We’re fast approaching ten years since the last hurricane made landfall in Florida. Hurricane Wilma struck the southwestern tip of the state on October 24, 2005, and ever since then, this hurricane-prone panhandle has been incredibly lucky. That could change in the coming days if the forecasts hold true.
Long Time, No See
To say that the Sunshine State has been “lucky” really is an understatement. Hurricanes are to Florida what tornadoes are to Oklahoma and earthquakes are to California. They’re just there, an ever-present part of life that residents have to watch for and occasionally worry about on a yearly basis. The state is in such a vulnerable position that it’s kind of hard to believe that it’s been almost ten years since they last experienced a direct strike from a hurricane.
Above is a map showing the track of every hurricane between 1842 and 2015 that came within 230 miles of Sebring, Florida, which is right in the middle of the state about halfway between Tampa and Lake Okeechobee. In other words, you’re looking at the track of almost every hurricane that’s hit or threatened Florida in the last 173 years.
They’ve seen so many hurricanes since we began keeping records that it’s hard to make out the state on the map.
Now, here’s that same map showing tracks of all tropical cyclones in the area between 2006 and today. The lines are color-coded based on the strength of the cyclone along that part of its path—green indicates that the cyclone was a tropical storm, while blue indicates that it was a tropical depression.
No hurricanes! There aren’t even all that many storms. That’s good in a sense, but it’s also scary because ten years is a long time for people to forget what to do and how to act when a storm is on its way. Florida was home to about 17.7 million people back in 2005, and now the state is home to almost 20 million people, which is an increase of about two million people since the last hurricane. With all of those births, all of those job transfers, and all of those fresh starts, it’s safe to say that many (if not most) of them have never gone through a hurricane in the hurricane capital of the United States.
Tropical Storm Erika
Yesterday, I wrote a long-ish, detailed discussion about why Tropical Storm Erika could turn into a Very Big Deal or fall apart into a blob of nothingness, and why the next day or two is crucial to what the storm will do when (and if) it approaches Florida.
The long and short of it is that Erika is struggling in the face of dry air and moderate wind shear. The storm looked like it was on its last gasps yesterday afternoon, and then it had a round of robust thunderstorm activity explode to the south of its circulation late last night. That convection has boomed and ebbed in the hours since, but the bulk of what makes Erika a tropical storm is stuck to the south of its center.
Tropical cyclones need deep, intense thunderstorms to completely surround their circulation in order to organize and strengthen, and as long as Erika continues to be a hot mess as it heads toward the Leeward Islands, it’s going to have a very hard time gathering strength.
Track Is Everything
Here’s this morning’s spaghetti model plot, outlining the various tracks Erika could take according to runs of different weather models:
And here’s the same chart showing this afternoon’s run of the models:
That’s a significant change! The models will continue doing this little seesaw exercise for the next couple of days, so there will be times when some models point the storm right at Miami, and others where it goes out to sea to annoy some fish.
Assuming Tropical Storm Erika is able to pull itself together, and assuming it starts to strengthen, and assuming it doesn’t get torn apart by the terrain of the islands it crosses, this could turn into a very real concern for interests in Florida. The latest National Hurricane Center forecast shows Erika making landfall in southeastern Florida as a category one hurricane. This can and likely will change as meteorologists get a better handle on the storm and what it’s going to do, but the fact that the forecast is parked over a major metropolitan area right now is enough to force residents to stay alert.
Cone of Uncertainty
The cone of uncertainty is the historical forecast track error in tropical cyclone forecasts issued by the National Hurricane Center. Historically, the center of the cyclone will stay inside the cone of uncertainty 66% of the time. Forecasters’ error in predicting the track of storms grows with time, so the cone of uncertainty grows larger as you get out three, four, five days in the forecast period. By day five, the average track error is 240 miles, meaning that the center of previous cyclones wound up within 240 miles of the five-day forecast point about two-thirds of the time.
As of 5:00 PM, the forecast shows the center of the cyclone tracking very close to the eastern coast of Florida, but everyone from Cuba, to Jacksonville, Florida is within the cone of uncertainty that far out as of the 5:00 PM advisory. Forecasts have gotten a lot better in recent years—the cone is much smaller today than it was ten years ago—but they still have a long way to go, and a dynamic, fragile storm like this is hard to nail down so far in advance.
There’s always a chance that Erika could stay weak and fall apart over the islands, or it could blow up into a major hurricane and curve out to sea, or it could skirt south of Florida and emerge in the Gulf of Mexico, or it could curve north and make landfall somewhere else on the East Coast. Even though there’s a wide range of possibilities as to what Tropical Storm Erika could do between now and next Monday, the fact that the forecasts and models continuously put Florida in play is something that should catch the attention of anyone in the region and force them to monitor this storm as we draw closer to next week.
The storm is still four to five days away from the mainland United States. Residents have plenty of time to prepare. Start thinking about what you’ll do and where you’ll go if you have to evacuate. Start getting emergency supplies together—make sure you have enough non-perishable food, water, supplies, fuel, and cash to last you at least a week in the off-chance that the worst case scenario unfolds. Even if it turns out that the storm moves safely away from land, at least you’ll have the comfort of knowing you’re prepared for the next threat.
*A huge thanks to Jordan Tessler, who took the time to write up a formula that rounds wind speeds on hurricane maps to the nearest 5 MPH and kindly shared it with me. If you’re on Twitter, your feed will be better for following him @TerpWeather.