On the local front: All remains calm and quiet. We continue to see optimal weather to help us dry out and continue picking up the pieces after Harvey. This weather will last well into next week. Either later this weekend or on Monday, we’ll probably have to talk a bit about some potentially hotter temperatures by mid to late next week. In the meantime, the weather looks delightful for September in Texas through the weekend. Otherwise, the eyes of the weather world are focused on Irma (and also Jose, which is taking an unfortunate track near the Caribbean). Let’s start with the latest on Irma.
In the last 18 hours or so, Irma has been undergoing some internal reshuffling (in meteorology speak, an eyewall replacement cycle and probably some land interactions) that has caused its maximum wind speeds to drop a bit. It’s now a category four storm with maximum sustained winds of 155 mph. This is actually quite common for storms of Irma’s character. What’s been so uncommon about Irma has been its reluctance to see any fluctuations in intensity until just recently. So for all intents and purposes, Irma is now behaving like a typical high-end, major hurricane.
Irma is currently west of the Turks and Caicos Islands and just north of Baracoa and Guantanamo, Cuba. It continues to move north of due west and should just graze the coast of Cuba today.
Hurricane and storm surge watches and warnings have been posted for most of South Florida.
So what will Irma do from here? Eric hashed out a few possible track scenarios through this week. As of now, the odds of a Cuba brush to weaken it or a miss to the right of Florida are looking unfortunately unlikely. Most model data and an analysis of the steering currents show fairly high confidence right now in Irma turning and either hitting Miami directly or coming in just west of there. Neither of those scenarios would be good for Florida. A track just inland might weaken it faster, but it would likely cause more significant wind and surge damage in the Miami area. A track right along the east coast and up A1A would likely lead to slower weakening and more wind and surge further north up the coast.
Either way, we’re likely looking at a severe and damaging hurricane in much of the Florida Peninsula.
In terms of intensity, we will likely see Irma have some continued fluctuations, both up and down up through landfall. This means Irma will probably come ashore as a category four or five storm. Irma will be hitting extremely warm ocean water, some of the warmest it has encountered, as it turns northward toward Florida. It will also begin to experience a little more wind shear to hopefully help offset that a little as it approaches the coast. With some good fortune, and maybe a closer brush with Cuba today, Irma could come ashore as “only” a category three storm. The unfortunate reality is that there really are no “good” outcomes here, and Floridians should be ready for a very large and dangerous hurricane this weekend. Tropical storm and hurricane force winds will be likely up much of the Peninsula, along with significant coastal storm surge, particularly on the east coast of Florida.
Further up the coast, there is increased uncertainty, with Irma perhaps briefly coming back offshore before a second landfall in Georgia. That risk seems to be subsiding, but there is some uncertainty beyond day four of the forecast of exactly how Irma will track once in the Southeast.
Inland rainfall, though well short of anything we experienced here in Texas during Harvey, will be substantial. Florida, Georgia, and South Carolina should expect a widespread 5-10 inches of rainfall, and pockets of 10-15″ possible in Florida.
A quick note on a cruel storm. Hurricane Jose now has 125 mph maximum sustained winds, and it is expected to maintain that intensity over the next couple days.
Why is Jose so cruel? Its path will take it very close to a couple of the same islands that have been devastated in the wake of Hurricane Irma. Though the current forecast will keep the strongest winds in the core of the storm north of those islands, even tropical storm impacts there will add a layer of misery to clean up and relief efforts. Fortunately, Jose looks to turn north, and it should either fall apart over the open ocean or eventually slide out to sea. Still, a cruel aspect of what is turning into an unfortunately memorable hurricane season.