Here We Go Again

First off there is no immediate threat to the northern Gulf Coast from the tropics. So enjoy your long Labor Day weekend and if you are with us here in the Berwick Bay Region, be sure and check out the Louisiana Shrimp and Petroleum Festival. With the southern flow, it has been a wet start to the festival, picking up nearly 5 inches of rain here Saturday with another two days of rain predicted. But a little rain never stopped the fun of of the S&P festival!

All the while, I will be keeping an eye on Investigation 92L just now coming into the Lesser Antilles. Conditions have been pretty rough on the system as it crossed the Atlantic, including the same things we saw with what would become Hermine: Dry Saharan air and dust; along with wind shear at the upper levels. But as of this morning we had an open wave which is showing signs of circulation.

As you can see on the visual loop, what had been an elongated area of thunderstorms, is now starting to wrap up into a more concentrated system with some sort of rotation. This morning, the system was located near 15.1N 105.6W approaching the islands of Dominica and Guadeloupe in the Lesser Antilles. The pressure was near 1005 mb, 29.68 inHg, with winds sustained near 30 knots over a large region. The radius of max winds is about 120 NM and radius of circulation about 200 NM. It is not a very organized system at this time and I honestly do not expect it to do a whole lot for most of the coming week. The NHC puts chances of development into a tropical storm at 20% in 48 hours and 30% in five days. I  agree with that but for different reasons.

Just as with Hermine, this system is not going to have an easy way through the Caribbean Sea. It is going to be up against more dry air, a fair amount shear, and at times a close proximity to land. For that reason, many of the models have it just disappear over the next couple of days. Sort of like what they did with Hermine. The major models, the US GFS model and the European ECMWF model, are having a difficult time with these poorly organized systems in a hostile environment. But if you remember back to the Hermine blogs, there was one model which consistently was right on the mark. It never gave up on Hermine, kept it south of Florida rather than hitting the mainland, then was the only model to throughout target the northern Gulf Coast of Florida rather than areas near Tampa for landfall. It nailed Hermine when others could not even find her.

That model is one you will seldom hear mentioned and when it is mentioned, many do so in kind of laughing manner. It is not a billion dollar mega-model like the GFS and ECMWF, but unlike other less known global models  the CMC does not use the output of the GFS and ECMWF for its data. Rather, the Canadian CMC model uses its own data set and parameters. For some reason, it has a handle on these weak tropical system this year. There in lies the hitch. I’d like to just grab one of those “spaghetti model” images to show you the track, but this model is not often on those images we see on TV and online. I could just put up their link. But model data sights are some of the most confusing places on Earth! Best I could do was a two picture montage of the CMC for the period Sat – Tues of next week (10th – 13th):

Now do you see my concern! This model, which was right on for very similar Hermine, has the new system off the Yucatan next Saturday, right image) as a strong tropical storm (997 mb) and by Tuesday (left image) it is approaching the Louisiana coast just to our west as a 973 mb Category II hurricane. Regular readers know I harp on the fact that even the five day forecasts can be off by up to 300 miles. Often having the system heading right for you this far out means it will surely miss you.

BUT! Considering how well the CMC handled Hermine. It never wavered on making Hermine a hurricane and having landfall moved on the norther Gulf Coast. It was the only model that pointed us in the right direction. What most concerns me at this point is the consistency. Over its last five days, this model has consistently pointed this system at some part of Louisiana by late this week into the next. So we will be watching very closely over the next few days. I think we would all be happy to see the CMC wrong an the big models right on this one.

In addition, this system like Hermine will need to run through some really tough obstacle course if it is to make it to next weekend as an organized system. First, see all that reddish air ahead of the system on the water vapor loop. That is very dry Saharan air and dust. It will have a very negative impact on the system if it gets drawn into the circulation. Tropical system want nice juicy wet air, not this stuff. In addition, if you watch the motion, you see that clouds over eastern Cuba are moving southwest, while those in front of the system are being carried off to the northeast. That is a very narrow upper-level trough which will cause a great deal of shear until it sort of pinches off late week. All the while Invest 92L will be taking a track which brings it near Puerto Rico, Hispaniola, and Cuba, all of which have mountains that tend to break up the circulation. Unfortunately, the forecast track is south of and near, but not over, any of these land masses which would likely be the death knell for a weak system. But the bottom line is that the system will likely stay weak until it enters the Gulf if it makes it that far. But if we do get a Gulf system, we saw with Hermine how quickly an unnamed storm can become a growing hurricane. And this one would have longer over the warm Gulf waters before landfall.

But as I said up front, enjoy the holiday weekend. This system is a long ways off and likely not to do a whole lot of anything quickly. Hopefully, the CMC is wrong and it just gets killed by the dry air and shear. Even if it does hold together we have a week plus to watch and prepare. Either way though, it is a sign the hurricane season is heating up and for the first time in many years, the northern Gulf seems to be in play. I will be watching closely and update as needed.

Happy Labor Day!

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