More concerned about what Chantal may mean than what Chantal may do
Tropical storm Chantal is looking better organized this morning with very cold cloud tops and a well defined curved band on the west side of the circulation. Even though it is moving very fast to the west, it has a chance to strengthen before moving through the Lesser Antilles. Water temps are warm enough and upper level winds seem favorable to allow Chantal to become a strong tropical storm.
The impacts from the storm will be in the form of strong wind, heavy rain and rough seas. The good news is that Chantal’s fast motion will mean that these effects will be fairly short-lived. However, it is not out of the question that Chantal becomes a hurricane as indicated by some of the intensity guidance. There is not much difference in reality between 65 mph wind and 75 mph wind and people in the path of the storm need to be ready for these impacts as Chantal rapidly approaches over the next couple of days.
The forecast track is fairly straight forward with a WNW heading, bringing the storm through the Lesser Antilles some time tomorrow. After that point, Chantal will move through the eastern Caribbean Sea and then likely affect Hispaniola and Cuba. If the storm does not weaken too much by that time due to increasing upper level winds, it should turn northwest and in to the Bahamas, well east of Florida. How much land interaction there is and just how strong the upper level winds become will help to shape the future of Chantal beyond the five day forecast time frame. The official forecast shows considerable weakening and it’s possible that Chantal will fade away to a remnant low somewhere over the Bahamas. It is interesting to note that the NHC mentions that the 3-5 day intensity forecast is not one of high confidence right now.
In the long run, I believe that Chantal is important because of what its existence may mean in terms of the rest of the hurricane season. It is rare to get tropical storms to form in this part of the Atlantic this early in the season. More often than not, such development in what is called the MDR or Main Development Region indicates that the peak months of August, September and October will be substantially busier than average. Why is this? Consider what it takes to get a tropical storm to form in the first place. You need warm water temps, a moist mid-level environment, light winds in the upper levels of the atmosphere, sufficient spin or vorticity and a pre-existing weather feature to set things off, in this case, a strong tropical wave was the trigger. All of this has to come together and maintain for a tropical storm to form. It usually takes until late August for conditions to become this ripe in the deep tropics. This is why the curve of the hurricane season activity spikes as hard as it does towards the end of August and through September. When we have development in early July that mimics what we normally see in late August, that is a glaring signal, to me at least, that we are in for a very busy season indeed.
In fact, Chantal is likely just the start of things to come this month. There are indications in some of the long range models that we will see yet another strong tropical wave try to develop in about a week in the same region as Chantal. Part of this is due to the very favorable conditions we are seeing for the season as a whole and part is due to the current MJO pulse that supports upward motion in the tropics. I have mentioned this in previous blog posts as being a factor for July and here we are seeing the results of that now. I think it will be a busier than average July with at least one more development out in the deep tropics before the month is over. This should serve as a wake-up call for coastal residents all around the Atlantic Basin that this season looks like it will live up to the forecasts of being very active. If you have put off getting a hurricane plan together, perhaps this is a good time to consider putting that plan in to motion.
I am very sensitive to hype and sensational forecasts. However, when I see the likes of Chantal at this time of year during a season that was forecast to be very busy, it tells me, based on experience, that we are likely in for a long few months ahead. You nee to be prepared in any season but this is a sign we cannot ignore so no matter what impacts Chantal brings, I am more concerned about what lies ahead.
I’ll have more here with a blog post tonight.