Sept 27: Matthew to Form Soon
Invest 97L is approaching the southern Lesser Antilles and will soon be inside the E Caribbean Sea as a named tropical cyclone. Beyond that, models continue to spray a range of solutions with anything from the Gulf of Mexico to the Gulf of Maine to an out to sea solution. With that said, North American impact is increasing slightly in confidence with extreme uncertainty as to where. At this point, about all I can say for sure it that Matthew will enter the E Caribbean and likely look to escape the Caribbean on the N side (Cuba-Hispaniola-Puerto Rico).
Matthew’s track from there is going to highly depend on the upper-level pattern moving across North America from W to E. If there is a trough with an upper-level low directly over Matthew then everything would likely be lifted out to sea (or at least staying slightly offshore). If a ridge with high pressure is directly over Matthew then he would likely be turned into the Gulf of Mexico or SE US. If the ridge/high pressure positioned itself perfectly to the N/NE of Matthew AND the upper level low swinging through the northern-central US becomes a player, then Matthew could be pulled into the US East Coast in a Sandy-like nature via extra-tropical transition and capture. All of these possibilities are still on the table and I won’t have a solid idea of which solution will verify until Matthew is in the Caribbean this weekend making his turning choice.
In the shorter-term E Cuba, Jamaica, Hispaniola, Puerto Rico and neighboring smaller island interests should be monitoring Matthew closely. Southern Lesser Antilles impacts are expected this ~Wednesday-Thursday AM as a tropical storm with impacts to the aforementioned northern Caribbean islands later this weekend as possible hurricane. The gulf coast and US East Coast will have a much better idea as to what is going to happen come Sunday night/Monday AM. At that point we can look at upper-level observations and see what model is handling it best.
In English: Matthew will form and hit the southern Lesser Antilles this ~Wednesday, likely as a tropical storm. Matthew will then strengthen in the Caribbean and make a turn to the N. He could hit the northern Caribbean islands as a hurricane this ~Sunday. After that, uncertainty is high as anything from a gulf storm to a US East Coast storm to an out to sea solution is possible. I’ll be narrowing that uncertainty down hopefully by Sunday but at least you know the full range of possibilities. Have a great day and please be safe! JC