Summary: Ian is still forecast to rapidly intensify today. Western Cuba is bracing for a Cat 3 landfall, and Ian could be a Cat 4 by Tuesday Evening. The Florida Keys are on alert but likely to be on the fringes, no actions at the moment. The models then start to diverge, but landfall in the Big Bend or panhandle of Florida on Thursday or Friday is likely. Here’s the details …
For the latest as always check the National Hurricane Center’s Key Messages regarding Tropical Storm Ian (en Español: Mensajes Claves). Based on the 5am forecast, here is what the impact/damage swath looks like as of the 5am forecast:
The track through 60-72 hours (late Tuesday) seems pretty clear. The Cayman Islands are under a hurricane warning but should only see the fringes of the storm – how bad depends on the exact timing of the explosive intensity growth of the storm. Impacts to Cuba are likely to be in excess of $1 Billion USD based on this forecast, with over a million people in the tropical storm wind swath, with the worst of the impacts staying west of Havana. Conditions are ripe for rapid intensification: by Tuesday Ian could well be a strong Category Four (120 knots, 138 mph) hurricane.
After that things get fuzzier. Ian is expected to sneak around the edge of a decaying frontal system and start to turn northeast (as well as encounter an unfavorable environment, which should knock the intensity down). As NHC says in their 5am discussion:
With the cross-track spreading remaining between 200-220 n mi at days 4 and 5, it cannot be overstated that significant uncertainty remains in Ian's long-range prediction.
Here is what that looks like graphically using the TAOS/TC model dispersion analysis tool. Notice how the nice neat circles suddenly turn into an elongated ellipse and the range for the 120 hour forecast is from near Mobile Bay to off of Cape Canaveral:
As you can see NHC split the difference between the models, with GFS being on the left edge and the European models (UK, ECM) on the right. While a landfall in the panhandle seems most likely, we probably won’t have a good handle on this until late today or tomorrow. The exact track will make a lot of difference for evacuations, as the “target rich” environment of the Sarasota-Tampa-Clearwater region is or is not in play. Being that close to a Cat 4 storm, a small wobble will make a huge difference in impacts. Those on the west coast of Florida and panhandle need to pay close attention and be ready to implement your hurricane plans – probably starting tomorrow (Monday). So you should check this afternoon to see what’s going on, and certainly listen out regularly starting in the morning.
As for Coastal GA/SC, The Cone of Shame Cometh(*)! In other words, Coastal GA is within the NHC uncertainty cone, the zone where there is a 2/3 chance the center of the storm will pass. It hasn’t crept in to South Carolina yet but should do so today. The media often makes a lot of this, but what does it mean? in terms of impacts not a lot – you can be in the cone and not feel much, you can be out of the cone and get high winds that cause a tree fall on your house. So the cone says nothing about impacts, which is what we care about.
It’s still hard to tell what the impacts will be in this region. It’s likely that the coast, from Jacksonville to Charleston, will see high onshore winds for a day or two with conditions deteriorating Wednesday and tropical storm conditions offshore with the appropriate marine advisories. On the barrier islands that means gusty winds, rain, and a likelihood of some shallow coastal flooding at high tides. Nothing terribly dangerous is expected, but as we all know even a foot or two of extra water causes a lot of damage. How bad depends on how close and slow the storm moves by. Again, we won’t know more about that until Monday.
It wouldn’t surprise me to see school closures and other impacts for Thursday or Friday spreading across the region. Depending on the exact track, conditions inland will likely be rain and gusty winds, depending again on how far inland and how rapidly the storm decays. Right now, Thursday looks to be the worst day in the Savannah/Beaufort area, with winds 20mph gusting to 30mph and some rain squalls. Inconvenient, hazardous if you lack common sense, but not dangerous. Further south, in Brunswick conditions might flirt with tropical storm conditions, starting late Wednesday. So inconvenient (especially if power outages!), but not at this point looking at much in the way of actual damage. Again, this is all pretty uncertain; we’ll have a better picture in the morning (Monday), but that is to give you an idea of what to expect. It will be worth paying attention to local advisories for later this week to see what actions local emergency managers recommend. No need to wear out your refresh key at this point, check back in Monday morning, and Tuesday for sure start checking for what your local community is doing.
(*) Those of you with animals are probably familiar with the Elizabethan collar, aka the “Cone of Shame,” that has to be put on critters sometimes to prevent them from tearing off a bandage or licking/chewing on an injury.