Caribbean development remains possible late next week, but don’t fall for GFS “scareicane” season

Headlines

  • Model “scareicane” season is in full force, with several unlikely GFS model outcomes showing up at times lately, a common late season bias of that model.
  • But, tropical development is looking more and more possible in the western or central Caribbean late next week or weekend.
  • Thank you to our Friday featured sponsor: Red and Black Banter!

Caribbean outlook

We continue to see at least hints of tropical development in the Caribbean in the next 8 to 10 days or so. This particular system caused a bit of a kerfuffle earlier this week when the GFS operational model, notoriously poor for handling tropical systems in the extended range showed a hurricane hitting the Florida Panhandle. Like a moth to a flame, the usual suspects on social media seeking engagement bait shared it with the masses under the veneer of either informing people of a low-probability outcome or just saying “wow.”

The last 10 GFS model runs as forecast for next Sunday. (Tropical Tidbits)

In reality, if you look at the last 10 GFS model runs, you can probably pick a point somewhere between the eastern Gulf and eastern Caribbean and it has been impacted by a modeled (read: not actual) storm. Again, the GFS has a notorious bias toward overdevelopment, particularly in the Gulf during the front and back ends of hurricane season. So it would be important to note that the likelihood of any given scenario is quite low.

In reality, here’s what we do know. We do know that the models are showing strong signals for development in the western or even central Caribbean now around next weekend. Here’s the European model for next Sunday evening.

The European ensemble model’s 50 members suggest some tropical development is a possibility in the western or central Caribbean. (Weathernerds.org)

The GFS ensemble’s 30 members also show this outcome potential.

Lower pressures show up on the GFS ensemble anywhere from Cuba through the central Caribbean next Friday. (Tropical Tidbits)

So both major model ensembles have a signal now. They’re both generally in the western or even central Caribbean with said signal as well. That’s really all we have to go on at this point.

Reading between the lines on various other data, there is support for a developing system in the same are from European AI modeling as well. That said, the overall setup is one that probably supports a system meandering within the Caribbean for a few days and then lifting north and northeastward into the Bahamas or Atlantic from this area. There’s a tremendous amount of wind shear in the Gulf, and I would not expect anything to make it there at this point in time. That said, we will continue to monitor the development risks and how they evolve over the weekend. We’ll check back in on Monday with the latest.

Friday featured sponsor: Red & Black Banter

Thank you to Red & Black Banter and all our sponsors for their support of The Eyewall this season!

Red & Black Banter: “We’re real sisters with real stories about real life. And we’re not claiming to be experts about anything. So, why are we sponsoring The Eyewall?“

I love the cartoon they did for us as well.

(Red & Black Banter)

It does speak to our mission. It was just noted yesterday that Russia has been leveraging recent hurricanes as an opportunity to continue propagating disinformation online. Much of what has been done here is in the realm of politics, which for everyone’s benefit we will not get into on our site. But there has been a significant uptick in misleading and flat-out false information spreading about how these storms form, how they move, so much so that NOAA even had to address it this week. It’s so important that you have trustworthy sources of information to turn to for extreme weather, like hurricanes.

It’s not just about getting good information; it’s about preserving your own sanity. If you looked at every GFS model run between May and November, I’m not sure you wouldn’t move to Alaska by late July. We’ve said in the past that we encourage folks shopping around for different “takes” on the forecast. But importantly, just make sure they’re credible, reliable, and measured. I think we’ve proven through our work in Houston and here the last couple hurricane seasons with The Eyewall that we do just that. Hype-free and accurate is the goal, but we try to be transparent when we miss, hold ourselves accountable, and learn from each opportunity. Thanks again for our sponsors’ support this season! And thank you for trusting us!

Calmer seas take us into the end of October in the Atlantic

Headlines

  • No tropical activity is expected over the next week in the Atlantic.
  • The first days of November remain likely to be our next window for possible development in the western Caribbean, but details are sketchy.

Quiet for now

As we begin to slowly hit the final weeks of hurricane season, things are behaving relatively normally right now. We don’t have any activity expected over the next week, and that should get us to the end of October with Oscar as the last used name on the list.

Caribbean noise remains

Modeling does continue to perk up the western Caribbean beginning later next week and into the early days of November, however. A sloppy plate of spaghetti exists on the GFS ensemble through the end of its run today, with numerous ensemble members trying to develop something in that region and either keep it buried there or lift it north-northeast toward Jamaica, Cuba, or Hispaniola.

Model noise continues to open November in the Caribbean. For now, it does not appear to be U.S. bound, but interests in the western Caribbean should monitor upcoming forecasts. (Weathernerds.org)

Now, the GFS model as shown above does have a tendency to get a bit overeager on the tails of hurricane season about development in the Caribbean. A bigger surprise would be if the model showed nothing here. That being said, this has some legs via broad background support for development over the western half of the basin, as well as some other less-robust but nevertheless present model support from the European model. I’ve written a lot and been quoted a good bit in other media publications about the increasing AI model usefulness we’ve seen this year. For what it’s worth, the AIFS too shows this kind of broad outcome right now, but it is being quite aggressive in pushing a cold front into the Gulf of Mexico around this time which is likely kicking this northeast and out to sea quickly. It’s more aggressive than the GFS and Euro with the front, so that will be something to monitor.

For now, we’ll keep babysitting and come back at you with more on Friday.

How did Oscar pop out of the garbage can without anyone noticing? A look back and what we’re watching next

Headlines

  • Tropical Storm Oscar will continue to dump heavy rain on parts of Cuba and the Bahamas as it exits out to sea this week.
  • We take a look at why we wrote Invest 94L off on Friday before it became Oscar, and in our Monday morning quarterbacking, we look at hints we could have missed.
  • Conditions may become favorable for further tropical development next week in the western Caribbean; we discuss who is usually still on the hook in early November.

Tropical Storm Oscar’s route to surprising us

Oscar is still lashing parts of the southwest Atlantic with heavy rain and gusty winds today. According to Michael Lowry, Oscar was indeed the smallest known Atlantic hurricane on record. He also accurately described Oscar’s development pathway as “nightmare fuel” for forecasters, and this forecaster could not agree more. Oscar went from nothingness to probably a category 2 or even 3 microstorm over the course of hours. This has happened in the Pacific as recently as this past summer with Hurricane John. To a lesser extent, we saw Otis last season defy forecasts and go ballistic to a category 5 storm. But every so often these storms serve as a reminder that modeling is imperfect, very imperfect.

Here’s an animated loop of Invest 94L’s forecast from the GFS model last Friday morning. You can see it takes 94L/Oscar to the west over the Turks and Caicos Islands north of Hispaniola but never develops the system and has it fall it apart rather quickly.

Friday morning’s GFS model failed to capture much development risk for Oscar as it came toward the Turks and Caicos Islands and Cuba. (Tropical Tidbits)

The European model from Friday morning offered a somewhat more realistic outcome, but even it did not look foreboding at the time and probably justified somewhere between a 10 and 30 percent chance of tropical development.

The European model was more aggressive but it even fell well short of what actually happened, though doing a much better job than the GFS in reality. (Tropical Tidbits)

Still, a minimum pressure of around 986 mb was reported over the weekend from Oscar, well under the minimum of about 1003 mb shown here on the Euro. Somewhat surprisingly, the European AI model did fairly well here, or at least was somewhat similar in nature to the Euro shown above. The ICON model did not do well, which marks one of its worst forecasts of the season.

I am somewhat intrigued by the European performance though. Small storms are tough to forecast, and we’ve noted in the past that model resolution has a lot to do with this. You simply cannot capture a hurricane that is basically the size of a typical thunderstorm complex. However, there remains something of an “art” to forecasting where one can paintbrush in some accents to improve on an otherwise finished canvas. This is a situation where looking at the Euro probably would give most of us some pause at least for writing something off. Perhaps that’s something I should have noticed more back on Friday. There are whispers of 2007’s Hurricane Humberto in cases like this. I think it just goes to show you never to take anything for granted in the tropics. You’re constantly humbled in this world.

Oscar is a much weaker tropical storm right now, and it is expected to head out to sea as such over the next day or two. (NOAA NHC)

Anyway, Oscar will turn back away from Cuba and head out to sea over the next day or so. But it will dump extensive rainfall over Cuba and the southeast Bahamas.

Additional rains in excess of 12 inches (300 mm) are possible over Cuba, with upwards of 6 inches (150 mm) in parts of the Bahamas as Oscar exits. (NOAA WPC)

Rains in excess of a foot (300 mm) are possible for small portions of southeast Cuba and up to 150 mm in the southeast Bahamas.

Beyond Oscar: Quiet, then what?

No additional tropical development is expected across the Atlantic for the rest of this week. Typically, we would begin talking about the season shutting down around now. While November storms do happen at times, they tend to be infrequent, and on an ACE basis, hurricane season is now 90 percent over. And after this week it will be about 93 percent over. But that said, the background state of the Atlantic appears as if it is going to get more favorable for development again just as we head toward November. Where would you expect storms to form in November?

Early November climatology favors the western Caribbean and open Atlantic. (NOAA NHC)

Typically, you’d look in the open Atlantic north and east of the Caribbean or in the Caribbean, just east of Central America. The latter area is the one to watch heading into November, as numerous ensemble members are beginning to pick up on activity there. Where it goes is TBD, but the water in that area remains very, very warm, which could more than support a significant storm for portions of the western Caribbean, perhaps including Central America. These storms typically get brushed off to the north and east relatively quickly by wind shear and cold fronts, so the western Gulf is probably off the hook. The eastern Gulf should still keep an eye on things, but the Caribbean should definitely keep tabs on anything that tries to develop next week. For now it’s just speculation and model hints. We’ll keep you posted as things clear up some closer in.

Surprise, surprise with two named storms in the Atlantic today

Headlines

  • Yesterday’s invests are today’s named storms.
  • Nadine is moving inland in Central America and Mexico, producing locally heavy rainfall.
  • Oscar is a micro hurricane north of Hispaniola bringing rough conditions to the Turks and Caicos Islands and perhaps the southeastern Bahamas and parts of Cuba.

Tropical Storm Nadine

Yesterday we noted that Invest 95L had a shot to become a depression or low-end tropical storm before moving into Central America today. That is indeed what happened, as Tropical Storm Nadine formed from the mess, and it is now moving inland.

Total rainfall from Nadine should be in excess of 12 inches (300 mm) in portions of Mexico. (NOAA WPC)

Nadine is primarily a rainmaker, and flash flooding is a good bet for portions of the Yucatan, Belize, and Veracruz and Oaxaca. No further strengthening is expected.

Hurricane Oscar

The Oscar for most surprising storm of the season goes to Oscar! Not only did we get a tropical storm out of Invest 94L, we got Hurricane Oscar.

Hurricane Oscar is a tiny, tiny storm with 80 mph winds. (Weathernerds.org)

Hurricane-force winds extend out a total of 5 miles from the center, while tropical storm force winds extend out about 45 miles. Oscar could best be described as a “microcane.” Still, those winds are bearing down on the Turks and Caicos Islands and moving toward the southeastern Bahamas. Widespread tropical storm and isolated hurricane conditions are likely with this as it passes through.

Oscar is expected to drift southwest-ward into or near Cuba by Monday before turning northeast out to sea. (NOAA NHC)

Nothing about Oscar is simple. Storms this small will periodically be big misses in the model world, underscoring the value of reconnaissance flights and other observational tools. Modeling completely whiffed on this yesterday and even up to this morning. This is another post for another day, but thankfully the forecast has been updated, and it now appears we have some solid footing on Oscar for folks in the Turks and Caicos and Bahamas, as well as in Cuba. At this point, no threat to the U.S. is seen, as wind shear is too high just west of here, something that should make Oscar grouchy early next week. Interests in Cuba and the southwest Atlantic should continue monitoring Oscar’s progress.