99L getting a little better organized as we round out July

A look at invest area 99L indicates that it is getting somewhat better organized today. A general increase in shower and thunderstorm activity can be seen in satellite imagery although it is still rather poorly organized.

For the most part, the global models are not very bullish on 99L developing much in the coming days. The GFS suggests some strengthening and it is possible that this system becomes a tropical storm as it moves towards progressively warmer water. There is still some dry air around, enough so to limit the deep convection needed to allow 99L to thrive and grow at a rapid pace.

The NHC’s intensity model, SHIPS, shows modest intensification but keeps 99L below hurricane intensity. Yesterday, that same model suggested that it would in fact become a hurricane.

The ECMWF model or Euro, shows very little in the way of strengthening as the system moves towards the Lesser Antilles.

The bottom line here is that it appears some slow development is possible as 99L tracks generally westward towards the Windward Islands. Interests there should be ready for at least an increase in shower and thunderstorm activity in the coming days. I would not be surprised to see 99L become a tropical storm but it would probably be fairly weak and not very organized. Once it moves in to the Caribbean Sea, conditions are generally not very favorable for continued development.

Elsewhere, another tropical wave is moving through the Greater Antilles islands today and will spread showers and thunderstorms across Puerto Rico, Hispaniola and eventually Cuba. None of the reliable computer models indicate that this wave will develop in the coming days. Keep in mind that tropical waves often bring periods of gusty winds and squally weather. Conditions will improve across the region by tomorrow as the wave passes on by.

Speaking of tomorrow, our app, HurricaneTrack, hits the App Store. I will have a full blog post about it and the special limited time price that we will be offering as we officially roll out version 1.0. The app will feature a daily video blog plus live weather data during hurricane and tropical storm landfalls. This version will be just the start as we plan to add more features- but that will depend on YOU to help make it a success. We will have an Android version available just as soon as possible so no worries for our Android device users, we’ve got you covered too!

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Invest area 99L forms in tropical Atlantic as conditions become more favorable

The NHC is monitoring an area of low pressure well to the south and west of the Cape Verde Islands for possible development. It appears that conditions across the region are becoming more conducive for tropical cyclone formation. The dry, dusty air seen in recent weeks has significantly decreased and water temps are just warm enough to support development.

Vertical wind shear in the tropical Atlantic

Vertical wind shear in the tropical Atlantic

Looking at some of the parameters typically associated with tropical cyclone formation, we see that vertical wind shear, the difference in wind speed and direction with height in the atmosphere, is right where it should be for this time of year. In other words, shear is not a factor. It is running at about the climatological average. This should allow for a steady growth in deep tropical thunderstorms or convection. In turn, this will allow the pressures to continue to fall as the fairly large envelope of energy gradually consolidates as it moves westward.

Vertical instability in the tropical Atlantic

Vertical instability in the tropical Atlantic

On the other hand, vertical instability, which is more or less a way of saying how stable is the atmosphere. Yet another way to put it is how difficult is it to lift the air and get the vertical motion needed to create tropical convection? Right now, vertical instability is running quite a bit below the average for the tropical Atlantic. This means that we will not see rapid development of 99L. However, this is not necessarily good news. The reason? Typically, the sooner a system develops, the more chance it has to be picked up by a weakness in the subtropical ridge and track out to sea. The later the development takes place, the farther west we usually see storms and hurricanes track. So even though vertical instability is running below normal right now, it likely only means a delay in development and should not be enough to limit it completely.

Looking at the global computer models, the GFS seems to be the most consistent with development and an eventual track through the Windward Islands. The ECMWF has basically no development from this system while the Canadian CMC model seems a little too aggressive and thus has a more northerly track over the next five to six days. It during these early stages of what is called cyclogenesis that the models will waver and not be of much use. The good news is that 99L is way out in the tropical Atlantic and we will have several days to monitor its progress.

I do think that it is a good reminder that we are entering the busy months of the hurricane season. Whether or not 99L develops, August is fast approaching and the need to be ready for what the next 90 days or so brings is critical. For the next few days, folks in the Lesser Antilles should be watching 99L closely. It has a chance to develop and at least bring inclement weather to the region. How much it develops remains to be seen. It is very early in the process and much will change over the week ahead. I’ll post regular updates here and on our Facebook and Twitter pages. Keep in mind that beginning Wednesday, August 1, you will be able to purchase our brand new HurricaneTrack app for iPhone/iPod Touch (it will work on an iPad though it is not formatted for that device per se). The app will feature an in-depth daily video blog that will keep you informed through the use of graphics and narration concerning any goings on in the tropics. I’ll have a special link and blog post on Wednesday once the app is available.

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Atlantic nice and quiet, east Pacific a little activity to watch

The Atlantic Basin is free and clear of any tropical activity this 4th of July holiday period. There are no areas of concern and none of the global computer models indicate any development over at least the next five days and probably more.

In the east Pacific, there is one area of concentrated convection well off the coast of Mexico. The NHC indicates that some slow development is possible as the system moves generally off to the WNW and farther away from land.

In other news, our iPhone/Android app is getting closer to its release. We are all very excited about it and I’ll be posting a series of blog entries detailing the various features of the app. The first will be posted tomorrow.

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