Track vs Intensity: plenty of uncertainties with Isaias

As you know, Isaias became a hurricane overnight despite its interactions with the rugged terrain of Hispaniola. Fortunately, we have not seen a period of rapid intensification commence which is reasonable considering how close the hurricane is to the large islands of the Caribbean.

The morning satellite imagery reveals a fairly well organized system but nothing that indicates any signs of major strengthening in the short term.

Overall, the intensity guidance is not overly dramatic which is good to see. We are at the very end of July and not late August or September when climatology tends to help things out a lot. In other words, we usually do not see intense hurricanes in this part of the Atlantic this early in the season. That being said, one never knows how these things play out and even though it looks like Isaias won't become very strong today, doesn't mean it can't at some point.

The track forecast is still fairly straight forward but minor adjustments will mean everything when it comes to impacts.

We know the hurricane will move through the Bahamas today; that much is a given. How close to Florida it gets remains to be seen. Some of the very latest guidance suggests a very close call for south Florida later tomorrow. Now, before we worry too much about this, remember that, so far, it does not appear that Isaias will be very strong which means we can deal with this - the impacts will not be severe. As long as there are no surprises with intensity, a landfall in south Florida would bring some strong winds, coastal storm surge issues and very heavy rain but again, this is manageable compared to a major, well developed hurricane. 

As for areas farther up the coast of the Southeast? It seems like the Carolinas are almost a shoe-in to receive a landfall - most likely North Carolina. But again, how strong? It is really tough to say. Water temps are about as warm as I have seen for this time of year but strong upper level winds may be enough to keep the intensity in check. The one issue I see is storm surge since a landfall along areas such as Brunswick county, with the track coming in from the south, could produce several feet of storm surge. We will know more about this over the next couple of days and will have plenty of time to react as needed.

My biggest concern is the fact that this is all happening over the weekend. Millions of people will be visiting area beaches from Florida to the Carolinas. Many will not be paying much attention to updates - they are on vacation. High surf will be an issue and rip currents are deadly - there will be a lot of people in the water and this could be a big problem.

The headache comes if Isaias intensifies beyond "manageable". If it were to ramp up and become a category two or higher, then we have some big problems ahead. All of these people at the beach will need to evacuate (hopefully just go back home). But this will need to be done quickly - and won't know Isaias is rapidly intensifying until it actually begins to do so. This is the part of hurricane intensity forecasting that has very little skill. Even a 12-18 hour window of ideal conditions is all that is needed for a bad situation to unfold. We simply cannot predict this with any degree of certainty.

So for now, those of us who are "in the know" and who live along the coast of the potentially affected areas, we just need to be ready. No need to panic and let this stress us out too much - for the moment, it does not look too menacing but that is not to say we should ignore what's coming. We have the benefit of constant satellite updates as well as coastal radar and aerial recon. If Isaias begins to show signs of rapid strengthening, we will be on top of it and can react accordingly.

I'll be posting a full video discussion this afternoon after the morning guidance has run and we see what the structure looks like as the hurricane pulls away from the Greater Antilles and into the southeast Bahamas.

Note: here is a link to our own interactive tracking map. It is a new project and we are hoping to add layers to it in the coming days and weeks but for now, check it out. You can zoom in and mouse over the plots to get more info.

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