Matt Lanza

Melissa’s slow path in the Caribbean likely to cause the most impactful storm of the 2025 season

In brief: Tropical Storm Melissa is unfortunately looking to be one of the most impactful storms of the Atlantic hurricane season, with several days of high-end impacts possible for places like Jamaica and Haiti. Risks of a high-end major hurricane, along with catastrophic rainfall exist in these areas through the weekend and into early next week. Melissa is not a threat to the U.S. at this time, though it may graze the Bahamas or Turks and Caicos on its way out next week.

Invest 98L was upgraded to Tropical Storm Melissa on Tuesday, in what looks like the beginning of the climax of the 2025 Atlantic hurricane season. The forecast track for Melissa is troublesome.

(NOAA/NHC)

Melissa is expected to crawl, I mean crawl in the central Caribbean over the next several days. Melissa is not terribly well organized this morning, though its satellite appearance is rather ominous. In fact, the center is fairly heavily displaced to the west within the deeper thunderstorm activity indicated by the brighter white and pink/purple colors on the satellite image below.

Melissa’s satellite presentation isn’t particularly aesthetic despite being ominous. (Tropical Tidbits)

Maximum sustained winds are 50 mph as of the 8 AM advisory. We’ll see if that nudges up for the 11 AM ET one. There is currently a Hurricane Watch for southwest Haiti from Port-Au-Prince to the border with the Dominican Republic. A Tropical Storm Watch is posted for Jamaica. These watches could be upgraded to warnings and/or adjusted further later today.

Melissa’s slow track forward

So where is Melissa going to go? The billion dollar question, of course. Yesterday, it seemed we had a consensus of slow-moving and eventually a sharp turn north or northeast, perhaps toward Hispaniola. That’s still on the table, but the key now may be the “slow-moving” aspect of it all. Over the next 2 days we’ll see very slow west-northwest movement and drift. By Friday morning, we expect to see Melissa sitting just southeast of Jamaica.

Euro ensemble, and various Google AI model members forecast on Friday morning. (Google Weather Lab)

A continued northwest-ward drift is expected to continue beyond Friday, but from there, it gets a lot more complicated. Steering currents are meager at best in the Caribbean, meaning that we may see Melissa drift west even beyond this weekend into next week. It may take until later next week for a strong trough in the upper atmosphere to actually capture Melissa and steer it north and out to sea.

Of course, if Melissa just continues slowly drifting west, that may mean days of impacts for places like Haiti and Jamaica and possibly even eastern Cuba, the Cayman Islands or portions of Nicaragua and Honduras.

How strong will Melissa get?

Oceanic heat content is always high in the Caribbean, but this year it’s very, very high.

Oceanic heat content anomaly in the Caribbean is the third highest we’ve seen this late in the season. (Brian McNoldy, University of Miami)

In fact, based on Argo buoy temperature reports from the Caribbean, 30°C water extends down about 180 feet below the surface of the Caribbean. It’s deep, rich, warm water. Particularly if for some reason this ends up west of Jamaica, the oceanic heat content there is incredibly high.

Truthfully, the only things that may inhibit intensification of Melissa is land and time. Wind shear is always a concern, but frankly, there’s nothing that stands out dramatically right now, certainly nothing that says this will falter. If Melissa drifts west to south of Jamaica where that patch of extreme oceanic heat content lies, we could easily be talking a category 4 or 5 storm.

Extreme levels of oceanic heat content exist south of Jamaica, possibly on the path of Melissa. (Brian McNoldy, University of Miami)

So steady intensification is likely for Melissa over the next couple days. Odds of rapid intensification upwards of 75 mph in the next 3 days are almost 5 times normal. Bottom line: There is likely to be continued intensification of Melissa and based on the track, the ceiling could be extremely high.

Rain forecast

Regardless of the track and intensity, someone, perhaps a lot of folks will see heavy, heavy rainfall in the Caribbean.

The rainfall forecast through Sunday shows upwards of a foot of rainfall for eastern Jamaica, as well as the south coasts of Haiti and the Dominican Republic. (NOAA WPC)

When all is said and done next week, it is not out of the realm of the possible for some places to see 20 inches (500 mm) or more of rainfall. This could be catastrophic in some places, including portions of Jamaica and Haiti or the southern Dominican Republic as well. Just really bad news with a slow-moving Melissa.

In summary:

  • Melissa is going to move slowly over the next 5 to 7 days over some of the warmest, deepest warm water in the Atlantic Basin.
  • Intensification into a hurricane and major hurricane seems likely at this point, with a high-end category 4 or 5 in the realm of the possible.
  • Impacts may be severe depending on the exact proximity of the storm to Haiti and Jamaica.
  • Heavy rain, flooding, mudslides, and severe water impacts are possible, if not likely in portions of Jamaica, Haiti, and the Dominican Republic.
  • All areas in this region should be prepared for multiple days of high-end impacts.
  • The storm is not expected to threaten the US, but it will eventually turn north and northeast into the Atlantic, possibly impacting the Bahamas or Turks and Caicos Islands on the way out.

More to come on this, possibly later if time allows.

On the cusp of Melissa, a potentially serious storm is on tap for parts of the central and western Caribbean

In brief: Invest 98L should become Tropical Storm Melissa by later today. It is going to slam on the brakes and meander in the central Caribbean for several days, with potential to become a strong hurricane. It will also be a tremendous rainmaker for somewhere, depending on exactly where it stalls out. Interests from Jamaica and Cuba, across Hispaniola, and into western Puerto Rico should continue monitoring Invest 98L.

Invest 98L is on the cusp of becoming a defined entity this morning.

Invest 98L is about to cross the threshold from Invest to depression or storm. (Weathernerds.org)

NHC odds are up to 100 percent for development, which based on the 4 semesters of Calculus I took in college, don’t get any higher.

Over the next few days there should not be a whole lot to interfere with 98L’s organization. In general, we should see slow, steady development. There’s been no real significant change in SHIPS model guidance for rapid development, showing about a 4.5x chance of that compared to climatology over the next 3 days, mostly unchanged from Monday.

One inhibiting factor to 98L’s growth and development may be the presence of dry air on the west side of the system.

European model forecast of dry air on Thursday, showing quite a bit of it on the north and west side of the system. (Tropical Tidbits)

I guess the question is whether the core of 98L can insulate itself enough from this to more rapidly develop, whereas the broader circulation of the system may be a little lopsided and skewed to the east of the center. We’ll see about that.

So with all that being said, what happens here? In terms of track and path forward, it appears that slower guidance may win out. Steering currents look meager at best, and 98L will probably be drifting westward now. Over the next 36 to 48 hours, agreement is decent in having a developing system drifting west or west-northwest to a position a few hundred miles southeast of Jamaica. From there, we stretch things out.

A fairly wide spread in possible outcomes by Friday evening in the Caribbean. (Google Weather Lab)

Now, that said, the red hot Google AI model seems to favor a position mostly south of Haiti, while the historically decent European ensemble is much more strung out between the Colombian isle of San Andres and the Turks and Caicos Islands. But even the AI modeling sees a widening spread in outcomes beyond Friday. A couple things do stand out in the model guidance today, the signal in the noise if you will. First, slow movement. The system is going to meander it appears, and I think the idea of a rapidly turning and moving storm into the Turks and Caicos by Friday or Saturday is unlikely at this point. Second, intensification. It would seem that with slower movement over a toasty Caribbean will produce steady intensification over the next 5 days. Rapid intensification is possible. We could be looking at a major hurricane by the weekend sitting somewhere south of Hispaniola or southeast of Jamaica.

An aspect that needs to be addressed? Rainfall. The stall position will have a tremendous impact on how much rain falls in parts of the Caribbean. For example, the European model stalls the storm east of Jamaica and drifts it west through day 7. Thus, you see a substantial amount of rain (8 to 12 inches or 200-300 mm) in eastern Jamaica, southern Haiti, and the southern Dominican Republic. If the storms stalls closer to Hispaniola, you could be talking 15 to 20 inches of rain or more in spots there.

Regardless of development, this looks like a potentially massive rain event for portions of the Caribbean. (Weathernerds.org)

So, I think we need to prepare for the potential for severe flooding and mudslide issues in parts of the central and western Caribbean by this weekend.

Bottom line today? Expect a tropical storm (Melissa) by later today. A slow moving storm is likely in the Caribbean. It is possible that a major hurricane can form from this. Regardless of development, major rains are possible, if not likely in portions of the Caribbean, particularly for eastern Jamaica, eastern Cuba, and Hispaniola. Eventually, this system should track north and east out of the Caribbean and into the open Atlantic, but that may not be until next week sometime.

Invest 98L may be pulling itself together fairly quickly in the Caribbean this week

In brief: Invest 98L is looking healthy this morning. We should probably anticipate a depression or tropical storm by later today or tomorrow. From there, it may stay buried in the Caribbean — or as Google’s AI modeling suggests, it will stall and intensify and come northward toward Hispaniola. Whatever the case, 98L bears close watching in the Caribbean this week.

Invest 98L in the Caribbean

Invest 98L remains a rather robust tropical wave this morning, probably the most impressive Caribbean wave this year.

Invest 98L moving into the Caribbean this morning. (Weathernerds.org)

I don’t know that this is yet a depression or storm, but let’s just say we’ve seen lesser systems be upgraded this season. I wouldn’t be shocked to see something happen here before the end of today.

For now, NHC odds are up to 80 percent. It’ll be interesting to see what happens here. The general rule of thumb is that a system that intensifies quicker will be more apt to turn poleward (to the north) faster. A weaker system would be more likely to remain buried in the southern Caribbean. If this is indeed intensifying and forming, we could quickly see a tap on the brakes, stall out for a bit, intensify, and turn due north or north-northeast back toward Hispaniola. You can see the split in model guidance this morning, with Google’s AI ensemble stronger and turning more northward faster than many European ensemble members that are generally weaker.

Google AI ensemble members are tracking farther north toward Hispaniola compared to the weaker Euro ensemble which is mostly remaining in the Caribbean. (Weathernerds.org)

The AI ensemble may have the edge here given the satellite presentation of 98L this morning, because it’s been the best performing model this season, and from what we’re seeing in SHIPS guidance today, showing over 4 times greater than average risk of rapid intensification in the 72 hour forecast timeframe.

Odds of rapid intensification of 65 kts (75 mph) in 72 hours is over 4 times climatology with Invest 98L, not an outlandish number but certainly with higher than average odds. (Polarwx.com)

While the idea of a weaker, farther south and west tracking system is valid, I think the odds definitely favor the potential for a much stronger system right now. The big question is whether the fair bit of westerly shear it is experiencing right now will fundamentally hold back the system from developing rapidly. Something like lots of bark and a little bite. In that instance, the system could also turn north as well, but it would be sloppier and more ragged.

Whatever the case, it is prudent right now for Hispaniola to begin taking this system quite seriously. While none of the explicit modeling forecasts a major hurricane right now, we know from history and observation of the current warm water in the Caribbean that intensity forecasting could be underdone, perhaps significantly. This will continue to bear close watching over the next few days.

A sample of storms that have tracked from a similar area over the years in October and November. (NOAA)

This is not an uncommon pathway to impact. We’ve seen memorable storms come out of this part of the Caribbean this time of year, including Sandy in 2012, Matthew in 2016, Hazel in 1954, and Tomas in 2010. Obviously, when noting Sandy and Matthew and Hazel, some folks on the East Coast may get jitters, but at this point in time, we expect this system to follow some of the eastern-most tracks on the map above, keeping it away from the East Coast.

We will continue to monitor Invest 98L and its potential impacts and have another update for sure tomorrow and perhaps this evening if necessary.

Caribbean development odds nudge up, and we’re watching a potential significant Lower 48 autumn pattern change in 8 to 12 days

In brief: Caribbean development odds from Invest 98L are increasing this week, but there are far too many questions than answers on its possible future in the Caribbean. We also take a look today at what could be a forthcoming significant pattern change for much of the Lower 48 just before Halloween, with an atmospheric river in the Northwest and the coolest air of the season so far in parts of the East and Central U.S.

Caribbean cruising with Invest 98L

The area we’ve been watching for the Caribbean over the last week or so is now up to a 60 percent chance of development and is classified as Invest 98L.

60 percent odds of development exist in the Caribbean later this week. (NOAA/NHC)

As this races into the Caribbean, it probably won’t develop. However, by the time it gets about halfway across the Caribbean it will begin to slam on the brakes. This is a fairly common behavior of a tropical wave this late in the season. Once it slows down, then all bets are kind of off. We could see slow development into a tropical storm or hurricane. We could see slow, erratic movement. We could see nothing happen at all.

By the time we get to Thursday evening, Invest 98L will be somewhere in the central or southwestern Caribbean. (Google Weather Lab)

Based on the combination of Euro ensemble and Google AI modeling, it would appear that by Thursday evening, whatever Invest 98L will be is somewhere between the southwest Caribbean and Hispaniola. Some ensemble members keep hooking this north and northeast across Hispaniola or Cuba and out to sea. Others keep it buried in the Caribbean for a few days, eventually threatening Honduras or Nicaragua. Others still keep just drifting it northwest toward the far western Caribbean before eventually turning back north and northeast. It is unlikely to get into the Gulf given the time of year.

Given how warm the Caribbean is, and given the uncertainty of the track, it would be best for all folks from Nicaragua and Honduras up to Cuba, the Caymans, and Jamaica over to Hispaniola to monitor the progress of this disturbance through the week. Yes, large storms can form in the Caribbean in late October. Stay tuned

Major U.S. pattern change on the horizon?

We’re starting to see signs of a major shift in the weather during Halloween week, so beginning in about 8 days or so. You can see the change in the upper air pattern when we look at the Euro ensemble about 20,000 feet up from day 5 through day 11:

A significant push of moisture and cool air in the West (blue) will expand into the central and Eastern U.S. by the 29th or 30th.

The 8-to-14-day outlook is highlighting a major precipitation event in the West that seems plausible with that upper air pattern.

The 8-to-14-day hazards outlook. (NOAA CPC)

In fact, you can see that precipitation anomalies as forecast by the European model are much above average in the Pacific Northwest for the 7 day period ending on the evening of October 29th.

Precipitation anomalies for the 7-day stretch ending on the evening of October 29th. (Tropical Tidbits)

An atmospheric river will get things going here. Eventually, that will send a disturbance across the country, allowing for colder air to dump in from Canada. Much of the South has yet to have that “Wow, here’s autumn!” front yet, while much of the North has had some periodic colder temperatures. But it does appear that things will change next week with this system and cold front. Kansas City hit 43 this morning, their coolest morning of the season, but the current blended model forecast for Halloween is calling for 30s.

Kansas City should have their coolest morning of autumn right around Halloween. (Open Meteo)

We’ll see just how far south and east this can get, but it’s possible we see 40s in Dallas and Atlanta as well from this front (though Atlanta will probably see 40s tonight as well for the first time). Either way, it appears that at least a temporary pattern change is on the way for the Lower 48. Whether that sustains into November or we fall back into a milder stretch again remains to be seen.