Sandy likely to become a hurricane as it nears Jamaica

I have a feeling that Sandy is going to be a lot stronger than forecast. Why not? Intensity predictions are where there is the least amount of skill when it comes to tropical cyclones. Sandy is currently situated over some of the warmest, highest heat content water in the Atlantic Basin with an obvious building area of high pressure in the upper levels of the atmosphere. This should lead to a period of quick strengthening and people in Jamaica better be ready for the potential of hurricane conditions over the next couple of days.

Not much has changed today in the future track concerns for Sandy. It looks as though eastern Cuba and then the central Bahamas will take a direct hit from the storm (hurricane?) with plenty of heavy rain spreading across a good portion of the Greater Antilles.

What the models seem to all indicate is that Sandy will continue to strengthen once over the extreme southwest Atlantic Ocean in about three days. Here too water temps are very warm and undisturbed this hurricane season. As with Jamaica, I am concerned about portions of the Bahamas having to deal with an intensifying hurricane sitting on top of the area. Keep in mind too that Sandy is not forecast to move very fast, this will only prolong the effects in any given area.

Now, for the part where folks along the U.S. East Coast have to pay attention. The long range models are split in to two distinct camps. The GFS and its related modeling ejects Sandy out in to the Atlantic on a northeast track, easily staying away from the U.S. coastline.

On the other end of the spectrum, the two non-U.S. generated models, the ECMWF and the Environment Canada CMC models both show Sandy getting stuck in the pattern, trying to turn out but then hooking back northwest to north with a landfall along the Northeast coast. What is most concerning, but almost certainly overdone, is the absurd intensity that the models are suggesting. It is my sincere hope that there is just something not right with what the Euro and Canadian predict for the long range. If they are even close to being correct, Sandy could transition in to one heck of a hybrid mix the likes of which the region has not seen in almost a generation.

As I mentioned earlier today, even though there is a lot of interest in what happens a week from now, we need to be sure to stay focused on what may be a hurricane threat in and coming out of the Caribbean Sea. We’ll have loads of time to see how the steering pattern evolves once Sandy gets in to the Bahamas.

I would also like to mention that I believe we will see some strong winds, out of the east and northeast, for portions of the Florida east coast in the coming days. This will lead to an increase in rough surf and possible dangerous rip currents. And, if Sandy tracks closer to the coast than forecast, it is possible that tropical storm conditions could be felt in some areas of extreme SE Florida. This is a very complex situation and one that will end up affecting people across a large geographic swath.

I’ll have more here tomorrow morning including a new video blog posted to our iPhone app. I will also be watching closely to see how far west Sandy tracks and if it warrants a field mission to coastal Florida later in the week. I think the next 48 hours will tell a lot about the future for Sandy and what impacts the U.S. will feel.

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A storm for the ages? Perhaps. First, it is a Caribbean concern

99L about to become a tropical depression in the Caribbean Sea

99L about to become a tropical depression in the Caribbean Sea

There are very few instances when I have posted a headline like the one in this blog. Hype is not a tool I use to get the attention of my audience unless it is warranted and I feel it could help to save lives and property. What I am seeing in some of the global models is worthy of getting your attention and if it’s hype, then all the better in the long run.

There is a storm brewing in the Caribbean that will soon get a name: Sandy. Right now we know it as 99L, an area of investigation with potential to develop. Within the next 10 days, we may remember it as one of the great ocean storms of recent memory. Before all of that, it will be a problem for the Caribbean and that much is certain.

So far, development of 99L has been slow. It now looks as though things are coming together in the western Caribbean, a few hundred miles south of Jamaica. Water temps are as warm as could be and upper level winds are becoming more and more favorable. The NHC gives the area an 90% chance of becoming a tropical cyclone within 48 hours. I think it’s as good as done at this point and we’ll soon have TS Sandy to track.

72 hour ECMWF showing "Sandy" over Jamaica

72 hour ECMWF showing "Sandy" over Jamaica

People with interests in Jamaica need to be watching this system closely. It will bring periods of heavy rain and an increase in wind as it moves slowly towards the northeast with time. This slow forward motion is going to be a problem as the tropical rains will have a lot of time to fall over the same area for a couple of days or more. I would also not be surprised to see this become a hurricane before it reaches Jamaica. Intensity prediction is very poor even in this day of high-end computer models. Hopefully we’re only talking about a weak tropical storm in a few days but remember that hope is not a good planning tool. Being prepared is far better.

After Jamaica, the threat shifts to Cuba, Hispaniola and the Bahamas. Here too, the main issue will be excessive rain from what is surely to be “Sandy” by mid to late week. How strong it is depends on how quickly it can develop a solid inner core. Interests in the region should be paying close attention to what happens as this feature grows. We are not talking about an “in and out” system that gets kicked in to the Atlantic in a day or so. I think the big story will be the heavy rain even if this does become a hurricane in the Caribbean.

It’s what happens after the Caribbean that has the potential to make this storm one that people talk about for a long, long time.

Day five of the ECMWF showing "Sandy" after moving through the Bahamas

Day five of the ECMWF showing "Sandy" after moving through the Bahamas

To put it in simple terms, some of the global models are indicating that this storm will get caught in the southwest Atlantic and grow in to a hybrid mix of a hurricane and a Nor’easter the likes we have not seen since as far back as 1991 with the “Perfect Storm”. The closest event I can recall is “Nor-Ida” in 2009 which took the tropical leftovers of hurricane Ida from the Gulf of Mexico and transitioned it in to an epic ocean storm that blasted the North Carolina coast and points north. I was in that one and will never forget it. This storm could make that one look like a day in the park.

It all seems to have begun yesterday when some of the global models began to change their track for 99L from an out to sea event to one that may affect people from Florida to Maine. The Canadian was one of the first to show it. Then the American based GFS and finally, the very reliable ECMWF or Euro. People began talking about it within the weather blogs as if sniffing out something that movies are made out. It was incredible to read what people were saying could happen if this came to pass. Surely it was a one time fluke in the models and things would return to normal a mere 12 hours later. Not so much.

The overnight run of the Canadian global model shows pretty much the same scenario as yesterday. It takes what would be Sandy and turns it in to this enormous ocean storm that would cause coastal flooding, high winds and heavy rains for a large portion of the U.S. East Coast.

Day 8 of the ECMWF which shows a powerful coastal storm impacting the Mid-Atlantic region

Day 8 of the ECMWF which shows a powerful coastal storm impacting the Mid-Atlantic region

Looking at the latest Euro run, it too continues its forecast of developing a very large and powerful storm as the tropical energy from what would be Sandy gets pulled in to a deep trough digging in. This entrainment and phasing is rare but when it happens, it can lead to very powerful hybrid storms that have both tropical and non-tropical characteristics. The Perfect Storm in 1991 was just such an example. The overnight run of the Euro is jaw-dropping, there is no other way to describe it.

On the other hand, the GFS has all but abandoned this idea and simply sheds off the energy from the tropics in to a separate ocean storm way out in the open Atlantic. The result is….nothing. No big storm once 99L/Sandy leaves the Caribbean. It is remarkable to see such vast differences in the models and goes to show how complex the situation is. We are talking about an event that is forecast by some of the models to take place more than a week away. I debated whether or not I should even discuss it since it’s so far out in time. But I figured that rational people who read my blog would understand and appreciate the heads up if this in fact comes to pass….the bad storm that is. Maybe it’s all just a fantasy by the models that show it and the only concern, albeit a very legitimate one, will be for the Caribbean and the Bahamas. If not, and this storm happens the way the Euro shows it and the GFS showed it yesterday for a time, then we will be talking about this well past the hurricane season.

For now, we wait and go with the short term which is that we see what is a developing tropical depression in the western Caribbean. The first impacts will be felt in Jamaica and eastern Cuba. From there, we will just have to see how things turn out. The next several days could be very interesting if not very important in shaping how the hurricane season comes to an end.

I’ll post another short update this evening to go over the latest on the situation in the Caribbean. I’ll also have the video blog posted to our iPhone app by early this afternoon and it will incorporate the overnight model runs as well as the early morning or 12Z model runs to compare. If you don’t have our app, you’re missing out on a great tool in the daily video blog. It brings this discussion to life with numerous graphics, satellite shots and an in-depth explanation of what’s going on in the tropics now and what’s forecast several days out.

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Major changes with models for 99L that could lead to significant impacts for East Coast

GFS depiction of tropical cyclone over eastern Cuba in 96 hours

GFS depiction of tropical cyclone over eastern Cuba in 96 hours

There is a lot to discuss regarding the future track and intensity of 99L as it could affect literally millions of people from the Caribbean to the U.S. East Coast.

First, the current situation. Right now, 99L is rather disorganized over the Caribbean Sea but is forecast by all of the global computer models to gradually organize and become a tropical cyclone within the next two or three days. It looks like Jamaica, eastern Cuba and Hispaniola could be in line for quite a bit of rain and wind by the middle of next week.

By Thursday, the GFS places a strengthening tropical cyclone over eastern Cuba with heavy rains spreading across the southeast Bahamas. Water temps in this region are still very warm and it is possible that we could be looking at a rather strong tropical storm by this point as most of the guidance suggests steady strengthening.

By late next week, most of the reliable model output suggests a track in to the northern Bahamas, not too far off the Florida east coast. This is important because there is likely to be an indirect impact to Florida because of the presence of this system and a high pressure area to its north. It appears that a fairly strong surface high will move off the Northeast coast late next week and it could do two things. First, the high pressure north, coupled with the deepening low pressure off of Florida, will create quite a strong pressure gradient. This means the winds will be quite stiff out of the northeast for a good deal of the east side of Florida. So at the very least, rough surf and rip currents are a good bet towards the end of the week for Florida.

Sea surface temps along East Coast running at least 2 degrees above normal

Sea surface temps along East Coast running at least 2 degrees above normal

The other issue is that this high could act to block what would presumably be “Sandy” from turning out to sea. In fact, both the GFS and the ECMWF show this scenario and take what looks strong enough to be a hurricane right in to the East Coast of the U.S. somewhere north of Cape Hatteras. Sea surface temperatures in this region are running a couple of degrees above normal for this time of year and have not been disturbed by a previous hurricane earlier in the season. We are going to have to watch the evolution of this pattern very carefully over the next few days. What looked like a sure bet to send “Sandy” out to sea is no longer such a home run, so to speak. This could mean that people from the Caribbean Sea to Florida and eventually the East Coast have to deal with some degree of a tropical system over the next week or so. Interests in Jamaica, Cuba, Hispaniola and the Bahamas need to watch this system closely. We’ll see how things progress and can focus more on potential U.S. impacts as we get in to next week. For now, it looks like a slow process for 99L to develop but once it does, there is potential for it to impact a lot of people over a wide geographic swath.

I’ll post more here about 99L tomorrow morning. I also will be posting regular video blogs to our iPhone app which is a great way to visually understand what I discuss here in the blog posts. If you don’t have the app, there is no better time to get it. We’ve recently added our own tracking maps and of course have the exclusive in-field weather data, live web cams and video blogs should a landfall take place.

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Rafael bringing a lot of rain to portions of the Lesser Antilles

Three day track map from the NHC showing Rafael moving through the Caribbean

Three day track map from the NHC showing Rafael moving through the Caribbean

TS Rafael is still quite weak wind-wise this morning. However, it does not lack in the rain department and plenty of it is falling across much of the island chain of the eastern Caribbean Sea. The fairly slow movement of Rafael means more heavy rains are in store for the region and as such, flash flooding could be an issue for the region, especially in areas with higher terrain.

The storm is forecast to track closer to Puerto Rico than previously thought but this is the center I am talking about. A bulk of the foul weather lies on the east side of the center and as such, this will keep most of the Leeward Islands within the nasty side of the storm even as it passes off to the northwest today and tonight.

The forecast calls for modest intensification and it is possible that Rafael could become a hurricane as many of the intensity models indicate now. Sea surface temps are plenty warm and the upper environment should favor a steady intensification process over the next three to four days. This means a likely increase in the gusty winds associated with the more intense convection that forms within the rain bands of the storm.

Once Rafael moves out of the Caribbean, it should begin to move faster and turn to the north and eventually the northeast. The track forecast takes the center quite close to Bermuda between Tuesday and Wednesday. If Rafael is a hurricane by then, obviously this would have quite an impact on the weather for the area. We can focus on this more later in the weekend as the storm progresses through the Caribbean.

Elsewhere in the Atlantic, there are no additional areas to monitor right now.

In the east Pacific, an area of low pressure well to the southwest of Mexico is likely to become a tropical depression over the next day or so as it moves steadily away from land.

I’ll post more on Rafael early this evening with a full update in our daily video blog in our iPhone app posted this afternoon.

 

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Tropics quite active as we enter second 10 day period of the month

Satellite photo showing 97L (left, near the Bahamas) and 98L (right, near the Lesser Antilles)

Satellite photo showing 97L (left, near the Bahamas) and 98L (right, near the Lesser Antilles)

There is quite a lot going on this morning with two very active systems in the Atlantic Basin. One is 97L near the Bahamas and the other, 98L nearing the Lesser Antilles.

First up- 97L. The small low pressure system has probably been a tropical depression for a few hours but it is not bothering any land areas so it does not really matter all that much. The NHC may upgrade it later this morning but the window of opportunity for it to intensify further is rapidly closing. However, the system has a vigorous and well defined low pressure area and is producing persistent convection and therefore has some time left to strengthen a little more. The big inhibitor will be very strong upper level winds that are approaching from the west. These winds will quickly disrupt the process of upward motion and shear out the low quite efficiently.

Next we have 98L which continues to get better organized as it approaches the Lesser Antilles. The main impact right now will be an increase in tropical downpours accompanied by periods of gusty winds. These conditions will spread across a good deal of the Lesser Antilles later today and through the upcoming weekend.

There is a good chance that 98L will become a tropical storm at some point over the next 72 hours or so and this could make for a rather stormy period for the islands. I do not see any solid indication that 98L will become a hurricane while passing through the region but its fairly slow movement means a prolonged period of heavy rains.

The steering pattern is such that we should see the system turn northwest and eventually north as it feels the effects of a strong trough in the western Atlantic. This is very common for this time of year and should easily turn what ever develops away from the Bahamas and Florida by early next week.

The remainder of the Atlantic and Caribbean are quiet with no additional areas of interest noted this morning.

In the east Pacific, there is a disturbance well to the south of Mexico that has potential for development as it moves westward and away from land.

I’ll have more on the two Atlantic features this afternoon with a complete video blog analysis posted to our iPhone app early this afternoon.

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