#551 Postby Andrew92 » Sun Jul 07, 2013 10:49 pm
The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.
Chantal has formed in the Main Development Region late on July 7. Since 1960, this is now the fifth storm to be named in this part of the world. Interestingly, all of the others have been within the last 25 years: Barry in 1989, Bertha in 1996, Emily in 2005, and another Bertha in 2008. Three others were very close, with Abby in 1960 and Dennis in 2005 being forming depressions just east of there and subsequently being named upon entering the Caribbean, and another storm named Chantal in 1995 forming as a depression also just east of the Leeward Islands but becoming named north of the Virgin Islands. I will include these three with my analysis on what I think Chantal may be up to in the early goings when comparing previous storms.
Of these seven total storms I am comparing to this year’s Chantal, only Barry in 1989 and the other Chantal in 1995 did not become hurricanes. Barry quickly headed northwest into an unfavorable environment, while Chantal north rather quickly after developing and then re-curving. This other Chantal was very close to being a hurricane at one point, topping out at 70 mph. Of the remaining five to become hurricanes, only Abby did not become at least a category 3. She did briefly hit category 2 intensity in the eastern Caribbean however. As for the tracks of the hurricanes, the only one not to hit land was Bertha in 2008. All of the others passed into or through the Caribbean in some way. Abby went straight across and into Central America. Bertha hit the northern islands before making a gradual northern turn into the East Coast states. Dennis made a long northwesterly path across Cuba and into the Gulf of Mexico and then the far western Florida Panhandle. Finally, Emily took a path kind of between Abby and Dennis, making it across the Caribbean and into the Yucatan, but then into the Gulf of Mexico before hitting northern Mexico.
When looking at what Chantal is forecast to do, all of the models see this year’s Chantal reaching the Caribbean. In about four or five days though, a trough looks poised to pick Chantal up and turn it more to the north. By that point, Chantal should be near 75 degrees west as she is currently moving fairly rapidly and not forecast to slow down until then. This would put her very near Hispaniola at about this time. She is also currently forecast to top out at 65 mph in about 48 hours. However, one must look at the point where that is forecast, followed by the 72-hour point, on top of western Haiti (if the forecast were to verify point by point, no need for the cone). This actually gives her a little more time to strengthen if conditions permit. Remember, history strongly suggests Chantal has a pretty good chance of becoming a hurricane.
However, there is a big fly in the ointment that none of the other storms really had to deal with. Chantal’s cone of error includes the entire southern coast of Hispaniola, along with only a very small piece of water west of there that it could avoid, again if this totally verifies. Dennis was close to hitting that island, but stayed first south and then between there and Jamaica before pummeling Cuba, and wasn’t really hindered by that island. I guess Bertha was also somewhat close in 1996, and that was one of the first storms I ever tracked as kid so I could be off base, but I seem to recall forecasts always indicating that storm would pass north of the island. Nonetheless, it is actually as she passed north of that island where she became a category 3 hurricane, albeit very briefly.
But since no storms that formed in early July actually passed over Hispaniola, it makes my prediction for Chantal’s intensity a whole lot trickier. Obviously she will weaken if she passes over the island, and I think with that cone it is too dangerous to predict that she will miss Hispaniola. However, she will have over 48 hours from now to reach that island, and possibly as much as 72. Abby almost immediately became a hurricane (though I believe the HURDAT data for that storm is suspect for now), Bertha and Emily each took about 72 hours, and Dennis took 48 hours. Therefore, if history is our guide, Chantal should have just enough time to become a hurricane if conditions are favorable enough. The first NHC discussion mentions “favorable environmental conditions” that would allow Chantal to intensify a little. The discussion doesn’t go into a lot of detail but shear does seem to be light enough in her path. There is some SAL just to her north but it currently is not affecting her and with no shear it may be difficult for it to do more than slow any strengthening that will occur.
Therefore, my current thinking on Chantal based on what is going on and what history suggests, is this: I believe Chantal will steadily intensify while tracking west-northwest, reaching the Lesser Antilles on Tuesday morning as a 50-60 mph tropical storm. Chantal will reach Hispaniola sometime on Wednesday, likely in the afternoon or evening and making landfall very near the Barahona Peninsula in the middle southern part of that island. By then, Chantal will have been over water for a little over 60 hours, and will either come just short of being a hurricane, or become one briefly with winds of about 70-80 mph. Chantal will weaken quite a bit over that island and then pass over eastern Cuba on Thursday, and will likely be a weak tropical storm with winds of 40-45 mph after spending a little over 24 hours going from landfall in Hispaniola to emerging north of Cuba. All of the islands should therefore be prepared for a tropical storm and maybe even a hurricane to come their way until Wednesday.
It is too soon to tell if Chantal will be an East Coast threat, especially if she is in such a weakened state. But one must remember that the Gulf Stream can cause storms to spin up quickly, even this time of year. One thing I have not mentioned is that Bertha in 1996 was barely clinging to hurricane intensity about 24 hours prior to landfall, but was nearly stationary over the Gulf Stream. Conditions became more favorable and she rapidly went from a fledgling hurricane to an intensifying category 2 hurricane. Such could easily be the case with Chantal if conditions are favorable enough. Do not be alarmed if you live there right now, just be watchful and make preliminary preparations, just in case. If you prepare somewhat by getting supplies and it becomes clear she won't hit you, except for food and water you can save it for the next storm that threatens.
-Andrew92
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