The next five days

GFS model output showing the position of what would likely be a hurricane at day five. Here we see it approaching eastern Cuba after passing east of Jamaica and very close to Haiti.

GFS model output showing the position of what would likely be a hurricane at day five. Here we see it approaching eastern Cuba after passing east of Jamaica and very close to Haiti.

The very latest from the NHC indicates that we still do not have a tropical depression or a tropical storm from invest area 97L. In other words it remains a very well organized tropical wave of low pressure. That being said, it is producing winds of 40-45 mph in some of the heavier squalls as the entire system moves off to the west at around 15 mph. The Hurricane Hunter crew is currently flying through the area to sample the wind field and we will know by later this morning whether or not this is officially a tropical storm.

On the current track, the organizing system will pass through the Windward Islands today and bring with it more squally weather which will mean tropical storm conditions in some locations. Fortunately the low did not intensify quickly and as such we are not too concerned with much more than moderate tropical storm conditions at worst. By tomorrow, winds and seas will subside across the region.

Once the wave moves in to the eastern Caribbean Sea it is almost certainly going to strengthen. Water temps are very warm and the upper levels of the atmosphere support development. Some models are more robust than others but the bottom line is that this will be on its way to becoming a hurricane with time.

The track over the next five days will be very important for several reasons. First, we could see impacts as far south as Aruba, Bonaire and Curacao as what will eventually be a tropical storm passes by. Just how close to the north coast of South America this tracks remains to be seen but it is possible that it will be close enough for an increase in wind and rain by the weekend.

By late in the weekend and in to Monday, we should see a turn to the north as the western portion of the ridge of high pressure over the Atlantic begins to erode some. This will allow the sharp turn to the north that we are seeing in the model guidance. Some people have asked me how this is possible and has it happened before? It is possible due to the fact that the high pressure area, which is more dense an air mass than the tropical cyclone, relaxes some and allows the would-be hurricane to move north with time. It’s like holding a helium balloon down with your hand – once you move your hand away, which is essentially a form of high pressure, the balloon drifts up and away.

This type of set up was seen a few times in history but perhaps the most infamous was Hazel in 1954. Its track looks similar to what the models are hinting at for this system.

Around the five day time frame, it is possible for Jamaica, Haiti and Cuba to begin feeling the effects of what is more than likely going to be a hurricane. The GFS model is slightly east of the ECWMF or Euro model. The GFS moves the system over eastern Cuba and misses Jamaica but just barely. On the other hand, the Euro takes the center across Jamaica and then in to eastern Cuba. Obviously this needs to be monitored very closely by interests all along the islands of the Caribbean.

What happens after five days is the subject of much debate. Since we can all see the long range models now thanks to access on the Internet I won’t pretend to ignore it. Yes, I see the landfall in eastern North Carolina in about nine days. I also see the Eruo model taking a much slower path with a turn back to the northwest towards Florida by days nine and ten. I caution that these are extreme time frames when it comes to any large scale weather feature let alone adding a hurricane to the mix.

I for one am glad to see people talking about the models and the potential for impacts. It shows that people are in fact aware – it has their attention. That is a positive thing. We are so distracted by everyday news of politics, local and national issues, etc. that sometimes a bull horn is what we need to get people to pay attention. Knowing that there is a possibility of a hurricane threat for your area 10 days out is enough to get people motivated to at least keep track of it. Most people do not adequately prepare as they should well ahead of a landfall. Maybe the age of social media and the ability to share long range forecasts is not such a bad thing simply because it raises much needed awareness. No one I know is actually scared of a map. If they are, they need to dig deeper and ask questions about what the map means and how it might change. Social media allows for that too; it gets people engaged and talking and that is an advantage that many people can use.

So for now, let’s see what the Hurricane Hunters find and hopefully we can begin calling this what it is destined to be: Matthew. From there, the next five days are fairly straight-forward with regards to what happens. After that, no one knows for sure but it is great to see people paying attention.

I’ll have more later today.

M. Sudduth 8:15 AM ET Sept 28

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Recon crew finds 99L not organized enough to be TD or TS yet

Visible satellite image showing a fairly disorganized tropical wave moving through the NE Caribbean Sea

Visible satellite image showing a fairly disorganized tropical wave moving through the NE Caribbean Sea

The value of the Hurricane Hunters is priceless. Their work and dedication is without equal in the weather world. Today, they proved it again with the flight in to invest area 99L. The data indicates that while the overall structure of the tropical wave has improved some, it’s not quite enough to name it a depression or a tropical storm.

Instead, we have a broad area of lower air pressure and plenty of general turning in the cloud motion. However, there is some fairly strong wind blowing over the top of the system and this is injecting dry mid-level air while also pushing any deep thunderstorms away from the weak low level center.

We can see this in the satellite image I have included here. Notice that the clouds are not symmetric in appearance but rather pushed off to the south and southeast. While there is clearly a weak circulation nearing Puerto Rico, it has yet to completely close off and become well defined. It may take another day before that happens which is generally what the models that develop this system indicate.

So for now, we still have a tropical wave but it is bringing with it strong winds and periods of heavy rain for portions of the islands of the NE Caribbean Sea. This will continue to spread WNW towards the Turks and Caicos and eventually the southeast Bahamas.

For what it’s worth, the latest GFS model run indicates once again that 99L will remain a weak system and never really impacts Florida. I do not understand why this is the solution the model is coming up with but it cannot be dismissed completely. We just don’t know – despite the insistence of the very reliable ECMWF or Euro model that this will become a hurricane and enter the Gulf of Mexico. Once I get a look at the latest output from this morning’s ECMWF run, I will post an update here, followed by a thorough discussion in my afternoon video blog. If you have our app, Hurricane Impact, be sure to check the video section later today for that update.

M. Sudduth 1pm ET Aug 24

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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

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Florida in line for impacts from tropical system

NHC indicating a high chance of development in the red area, meaning impacts for Florida early this coming week

NHC indicating a high chance of development in the red area, meaning impacts for Florida early this coming week

It looks like we are on our way to having another tropical system develop and it’s only June 5th. This time, we are looking at the southern Gulf of Mexico where a broad area of low pressure is taking shape, trying to organize enough to become a tropical depression or maybe even a tropical storm by later today.

The NHC indicates a 90% chance of this happening and the Hurricane Hunters will be flying out in to the system this afternoon for a close up look. At that point we’ll know for sure what is going on in the region just north of the Yucatan peninsula, extending in to the southern Gulf and northern Caribbean Sea.

Water temps in the area are plenty warm and it will not surprise me at all to see this get named – if so, it would be “Colin”.

Now, as I said yesterday, before folks in Florida get too nervous about all of this, let’s take a look at something very important: upper level winds. I think this is what keeps the system from becoming very strong. Looking at the latest 200mb wind forecast from the GFS computer model, we can clearly see very strong winds blowing across the top of the would-be storm at the 36 hour mark. This will likely keep the system from being very symmetrical in shape and with that, it should be rather lopsided with most of the wind and rain on the east side of the low pressure center.

GFS 200mb chart from the 6Z run showing the low pressure area at 36 hours. Notice the strong southerly to southwest winds blowing across the storm. This "shear" is not favorable for strengthening but could aid in severe weather for Florida

GFS 200mb chart from the 6Z run showing the low pressure area at 36 hours. Notice the strong southerly to southwest winds blowing across the storm. This “shear” is not favorable for strengthening but could aid in severe weather for Florida (click to enlarge)

On the other hand, there will be substantial impacts for portions of the Florida peninsula. Exactly where and to what extent remains to be seen.

Winds to tropical storm force, maybe reaching 50 mph in some locations, could be expected but it’s tough to know where right now.

Very heavy rain coming from the warm Gulf of Mexico will move in as early as tomorrow afternoon. This is the biggest impact that I see for now and could cause localized flooding. It will be important to monitor your local NWS information and news sources as this will be a dynamic, constantly evolving part of the storm. In other words, it will come down to where the heavy rain bands or squall line(s) set up. Your area could get several inches of rain, along with strong gusty winds, or very little at all. We won’t know until the system is within radar range of NWS sites along the Florida west coast.

Coastal flooding will be a concern in typical onshore, surge prone areas of the west coast. I’ll know more about this once the NHC issues advisories and releases their storm surge and coastal flooding forecasts. I can highlight this better in my video discussion, especially tomorrow.

Severe weather as a whole could be a problem as well. With the very strong upper level wind pattern, it won’t take much to produce isolated tornadic thunderstorms along with possible strong down burst winds during the passage of the storm system. Again, there is no way to know where this might occur until we can see the storms on radar. The severe weather threat is high enough to warrant considerable concern, it’s just impossible to know precisely where and when.

Once the low moves across Florida on Tuesday, it will quickly move in to the Atlantic and could become stronger as it moves out to sea. The impacts along the Atlantic side won’t be as pronounced but even up the coast from Georgia to North Carolina could see heavy rain from the storm – it all depends on the angle of its track once it emerges in to the Atlantic.

I will post a video discussion shortly to follow up on the blog post for today. As new information comes in throughout the day, I will post updates on Twitter and our Facebook page – so be sure to follow along if you’re not already. We also have an app that consolidates all of our info in to one nice package. Search Hurricane Impact in the app store or Google Play.

M. Sudduth 10:25 AM ET June 5

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TD2 over extreme southern Bay of Campeche trying to become TS Barry

Satellite image of TD2 in the Bay of Campeche

Satellite image of TD2 in the Bay of Campeche

Tropical depression two is making an attempt at becoming a tropical storm before finally moving inland over Mexico within the next 24 hours. However, time is running out and the depression is not extremely well organized which should limit its potential for strengthening.

A Hurricane Hunter crew is en route to check the depression later this afternoon and their on-site info will give forecasters a much closer look at the structure as well as the winds in the system.

Whether or not it becomes TS Barry, the main impact will be heavy rain and some increase in winds and seas in the region. Fortunately, there is simply not much water to work with and this will limit any significant strengthening prior to landfall.

Elsewhere in the Atlantic, a vigorous tropical wave is passing through the Lesser Antilles and towards Puerto Rico and vicinity. This wave will bring showers, a few thunderstorms and locally gusty winds as it moves through. None of the global model guidance develops this wave as conditions are not favorable right now.

In the east Pacific, all is quiet here but I suspect that within the next week or so we will see an increase in activity here as a more favorable upward motion pattern begins to set in. I’ll discuss this in more detail in tomorrow’s blog post.

M. Sudduth

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