Friday, September 8, 2017 3:23 PM

Hurricane Irma Update (Important)

Matthew Holliday

First and foremost, I want to thank each and every one of you who have provided very useful information on Firsthand Weather for those trying to evacuate. Feel free to continue using Firsthand Weather as a way to get beneficial information out to the public.

As expected, Hurricane Irma has strengthened once again and is just barely below category 5 strength with sustained winds of 155 mph. I have become increasingly concerned that some people have let their guards down due to the fact that Irma weakened some from an 185 mph hurricane. Please don’t do that. Only FOUR hurricanes have ever hit the state of Florida with sustained winds of 150 mph or greater. Two of those hurricanes were Andrew (1992) and Charley (2004), which were much smaller in size. You must keep in mind that Irma became one of the strongest hurricanes ever recorded in the Atlantic and was the strongest hurricane ever recorded outside of the Gulf of Mexico and Caribbean Sea. Try to keep that into perspective.

Hurricane Irma is actually moving due west now. Admittedly, Irma is being influenced by the Bermuda ridge a bit longer than I originally anticipated. That could be good or bad for the U.S. The bad news is that a delayed turn northward will likely result in this system tracking northward through the peninsula of Florida, instead of along the East Coast of Florida. This is one of the two scenarios that I said would likely occur; however in my last article, I said that I was leaning more towards Irma riding along the Florida East Coast and then possibly making a second landfall in Georgia or South Carolina. You should be aware that likely WON’T occur now. Unfortunately, it appears that Irma could have impacts from the west coast to the east coast of Florida and across regions in between. That’s not good news at all. Residents across the state including along the Florida Peninsula need to continue to prepare for this hurricane.

The good news about a more westward track is that the odds are greater that Irma COULD weaken due to interactions with Cuba; however, I wouldn’t bank on that. It will all come down to how quickly we see that northward turn. On the other hand, Irma is moving into even warmer waters. If this system is not negatively impacted in any way by Cuba, expect Irma to be a 145-150+ mph hurricane at landfall across southern Florida. I still don’t think Irma will come into the Gulf of Mexico from the west, as I have mentioned for several days ago. If anything, it would be worth watching to see if it briefly goes over Gulf of Mexico waters as it moves up the Florida peninsula, but I don’t anticipate Irma actually going due west into the Gulf of Mexico before making the turn northward. Of course, I will keep an eye on things.

It’s alarming to me the number of people who have let their guards down due to being removed from the projected path of Irma. DO NOT DO THAT. This is a very large storm and impacts will occur outside of the projected path, especially on the eastern side of the storm. This includes storm surge, which could become a major issue along the Georgia and Carolina coasts, depending on how quickly Irma turns northward. Residents across Georgia, the Carolinas, and even into parts of Alabama and Tennessee need to remain vigilant and watch for the latest forecast trends.

As a meteorologist and someone who has been following the weather closely for a long time now, I can almost always decipher between weather events that are going to be difficult to forecast and those that are not. Hurricane Harvey, for example, was not as challenging of a forecast. We knew that this system was going to stall, and regardless of where it actually hit along the Texas coast, we knew if we had a general idea of where it would hit, we would be able to pinpoint the general area that would receive copious amounts of rainfall. Hurricane Irma is not one of those cases and will be difficult to forecast through the extent of the event for various reasons. One of those reasons is the fact that Irma will be moving northward into Florida. The south Florida coastline pales in comparison to the length of the Texas coast. The exact timing of the turn northward is dependent on the very minute differences in strength of the Bermuda ridge. When the timing of this turn north could potentially change the forecast significantly, this makes forecasting such an event challenging to the very end, and the forecast becomes prone to larger errors. I told you this would be the case over a week ago. So as a precautionary measure, you should be preparing for a potentially significant, high-impact weather event if you’re located in Florida, and residents should be making preparations across the additional states that I mentioned, just in case those plans need to go into effect.

To conclude, I am going to continue watching Irma very closely. In a lot of ways, we’ll be doing a lot of nowcasting and short-term forecasting and will be relying pretty heavily on observations either from in-situ observations or remotely sensed observations from satellites. I’ll be sharing all of that information with you along the way. I am currently in the same boat as many of you are with trying to tell my family and friends what they should do and how they should prepare. I hope that you have found our information and forecasts to be helpful, and we will continue to provide this service as this event unfolds.