Conflicting signals in the computer models for 99L

Visibile satellite image showing 99L (left) and TS Gaston (right). Click to view full size.

Visibile satellite image showing 99L (left) and TS Gaston (right). Click to view full size.

It has been a very interesting few days when it comes to what may or may not happen with invest area 99L. As of this morning, there are still no easy answers despite the apparent better organization of the tropical wave.

The NHC is indicating a 60% chance of further development over the next five days. As of this writing, there is currently a Hurricane Hunter crew heading out to investigate the system and that will help tremendously with a better understanding of the structure and local atmospheric conditions.

What has changed somewhat in the past day is the fact that one of the best performing global models, the ECMWF, has begun developing 99L in the vicinity of the Bahamas and sends it in to Florida. Other models have followed such as the U.S. generated HWRF which did very well last season with Joaquin – once it formed. I will not worry too much about the intensity indicated by the various computer guidance but it goes without saying that the very warm water temps that lie in the path of 99L make for a concerning few days ahead.

As I mentioned, the organization of the tropical wave appears to be improving. Deep thunderstorms or convection has blossomed and managed to stick around and even expand in size as of late. This could be a sign that it will finally begin to form a low level circulation and slowly start its ramp up in intensity. The Hurricane Hunter crew will be able to observe that and relay that information to the NHC almost immediately.

Recent computer model projections for invest area 99L. The track could potentially bring heavy rain and gusty winds to portions of the NE Caribbean and the southeast Bahamas

Recent computer model projections for invest area 99L. The track could potentially bring heavy rain and gusty winds to portions of the NE Caribbean and the southeast Bahamas

With all of this being said, let’s talk about short-term impacts. As it looks now, 99L will move towards the extreme northeast Caribbean Sea later today and tomorrow. This will result in periods of squally weather for portions of the northern Leeward Islands, spreading west towards Puerto Rico and maybe Hispaniola. Heavy rain and gusty winds are to be expected with some areas receiving more than others depending on the actual track and how well organized it becomes. Flash flooding is a concern for any mountainous terrain of the Caribbean islands that the tropical wave interacts with.

Next up will be the southeast Bahamas. The same scenario holds true here – periods of heavy rain, possibly bands of it if the system goes on to develop. Winds could increase more so than we will see in the Caribbean, it all depends on how quickly 99L can form a low level center – if at all. Needless to say, interests in the Bahamas should be paying close attention to the progress of this developing weather system.

It’s what happens later in the forecast period that has a lot of people quite interested, and rightfully so. The overnight models have shown a marked trend towards the west with time once the system reaches the northern Bahamas in about 4 to 5 days.

We all know by now what tends to happen with tropical cyclones when they turn west under a strong area of high pressure anchored over the Southeast U.S. It usually does not end well. Now, there is a fine line between being informative and discussing the pattern and trying to just get people anxious over potentially nothing. With social media, it is easy to spread graphics showing cat-4 and 5 hurricanes hitting some specific locale. I will not do that unless it is part of the official forecast. Right now, we don’t even have a tropical depression and there is no guarantee that we ever will.

If I live in Florida along the east coast especially, I am just going to pay closer attention to this system and be ready to act if need be. The one major downside to this NOT being named yet is that it might not command the attention and respect that it would if it were a tropical storm, for example. On the other hand, I think enough people are aware who would normally be that they won’t be caught off guard.

It’s been a long time, over 10 years, since a hurricane of any strength has made landfall in Florida. While there is a chance that streak ends sometime within the next 10 days, it is impossible to say for certain whether or not that comes to pass. It’s the heart of hurricane season. You live in Florida. You should be prepared every year as if it’s the year for your area to be hit. Beyond that, we will have to wait and see and let nature literally take its course. The data will be plentiful with recon missions planned from here on out. That will help to get a better handle on current conditions. From there, we can plan based on what happens as things evolve. It’s usually not easy and this situation seems to be no exception.

In the mean time, if you like watching harmless hurricanes roam the ocean, then Gaston is tailor-made for you. Right now, it is a tropical storm but is forecast to become a hurricane and last for days and days out over the open Atlantic. This will add to the seasonal ACE score in a big way, likely leading the way in making 2016 the busiest season in four years – pretty much as predicted by most groups that issue such forecasts.

In the eastern Pacific, the are two well organized disturbances that are both likely to go on to become tropical storms and eventually hurricanes. The good news: both are well away from Mexico and moving generally west with no impacts to land.

I will post my daily video discussion here later this afternoon followed by another blog post late tonight. Follow along as well in our app, Hurricane Impact, for blog updates, social media and video info right on your iOS device. Search Hurricane Impact in the App Store.

M. Sudduth 10:15 AM ET Aug 23

About Mark Sudduth

Greetings! I am Mark Sudduth, the founder and editor of The site began in 1999 as a way to post info concerning tropical storms and hurricanes for any interested visitors. Little did I know how big it would become in the years since. Now, we have millions of visitors from all over the world who have come to rely on the site as a no non-sense, tell it like it is resource for all things hurricane related. We are supported by a combination of corporate sponsors and our loyal Client Services members who subscribe to premium content on our sister site, I am married with six energetic and intelligent children and live in southeast North Carolina. I graduated UNC-Wilmington in 1995 with a BA in Geography and have studied the effects of hurricanes on our society ever since.
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