Karl expected to become strong hurricane well offshore of the U.S.

Recent satellite photo showing TS Karl over the open Atlantic.

Recent satellite photo showing TS Karl over the open Atlantic.

The latest from the NHC tonight indicates that Karl has begun strengthening. The strong upper level winds and dry air are slowly giving way to more favorable conditions. This means that Karl is likely on its way to becoming a hurricane and probably a strong one.

Fortunately for the East Coast of the U.S. the steering pattern is such that Karl is almost certainly going to be turning away and back out to sea before the weekend. The only area that might see some effects is Bermuda and it’s too soon to know how close Karl will pass to the region. Obviously, interests in Bermuda should be watching the progress of Karl closely over the next few days.

I expect Karl to become a major hurricane which is higher than the official forecast right now. It looks “good” in the global model fields which tells me that it will likely be a very intense hurricane once it makes the turn and away from the U.S. and hopefully Bermuda.

A strong hurricane will do two things: boost the ACE score and send swells towards the coastal areas of parts of the western Atlantic Basin.

The ACE score doesn’t matter much to the lay person but in science, it’s important. It tells us much more about the quality of the storms and hurricanes that form. The higher the wind speed is the more ACE points a single storm or hurricane achieves. I suspect that Karl could add 20 to 30 ACE points when all is said and done. This will help to show that the 2016 hurricane season was more intense than the past few which is precisely what most forecasting entities were predicting. A bunch of weak, short-lived storms is usually a sign of a struggling weather pattern. We’ve already had a cat-3 hurricane occur with Gaston a few weeks back. Assuming Karl attains that status, it will boost the seasonal ACE quite a bit.

As for the surf community? Karl will help to give you a boost as well. I don’t know the specifics on it just yet since we need to wait and see how strong Karl actually gets but I think we’ll see a period of decent swells hitting the shores from Bermuda to Puerto Rico, the Bahamas and eventually the U.S. coastline. While this is inviting to skilled surfers, keep in mind that breaking waves have a lot of energy associated with them and weak swimmers will need to be careful. I’ll talk more about this potential hazard in the coming days as Karl strengthens.

M. Sudduth 11:05 PM ET Sept 19


Tropics going to be very busy for a while

TS Karl track map from the NHC. Click for full size.

TS Karl track map from the NHC. Click for full size.

We are past the mid-way point of the month and the climatological peak of the hurricane season. However, I do not think that means things will begin to calm down. Instead, it looks as though the Atlantic Basin will be very busy over the next few weeks.

Let’s begin with Julia. It’s interesting that the storm is even there in the first place since it was not forecast by any of the global models – yet, there it is. Ever since it was named it has defied almost every forecast that the NHC has put out on it. Fortunately Julia is far enough off the coast and is being sheared to the point where it is not much of an issue anyway. Strong upper level winds will likely keep it from wrapping the deep thunderstorms around the center. As for movement? Probably a slow drift pretty much where it now for the next couple of days. This will result in continued elevated rip currents for the Carolinas and Georgia but the rain and any wind will likely be well offshore.

Next up is a tropical disturbance with limited thunderstorm activity over the northwest Gulf of Mexico. Time is running out for this to develop much further but it could bring periods of showers and thunderstorms with locally gusty winds to Texas and Louisiana before moving inland this weekend.

My main concern right now is tropical storm Karl. It was upgraded from TD12 last night and is moving west over the tropical Atlantic. The overall area of energy with Karl is very impressive but it means that it could take some time for it to consolidate and strengthen. Dry air out ahead of it will likely slow its growth but this will allow it to track well to the west with time.

The NHC, along with several of the intensity models, indicate that Karl will eventually find itself within an environment more conducive for strengthening. Warmer sea surface temperatures along with less and less shearing wind just might allow the storm to become a hurricane later in the forecast period.

As we track Karl, we should see a notable bend to the south in a couple of days as strong high pressure builds to its north. I do not think that this southward push will be enough to make it a direct threat to the Lesser Antilles. All of the guidance suggests a path well to the north of the islands but we cannot be 100% sure just yet.

As for what happens beyond the five day time period – a lot will depend on how far west Karl has tracked and how strong the western Atlantic high pressure area is at the time. It is simply impossible to know this far out whether or not the pattern favors any impacts for the East Coast or Bermuda for that matter. We are going to have to wait and see how things pan out as we move through mid-week next week. I suspect that Karl will have a lot of people talking and speculating on where it’s headed. For now, we have ample time to watch it and let the pattern evolve. It’s peak time during hurricane season – we should be ready for anything.

After Karl moves farther west across the Atlantic, I suspect we will have another area of low pressure to move off of Africa and try to develop. The global models are in generally good agreement on this and it’s possible that we could have Karl and Lisa on the map at the same time.

I will be watching things very closely over the weekend. Check back here, or our app, for new blog posts. I’ll also post video discussions covering what to watch for with all of these systems over the next several days.

M. Sudduth 12:40 PM ET Sept 16