Elsa Slowly Organizing as it Moves Rapidly Towards the Lesser Antilles

Hello everyone!

PTC5 became TD5 late last night and TS Elsa early this morning after it managed to close off a center of circulation and produce sustained winds over 40 mph.

The system’s fast forward motion and a little bit of dry air to its northwest has kept a lid on its ability to strengthen today, though there are preliminary signs that Elsa may be preparing to let the shear go and build an inner core.

Microwave satellite imagery that specializes in peeking under the top layer(s) of clouds in tropical cyclones shows a few hints at low-level banding near and northwest of Elsa’s center this evening. There ain’t very much meat on them bones, but you need to frame a house before you can fill it in with the stuff that looks pretty and it seems as though Elsa has checked that first step off the list today. I’ll be watching closely over the coming days to see if Elsa is able to wrap some of the intense convection currently east of the center around to the western side. If it can, strengthening would be in order.

Elsa will cross the southern Lesser Antilles briskly tomorrow, pushed northwest by a strong ridge of high pressure over the Atlantic. Residents of Grenada, St. Vincent and the Grenadines, St Lucia, Martinique, Barbados, and Dominica should be prepared for tropical storm force winds and heavy rain capable of producing flash flooding and mudslides.

There isn’t a ton of near-term track uncertainty, but that will change in a hurry tomorrow evening.

As Elsa approaches Hispaniola, interaction with land combined with a slight weakening in the Atlantic ridge will open the door for a turn more to the north. As is so often the case with westward-moving tropical cyclones, when/where exactly that north turn happens is the million dollar question.

A turn to the north a bit sooner would drag Elsa across the high peaks of Hispaniola and Cuba, likely significantly disrupting the circulation (though Isaias and Laura last year showed not all TC interaction with the islands is destructive for the TC). This is what the ECMWF model shows with Elsa potentially ceasing to exist as a tropical cyclone over the Bahamas by early next week.

Another possibility is that the ridge stays stronger for a little longer and Elsa continues more west-northwest through the Caribbean, potentially impacting Jamaica. This would give the storm more time over the warmer waters of the central/western Caribbean which would open the door for a bit more strengthening.

The GFS is currently depicting that latter solution and if it ends up panning out, Elsa may have a window to make a run at hurricane status with good upper-level outflow, little dry air in the vicinity, and warm water. Residents in Jamaica and Cuba should be preparing for this possibility even if it’s not the most likely scenario at this point.

What is the most likely scenario? When two skilled forecasters (like the GFS and ECMWF models) are offering very different prognostications, in the absence of clear evidence favoring one prediction, wise money bets on the average of the two.

Indeed, the wisest money in the tropical cyclone forecasting world, the hurricane specialists at the NHC, have drawn a forecast track almost right down the middle of the two predictions with a little hedge towards the GFS’ western track. A path like this would leave the door open for some more strengthening especially near Jamaica/Cuba, but we’d need to keep an eye on how organized Elsa can be while traversing the eastern Caribbean before having confidence in those higher-end intensity predictions.

What happens to Elsa after the Caribbean?

By Monday evening, Elsa should be somewhere in the vicinity of Cuba with the range of possible outcomes currently extending from the western Caribbean to the central Bahamas. At this point, a trough is likely to dig towards the northern Gulf and curtail the western edge of the Atlantic subtropical ridge that has been steering Elsa WNW. This means that the system is likely to turn towards the north, though again the exact timing/placement of that turn is uncertain.

Another major uncertainty is Elsa’s intensity around this time. If the core isn’t too disrupted by interaction with land, the ocean and atmospheric environments support intensification into a hurricane. However, there will be plenty of opportunity for land interaction and dissipation into a tropical wave is absolutely still on the table.

With that in mind, it’s still a bit early to be getting too concerned about Elsa in Florida, but impacts of some sort seem like a legitimate possibility based on what we know now. Any head start you get on preliminary preparations will be time well spent, even if the storm fizzles over Hispaniola. Whatever planning/preparations you can get done now will serve you well when a storm eventually does pose a serious threat whether that be next week, next month, or next year.

I’ll be back tomorrow with another update. As always, please consult official forecast sources at nhc.noaa.gov and weather.gov to guide decisionmaking. Graphics in today’s post come from tropicaltidbits, weathernerds, NESDIS, and the US Navy.

-Jack

Published by Jack Sillin

I’m a third-year atmospheric science student at Cornell University who has been blogging about the weather since 2011. While I’m not officially a meteorologist, I have accumulated a bit of experience forecasting both local weather (in western Maine and New Hampshire) as well as national/international weather during my time writing for weather.us and weathermodels.com. I also have experience programming in Python, teaching concepts in weather forecasting, and communicating forecast information to general audiences.

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