Tropical Weather Discussion - August 27, 2012
Good afternoon folks!
Tropical Storm Isaac is churning across the Gulf this afternoon headed for an eventual landfall somewhere on the LA coast. Despite what appeared to be conditions favorable for intensification, Isaac has stubbornly remained a tropical storm. We won't complain. I think the single biggest reason Isaac hasn't been able to reach hurricane status has been its shear size. A storm that covers as much ocean as Isaac takes time to consolidate all that energy to the center of the storm. And Isaac is trying to do that. The central pressure has steadily dropped but it's doing so at a slow pace. The winds haven't kept pace with the pressure, remaining steadily around 40-50mph. I'll be surprised to see Isaac not at least make a minimal hurricane it will struggle to make much more than that.
The track forecast has proven to be a challenge, as anyone following this storm can attest. It hasn't surprised me to see this storm track further west than was at first expected. The real question now is how far west. The models are usually pretty accurate within the 48-72 hour point. The single most significant factor at the moment for the track forecast is the development of the high pressure ridge over the SE US. The 11am storm discussion from the hurricane center mentions the fact that this high appears to be building more than forecast. The circulation around the high could push the track further west than the current forecast is indicating.
At the moment, I think the current model solution looks reasonable but I think we can expect the track forecast to be nudged a bit further west over the course of the next two days before landfall.
Elsewhere, we should keep our eyes on the eastern Atlantic. A new wave off the African coast has caught NHCs eye and they give it a low chance of becoming a tropical system in the next 48 hours. The GFS develops this wave fairly significantly in the central and western Atlantic by the end of the week. We'll keep an eye on that system.