Tropical Depression 25 satellite image
GeoColor satellite image of TD 25 over the western Caribbean at 11:10 a.m. EDT Friday, October 2, 2020. (Image credit: RAMMB/CIRA/Colorado State University)

A Tropical Storm Warning is up for Mexico’s Yucatan Peninsula for the expected arrival on Saturday of Tropical Depression 25, which formed at 11 a.m. EDT Friday in the western Caribbean. Poised to strengthen into Tropical Storm Gamma by Saturday morning, TD 25 is a heavy rain threat to Mexico’s Yucatan Peninsula, Belize, and western Cuba. It poses no threat to the U.S. over the next five days.

Conditions for development of TD 25 are favorable through Saturday, with sea surface temperatures (SSTs) of 30 – 30.5 degrees Celsius (86 – 87°F), light wind shear less than 10 knots, and a moist atmosphere with a mid-level relative humidity of 80%. Satellite images showed that TD 25’s heavy thunderstorm activity was steadily increasing in intensity, areal coverage, and organization as the system moved northwest at about 9 mph. An Air Force hurricane hunter aircraft is to investigate TD 25 on Friday afternoon.

Figure 1
Figure 1. Track forecasts out to 10 days for the Gulf of Mexico from the 0Z Friday, October 2, run of the ensemble forecast of the European model. Most of the forecasts (color-coded by pressure) from the 51 individual members predicted that TD 25 would make landfall over the Yucatan Peninsula and remain trapped in the southwestern Gulf of Mexico. One of the 51 forecasts predicted that TD 25 would become a strong hurricane with a pressure of 960 mb or lower (red colors). (Image credit:

Forecast for TD 25

The ridge of high pressure steering TD 25 should keep it moving to the northwest or north-northwest through Sunday, a track on which all of the major computer models agree. This motion should bring TD 25 to the coast of Mexico’s Yucatan Peninsula on Saturday, though it is possible the system could slide just north of Cancun and pass through the Yucatan Channel between Cuba and Mexico. TD 25’s forward motion is expected to slow to less than 5 mph Saturday through Monday, resulting in very heavy rains.

The track of TD 25 next week is unclear, as it will be embedded in a region of weak steering currents. The current model consensus is that TD 25 will be a relatively weak storm steered slowly westwards by the low-level winds. If TD 25 manages to over-achieve and intensify into a hurricane over the weekend, a more northerly path and a potential threat to the U.S. could materialize.

Further complications on predicting TD 25’s track may arise next week as another tropical wave, now moving through the eastern Caribbean, arrives in the western Caribbean. In an 8 a.m. EDT Friday Tropical Weather Outlook, the National Hurricane Center gave this second tropical wave two-day and five-day odds of development of 0% and 30%, respectively.

Conditions for development of TD 25 will become more hostile on Sunday, when the system will encounter a large trough of low pressure extending from Mexico into the southeastern U.S., associated with a cold front that moved through the Gulf of Mexico early this week. This trough will bring high wind shear of 20 – 30 knots to TD 25 Saturday night through Monday. In addition, plenty of dry air over the Gulf of Mexico will interfere with development, as will land interaction with the Yucatan Peninsula.

Because of these obstacles, the models do not indicate that TD 25 will achieve hurricane strength over the next five days. Beyond five days, wind shear is likely to decrease and dry air will lessen, as the cold front and associated trough over the Gulf of Mexico weaken. These factors may allow TD 25 to intensify beyond the next five days.

Figure 2
Figure 2. Predicted rainfall amounts from the 6Z (2 a.m. EDT) Friday, October 2, run of the experimental HAFS model, for the period ending at 3Z Wednesday, October 7. The model predicted that TD 25 would dump more than 10 inches of rain (yellow-brown colors) along portions of Mexican and western Cuban coasts, and more than five inches (orange colors) in central Florida. (Image credit: NOAA/AOML)

Heavy rains possible in Florida

The trough of low pressure that TD 25 will encounter this weekend will also act to shunt tropical moisture from the system to the northeast over Florida. This is a favorable setup for what is referred to as a potential Predecessor Rain Event (PRE), which could bring heavy rain and flooding to parts of central Florida. The experimental HAFS model (Figure 2) is predicting more than five inches of rain over a five-day period for central Florida.

Figure 3
Figure 3. GeoColor satellite image of Hurricane Marie in the northeast Pacific at 11:20 a.m. EDT Friday, October 2. (Image credit: RAMMB/CIRA/Colorado State University)

Impressive category 4 Hurricane Marie churns in the northeast Pacific

In the northeast Pacific, over 1,000 miles west-southwest of Mexico’s Baja Peninsula, Hurricane Marie vaulted to category 4 status with 130 mph winds and a 948 mb central pressure at 11 a.m. EDT Friday morning.

Also see: Extreme events ‘presage worse to come’ in a warming climate

This intensity ties Marie with Hurricane Douglas of July and Hurricane Genevieve of August as the basin’s most intense hurricane of 2020. Marie still has a window of opportunity to intensify into a stronger storm on Friday before crossing into a region of cooler ocean temperatures and higher wind shear that will likely induce significant weakening beginning on Saturday. Marie is not a threat to any land areas.

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Posted on October 2, 2020 (1:27pm EDT).

Jeff Masters

Jeff Masters

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...

45 replies on “Tropical Depression 25 forms in the western Caribbean”

  1. Good morning everyone. Since I’m a fat fingered clutz I closed my tab to cat 6 comments. Could someone please post the link to the backdoor for me? Thank you.

  2. Hi all.
    I noticed that in the 8 AM EDT TWO the NHC is tracking an area of showers and thunderstorms associated with a surface trough. They assigned it with a 10% chance of development. I believe this trough is related to the remnants of Paulette. I have been tracking the remnant low of Paulette, and the 850 hPa vorticity maximum of ex-Paulette was trackable up until now. Am I missing something? If not, if the trough were to consolidate into a tropical cyclone, would this be named Paulette again, or would it be designated a new name?

    An area of disorganized showers and thunderstorms over the central 

    Atlantic more than 1000 miles east-southeast of Bermuda is 

    associated with a surface trough of low pressure. Some slow 

    development of this system is possible during the next couple of 

    days before it too encounters strong upper-level winds.

    * Formation chance through 48 hours…low…10 percent.

    * Formation chance through 5 days…low…10 percent.

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