roads. Most flood
    deaths occur in vehicles.
    LAT...LON 2597 8029 2633 8028 2633 8022 2633 8008
          2633 8007 2633 8006 2597 8011
  10. Thank you for the storm info Doc,so far they arent thinking it will be a real strong Hurricane,,so far anyway and we have about 3 more days yet

  11. Thanks for the Sunday update, Dr. Masters!

    To quote you above:
    “…Sally and Laura did not weaken before landfall, but Delta did. Expect Zeta to behave more like Delta, since the ocean temperature structure of the Gulf is similar to what Delta encountered.”

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