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Maria Finally Departs the Caribbean and Jose Fades. Whats Next?

September 22, 2017/by Steven Copertino

Good Evening

Back on Monday we highlighted the potential for Maria to become an extremely dangerous Category 4 or even 5 Hurricane before reaching the small island of Dominica in the Lesser Antilles, and unfortunately that is exactly what happened. Maria rapidly intensified into a Category 5 hurricane with 160 mph winds just before making landfall on the small island, and then preceded to head from SE to NW, leaving the entire island in its core for at least three hours. The storm was the second Category 5 land falling hurricane this season, tying the 2007 with Dean a Felix. Details are still very spotty, but the pictures, video, and first-hand accounts of Dominica are heart-breaking. Most, if not all of the homes on the island have suffered severe damage, with some houses being completely destroyed. Due to the topography of the island, devastating mud slides and land slides were common, which swept away homes, roads, and well-built concrete structures. Its hard to believe that we’d have a storm that would rival the total devastation that Hurricane Irma caused just a few weeks ago, but we could be looking at yet another situation where an entire island community has seen complete devastation. With the peak of the Cape Verde season quickly coming to a climatotlogical end, we should see the frequency of storms impacting this region begin to wind down, but I would not be surprised to see one or two more systems during the month of October given the active state that we are currently in.

Damage from Hurricane Maria when it hit the island of Dominica as a Category 5 hurricane with winds of up to 160 miles per hour (Credit: The Guardian)

Due to the high, mountainous peak of Dominica and the amount of time that Maria spent traversing the island, the inner eyewall of the storm become disrupted and fractured, but not for long. On Tuesday the storm began to rapidly regain strength after dropping to a Category 4 hurricane. Recon missions throughout the day found that the storm had an incredibly compact eye of around 5-8 nautical miles and the winds rose from 155 mph to 175 mph during the course of the day, with the pressure falling to an incredible 908 millibars, making the storm the tenth strongest on record for the Atlantic basin.

Recon also released numerous dropsonde instruments which provide a vertical profile of various locations in the storm, and some of these probes happened to measure extreme winds of around 190-195 mph at the surface, but it is not certain whether these were instantaneous gusts or actually representative of the storms strength. Regardless, the storm began to approach the US Virgin islands late in the day on Tuesday and into the evening. Very deep convection began to develop quite rapidly around the center of the storm, and before long, concentric eye walls began to develop. This marked that the storm was about to attempt an eyewall replacement cycle before hitting Puerto Rico. It was clear that the storm would have issues completing this process and then intensifying once again due to the storms intensity and the size of the outer eyewall, but it also signaled for new dangers to arise. The storms wind field grew quite substantially as it approached Puerto Rico early Wednesday morning, causing the carious weather stations to be blown apart in addition to both weather radars on the island.

The storm raged ashore with winds in the 155 mph range, making Maria a strong Category 4 hurricane on the Saffir-Simpson scale. Maria went on to produce prolific flooding, wind damage, and cut a path of carnage across the island that would send all of its inhabitants into darkness as all of the power facilities went down during the storm. Details are also still rolling in slowly on the extent of the damage to the island, but it may be safe to say that the Puerto Rico that existed before Maria is no longer there. Estimates say that power may not be restored to some portions of the island for possibly up to 4-6 months. Additionally, much of the infrastructure will need to be rebuilt, which will be a daunting task in of itself. The next few weeks and months may be quite rough for the locals, but with resilience and endurance the people of the island will be able to overcome this disaster and restore their home to levels greater than before Maria.

GOES 16 imagery of Hurricane Maria making landfall on the island of Puerto Rico with winds of up to 155 miles per hour

Maria has since left the Caribbean, and land interaction along with an increase in vertical wind shear have been affecting the system. The storm weakened down to a Category 2 on Thursday, but has since regained some strength and is now a 125 mph Category 3 hurricane. The storm is currently located very close to the Turks and Caicos, producing winds up to tropical storm force on the islands along with torrential rainfall as it slowly heads NNW at around nine miles per hour. Maria should keep this heading over the weekend and into the early portion of next week, but some key aspects of this forecast remain in question. While it is quite likely Maria misses the United States, the American model has been trending strong with the riding out ahead of Maria in the past few runs, bringing the storm precariously close to the Outer Banks of North Carolina. Again, such a solution looks unlikely right now, but with the remnants of Jose still meandering around, we truly will not know just how close the storm passes to the east coast before it makes its famed passage out to sea.

Trend loop of the GFS model showing the westward trend over the past 5 runs (Courtesy of TropicalTidbits)

So What Else?

Well, we have the remnants of tropical storm Jose which has finally become post-tropical after 70 advisories by the National Hurricane Center. For reference, this storm has been ongoing since Hurricane Irma was north of Hispaniola! The remnants of this storm should gradually dissipate over the next few days and really should not be much of a threat besides increased wave action and showers. Elsewhere, Tropical Storm Lee has come back to life after shedding about three different low level circulations over the past three days and is located well out in the open Atlantic, just east of a large upper level low. Lee is an extraordinarily small system and is reminiscent of Hurricane Michael from 2012 in that of it is relying heavily on baroclinic process to form convection and strengthen. Given its size and the upper level conditions, I would give the storm a higher than normal odds of becoming a small hurricane over the next few days.

Lastly, our eyes turn to the western Caribbean as the month of September begins to fade. Medium and long range models are showing that this area of the Atlantic basin may become much more active during the next few weeks as a large area of upper level divergence sets up right over extremely warm sea surface temperatures of around 31-32 Celsius. This upper level divergence over very warm waters would promote a large amount of deep convection to form, which could eventually lower pressures in the Caribbean and cause a tropical system to form. This is all at least 8-12 days out at this point, but the signals are there that we should begin to monitor this region for potential tropical cyclone development as we near the beginning of October.

I will have a full update on Maria and any other threat that may pop up on Monday!

ECMWF model showing large scale rising over the western Caribbean in about 10 days. Conditions could become quite favorable for tropical cyclone genesis by this time.

Have an excellent weekend!

Steven Copertino

Hurricane Irma Eyes Down Florida, Jose and Katia Become Life-Threatening Hurricanes

September 8, 2017/1 Comment/by Steven Copertino

Good Evening

Since our last update, the Atlantic has racked up more records that it would take too much time to list all of them here. There have been some major changes with our storms, and unfortunately they are not welcome changes. To help get the word out about these potentially catastrophic hurricanes, we have temporarily removed our paywall. We hope everyone stays safe over the next few days during these exceptionally dangerous times.

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Starting off with the most imminent threat to land, we have Hurricane Katia, which is nearing the coast of Veracruz in Mexico. Katia has steadily organized into a hurricane with winds of 105 miles per hour, and recon will be heading into the storm shortly to get a better understanding of the storms strength before it makes landfall later this evening and into early tomorrow morning. While Katia will pose a formidable storm surge and wind threat to the immediate coast, the main threat with the storm will be the threat for life-threatening mud slides triggered by very heavy rainfall as the storm moves inland. Though the storm is relatively small, it still could produce 8-14″ of rain across portions of Mexico, which is more than enough to cause serious issues for locals.

This afternoons HWRF model showing potential rainfall accumulations over portions of Mexico during the next few days. Life-thretening mud slides will be possible as the storm moves inland (Courtesy of NOAA HRD/HWRF)

This afternoons HWRF model showing potential rainfall accumulations over portions of Mexico during the next few days. Life-threatening mud slides will be possible as the storm moves inland (Courtesy of NOAA HRD/HWRF)

Katia will likely be very close, if not over Mexico by 1am Central time, so the time the cyclone has to strengthen is very short, but it would not be all that surprising if the current reconnaissance mission found that the storm had indeed become a major hurricane. While it has little impact on the overall threats from the storm, having three active major hurricanes would be a first for the Atlantic. Regardless, Katia should rapidly weaken tonight over the high terrain of Mexico, and should degenerate into a remnant low by tomorrow evening. Overall, people in the path of Katia should be aware of rapidly deteriorating conditions as early 8pm central.

GOES 16 IR shot of hurricane Katia nearing landfall over the Mexican coastline (NASA GHCC)

The next storm likely to affect land is Major Hurricane Jose. Since the last time we looked at Jose it was just a minimal hurricane. Since that time, Jose has put on a very impressive bout of intensification as it was able to hold onto the pocket of low shear just behind Hurricane Irma’s expansive outflow. An earlier recon mission into the storm found that winds have dramatically increased to 150 mph, making Jose an extremely dangerous Category 4 hurricane. With Jose acquiring 150mph winds, this marks the first time in Atlantic hurricane history that back to back storms have attained 150+mph winds. As of this evening, Jose looks rather healthy, despite the storm taking on a more sheared appearance from the aforementioned outflow of Irma. Another recon plane will be in the storm shortly to get an intensity sample, but it seems likely that the storm will at least maintain major hurricane status while it nears the islands.

IR loop of Major Hurricane Jose approaching the Leeward islands with 150 mph winds

Jose may come uncomfortably close to the northern Leeward islands tomorrow afternoon, the same area which Irma quite literally wiped out just a few days ago. With little infrastructure left on the islands of Barbuda and Anguilla, even sustained hurricane force winds will cause massive issues for those left on the islands. This afternoons model guidance took the storm just north of the islands, which would spare them the tight core of the storm, which is good news, but the islands may still experience very heavy squalls, intense wave action, and occasional gusts to hurricane force during the day tomorrow. As I write this, it seems that the storm is really starting to show signs of weakening a bit as the cloud tops begin to warm and the system quickly becoming lopsided, despite the eye remaining quite visible. We will have to see if this trend continues, as this would lead to the storm possibly weakening quite a bit by the time it reaches the islands, which would be very welcome news.

After the storm moves north of the islands, the eventual track of the hurricane becomes very uncertain. As Irma eventually makes landfall somewhere along the Florida peninsula, it will begin to reshape the steering currents over the western Atlantic. This could cause the storm to begin to head east and just south of Bermuda by the middle of next week. At that point, another ridge of high pressure may try to build in overhead and cause the storm to track in an erratic fashion. For this reason, we will still have to keep a weary eye on Jose over the next week or so.

This evenings HWRF model showing winds from Jose coming dangerously close to the islands devastated by Hurricane Irma

Once again, we move onto Hurricane Irma

Irma has gone through a lengthy eyewall replacement cycle over the past day, which has allowed for the storm to weaken from its 185 mph intensity down to a 155 mph Category 4. Irma is still a very powerful hurricane, and those who think that just because the storm has weakened over the past day or so means that it will be less impactful in the long run is severely mistaken. In fact, there is some data that would suggest that the storm has begun to re-intensify just north of the Cuban coast-potentially back to Category 5 levels. This will have to be confirmed by the NHC in the coming hours.

Over the past 24 hours, the majority of the global models and their ensembles have shifted west, away from SE Florida, and now have SW Florida, and then the western coast in the direct path of this system. Additionally, radar observations show that it is almost certain that the center of Irma will make landfall on the Cuban coastline later tonight. This is a huge change from prior forecasts, and just how long the storm stays over Cuba will determine just how much the storm will weaken. As of this time it seems like Irma will make landfall on the Cuban coast early Saturday morning and could remain over land until later in the day tomorrow. Afterwards, the storm would likely be exiting into a region of extreme oceanic heat content and favorable upper level conditions. Most of the high resolution models, including the new “Deep Thunder” IBM model has Irma rapidly intensifying once it leaves the Cuban coast. I am hesitant to say that Irma will be able to intensify quickly as soon as it leaves the coast due to the fact that this is a very large storm with a very large core, and it may take some time to reorganize, depending on how much damage is done. It is however, likely to at least regain some strength, possibly back to a high-end Category 4 as it nears Florida.

Current GOES 16 shot of Hurricane Irma with 155 mph winds just off the Cuban coast

With regards to the track of Irma, it now seems likely that Miami will not get the brunt of the storm. Areas in SW Florida, including the Florida Keys may see the full extent of Irma on Sunday, with extremely damaging winds, deadly storm surge, and flash flooding. The models have been shifting west all day, and we may very well see more shifts this evening, but the chances are drastically increasing that the west coast of Florida will experience the worst of the storm. Those in the path will have to monitor Irma very closely over the next few days, and stay tuned for further updates as new data become available. We will have more on this developing situation tomorrow for the public.

****When making decisions, always consult the National Hurricane Center, your local National Weather Service, government officials, and local Emergency Managers.****

Latest storm-specific model tracks for Irma, showing a considerable shift away from SE FL (Courtesy of weatherbell)

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Have a great evening!

Steve Copertino