Matt Lanza

Tropical Depression 19 will be a deeply serious flooding threat for Honduras

Headlines

  • Tropical Depression 19 should become Sara later today.
  • Sara will be a deeply serious flooding threat to coastal Honduras.
  • The odds of a major hurricane, in particular a major hurricane tracking toward Florida have dropped off since yesterday.
  • There is still substantial uncertainty surrounding the details of Sara’s development and peak intensity, but broadly a drift/stall near the coast of Honduras through the weekend, followed by a track toward Belize and the Yucatan and then a hook northeast toward Florida is favored.
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On with the show…

TD 19 is going to hug the coast of Honduras over the next few days, but exactly where that stall happens is critical in determining if it becomes a hurricane or not. Either way, it’s going to deliver a massive flooding threat to Honduras. (NOAA NHC)

Tropical Depression 19: A major Honduras flood threat, less of a Florida hurricane threat

Invest 99L was given the potential tropical cyclone treatment yesterday. It’s now officially Tropical Depression 19, and it is expected to become Sara by later today. The track of 19 is pretty straightforward — but also immensely important and sensitive to exactly where it sets up. If we look at the forecast for hour 60, which is for Saturday morning, notice that the models are in pretty solid agreement. Each dot below shows where one of the 51 ensemble members is placing Sara’s center at that time.

There is good model agreement on roughly where Sara will be over the next 3 to 4 days. But the proximity to land is going to throw an enormous wrench into determining the exact intensity. (Tomer Burg)

For Honduras, unfortunately this only means the difference between a really bad situation and a really, really bad situation. Significant flash flooding and mudslides courtesy of torrential rain will be likely heading into the next several days as 19/Sara crawls along the coast of Honduras.

Rain totals could exceed 20 inches (500 mm) in parts of coastal Honduras over the next 5 to 6 days, leading to severe flooding. (NOAA WPC)

If the center of Sara stays offshore, it could become a hurricane, which would yield an even worse outcome. But even if that does not happen and Sara stays along the coast or just inland, the rain issues will be just as bad.

But that position of Sara over the next 3 or 4 days will have implications on what happens next for Belize, the Yucatan, and Florida. Sara should eventually get dislodged from its stall and start tracking toward Belize and the Yucatan by Monday. Obviously if it’s still over water and a hurricane, that could produce a pretty rough impact on Belize or Mexico. If it emerges from over the physical coast of Honduras, it will be less of a threat to be a hurricane.

Models have increased agreement on land interaction with Honduras keeping the storm weaker and more over land the next 5 days, but there is still uncertainty. (Tomer Burg)

If anything, trends since yesterday have drastically lowered the potential for a hurricane or major hurricane. There is simply too much land interaction with Honduras and the Yucatan or Belize. But there is a heaping amount of uncertainty still.

For Florida, this means that the threat of a significant hurricane on the west coast seems to have fallen off a good bit since yesterday. That’s good. I would continue to monitor this closely, but the trends have been friendly to you. There could still be some heavy rain and strong thunderstorms as a powerful cold front sweeps across the state next Wednesday. We’ll assess this in the coming days.

In the meantime, any interests in Honduras in particular, but also perhaps Belize or the Yucatan should monitor Sara closely. Even if it never becomes a hurricane, the flooding threat is dire for coastal Honduras. We’ll keep following this aspect of things.

Sara should soon form, a significant late season threat to Honduras in particular and something for Florida to monitor closely

Headlines

  • The Caribbean tropical wave is now Invest 99L and is likely to develop into a depression or Tropical Storm Sara in the next day or two.
  • The system will come west and then slam on the brakes near Honduras. Much of what happens next depends on how close to the coast that stall occurs.
  • A stall over or near the coast would likely lead to a weaker storm that turns north and northeast next week toward the Panhandle or Big Bend of Florida.
  • A stall offshore of Honduras would likely lead to a stronger storm or potential major hurricane risk to the west coast of Florida next week.
  • Both scenarios are likely to produce significant to potential devastating rain for portions of Honduras.
  • Interests in Florida, the Yucatan, Belize, Honduras, and Nicaragua should monitor 99L’s progress closely.

Sara likely to stir up problems

Sara (spelled without an H) is likely to develop within the next 48 hours or so from Invest 99L in the Caribbean. This morning’s satellite view shows a disorganized but otherwise pretty potent little area of thunderstorms over the Caribbean. It’s at least showing nascent signs of organization, but it appears relatively lopsided. In other words, if there is a center, it’s on the northern edge of all the thunderstorms.

Thunderstorms associated with Invest 99L lie primarily to the south of where the center would likely form, so while robust it’s still fairly disorganized. (Weathernerds.org)

Over the next 48 hours, models are in good agreement that this will be slow to develop initially while moving west at a pretty steady clip. Once it gets near the coast of Honduras, the steering currents will force 99L or Sara to slam on the brakes.

Sara/99L likely to be forced to slow to a crawl or stall near the northeast coast of Honduras on Friday. (Tropical Tidbits)

This means one of two things. Either the storm will stall near land enough to not become a significant tropical system (though still a potentially major rainmaker) or the storm will stall over the Caribbean’s deep, warm water and rapidly intensify. Truthfully, neither scenario is particularly great. And in fact, modeling is in decent agreement on a major rain and flooding event potentially for Honduras. Current forecasts suggest 10 to 20 inches or more (400 to 600 mm) are possible over the next 5 days for the northern third of Honduras.

A significant rain or flooding event is becoming increasingly likely in Honduras. (Pivotal Weather)

So, regardless of how much 99L or Sara develops through the weekend, this is going to deliver abundant rainfall to at least Honduras. Belize and Nicaragua should also monitor this closely in case things should change.

Models are in great agreement on this unfortunately with almost all the European ensemble’s 51 individual members showing low pressure stuck near the coast of Honduras through 96 hours. Again, in terms of how strong this gets, where that “stuck” point happens is critical, and that’s where the bulk of the uncertainty lies right now.

Among the 51 European ensemble members, there are virtually no outliers right now in terms of getting 99L or Sara stuck near Honduras late this week and weekend. (Weathernerds.org)

From here, almost everything will depend on where that stall occurs. At a high level, we know that Sara/99L is going to get picked up and carried north and then northeast by an autumn cold front that sweeps across the Gulf next week. So for folks in Texas and Louisiana, no worries with this. But for folks in Florida, this is very important. A storm that stalls offshore to the east and north of the Honduras coast and is allowed to intensify will likely turn north and northeast farther north and east, posing a potential major hurricane risk to the west coast of Florida. A storm that stalls near or on the coast of Honduras would not be as intense and would likely either get absorbed into the front next week or come north as a tropical storm into the Panhandle or Big Bend region of Florida. Much more manageable.

Two general scenarios exist for 99L/Sara, one which is stronger and farther south, bringing a major hurricane risk to Florida next week or a much weaker farther north one. (Weathernerds.org)

Unfortunately, it’s too soon to say which scenario is more likely. The timing is a little sketchy as well, but we’re probably looking at impacts to Florida, in whatever form Sara will be in around Tuesday or Wednesday next week.

Bottom line: Folks on the west coast of Florida must again remain vigilant for another storm unfortunately. Despite the calendar saying that it’s mid-November, the weather pattern thinks that it’s mid-October. You should also be viewing this way and start considering some preparations in Florida. If you have friends or family in Honduras, ensure that they’re aware of what’s coming. Central America flooding events can be utterly disastrous. This has that potential unfortunately.

Caribbean system becoming likely in a few days, with initial significant impacts possible in Central America

Headlines

  • Tropical development is likely in the western Caribbean later this week or weekend.
  • Potential exists for some higher end development initially with heavy rainfall a threat in Central America.
  • From here, a several day ramble across the southwest Caribbean, a track northeast through the Antilles, or an eventually track north and northeast toward Florida are all possibilities.
  • Interests in Central America, specifically Honduras, Belize, and Nicaragua, as well as in Cuba, the Greater Antilles, and Florida should monitor this system going forward.

Next storm up could be problematic

The next name on the tropical storm list is Sara, and we may see that one by the weekend. I will warn you right out of the gate that this system, assuming it develops, will have a fairly high ceiling in the first few days, and there are model solutions that eventually bring it north toward Florida. It is far, far too early to speculate on exactly what this will ultimately do, but unfortunately if you live on the west coast of Florida you should be monitoring future updates on this.

Right now, the system is still just a tropical wave. I would suspect this gets Invest status later today or tomorrow morning.

Disorganized thunderstorms associated with a tropical wave in the central Caribbean are likely to become the next system in a few days. (Weathernerds.org)

The environment over the next couple days as this area comes west will be fairly pristine for tropical development. With an abnormally strong ridge of high pressure over the Eastern U.S., this will promote generally low wind shear. A weak trough of low pressure in the upper atmosphere will erode that ridge, but it will be too soon to “pick up” this tropical wave and carry it away to the northeast. The ridge should rebuild itself and at least for the first several days of its life cycle, whatever becomes of this wave is likely to meander around the western Caribbean.

The question will become if the trough off the East Coast becomes strong enough to pick up the Caribbean wave and carry it out to sea. (Tropical Tidbits)

Once that little trough, or what we call a “short wave” merges with a stronger trough off the East Coast (blue at the end of the loop above), the question will become whether or not its strong enough to “capture” the Caribbean system and force it northeast away from Central America and into the Atlantic. Odds of this happening don’t seem terribly high, but we should know in a couple days if this is a realistic possibility.

If that doesn’t happen, then we are probably looking at some potentially serious problems in the southwest Caribbean, either via a strengthening storm and/or a significant rainfall event for Honduras, Nicaragua, or Belize.

Ocean heat content in the Caribbean is near 2023’s record high levels for mid-November, indicating that there will be plenty of fuel for organization, despite what the calendar says. (Brian McNoldy)

The sea-surface temperature environment in the western Caribbean is potent for November, near 2023’s record and well above normal for even September. In other words, there will be plenty of fuel available for development.

If there’s a negative for development, it may be the amount of dry air available over the Gulf. By the time we get to this weekend, a substantial push of drier air in the wake of a cold front will infiltrate almost the entire Gulf of Mexico. If this system can close itself off and insulate against the dry air, it’s not a problem. But much like Rafael, if left at all exposed, it could eventually just get choked off from moisture allowing it to essentially self-destruct. There’s a wide variation in potential outcomes here.

Dry air may act to inhibit some strengthening of the next system by the time we get to the weekend or next week. (Tropical Tidbits)

So how could Florida be at risk? If this gets left behind and just festers in the western Caribbean, it could eventually get drawn north next week, which could pose a threat to the Florida coast. That’s a week or more away, so no one can really speak confidently on this topic. But it would be wise to continue monitoring the situation with this storm in the coming days.

So bottom line? A system is likely to develop later this week. There are many plausible options for development, but one thing is certain: There will likely be very good conditions for development in the early days late this week. From there, a meandering rain producer in Central America, a quick exit northeast across the Antilles, or an eventually track north and northeast into Florida are all plausible options on the table right now. We will continue to watch things.

With Rafael out of the picture, a new disturbance may pose a threat to the southwest Caribbean or Central America

Headlines

  • Rafael (mostly) did what it was supposed to do in the Gulf, although it’s unclear if there was a “winner” among the models.
  • A tropical wave has an increasing potential to develop in the Caribbean later this week.
  • This system may pose a threat to Central America either through development into a storm or through a slow-moving heavy rainmaker.
  • It bears close watching between the Yucatan and Nicaragua.

Rafael’s demise

Mostly as expected, Rafael succumbed to wind shear and dry air over the Gulf of Mexico this weekend. Just to tie a ribbon on this whole thing, remember, model guidance was sort of split on taking Rafael southward into the Bay of Campeche or north into Louisiana. The majority of guidance shifted toward the Bay of Campeche track late last week, and the official forecasts all generally pointed toward that happening. Interestingly, when you look at the initialization of the models since Friday, you can see the mid-level signature of Rafael kind of shear apart with some going north and some going south.

The mid-level vorticity (or “spin”) over the Gulf of Mexico associated with Rafael basically got stretched and torn apart, with some going north and some staying put or going south. (Tropical Tidbits)

That said, there was likely some element of Rafael’s moisture that got picked up by a cold front in the Deep South this weekend. Heavy rain and flooding occurred in Louisiana, especially between Alexandria and Lake Charles, with radar estimates in excess of 12 inches since Friday morning.

Much of southwestern and central Louisiana into southwest Mississippi saw as much as 4 to 6 inches of rain with 10 to 12 inches or more between Alexandria and Lake Charles. (NOAA NSSL MRMS)

Heavy rainfall in excess of 4 inches also occurred in eastern Louisiana and even southwest Mississippi. All in all, it was a substantial autumn rain event, perhaps aided a little by Rafael.

Potential trouble brewing for Central America

With Rafael now just a remnant in the Gulf, our attention will focus back to the Caribbean, where we should see a tropical disturbance in about 4 or 5 days or less drifting into the western part of the Sea. The NHC assigns about 40 percent develop odds, and a slow moving system could cause some problems in Central America. Models are divergent on exactly where, what, and when. But in general, a system tracking toward Honduras or Nicaragua seems plausible. Upper level steering currents look to be generally weak. This means that whatever does or does not develop is likely to remain slowly moving in this area.

Potential trouble is brewing for Central America late this week or weekend. (Weathernerds.org)

This means that a couple unideal solutions are on the table right now, ranging from a potentially strengthening system to a slow-moving hefty rainmaker. Neither option usually leads to good outcomes in Central America, so unfortunately this will bear very close watching for those areas between the Yucatan and Nicaragua. For the Gulf, at least initially it appears that high pressure should exert control and effectively close off the area to anything from the Caribbean. So it is not likely to be a concern. But for folks in Central America, watch this one closely.