August 20, 2020

Here's What You Need To Know About The Impending Peak Of Hurricane Season


We're coming up on the peak of hurricane season. It feels like we've already passed that point since we've seen so many named storms this year, but we don't hit the climatological peak of the season until the second week in September. It's important to use this time as an opportunity to prepare for what forecasters expect will be an active couple of months. 

1) What We've Seen


This hurricane season is off to a record start. An average year would only have seen the 3rd or 4th named storm by this point in August. This year, though, we'd seen 11 named storms by August 14th, and there's plenty more to come.

The map above shows what we've seen in the Atlantic so far this year. The season started with Tropical Storm Arthur off the coast of Florida in the middle of May, making this the sixth year in a row we've seen the first named storm form before the "official" start of the season on June 1.

This year rivals 2005 in terms of the raw number of named storms that have formed by this point. Even though we're off to a faster pace than the awful season 15 years ago, this year's storms so far don't hold a candle to the early-season storms of 2005 (think: Dennis and Emily). With the exception of Hurricane Isaias, most of the storms we've seen this year were relatively weak and short lived. Don't take too much solace in that fact, though. It only takes one bad storm hitting land to make a "mundane" season tragic.

2) What's Could Come Next

Sea surface temperature anomalies (°C) during the week of August 15, 2020. Source: NHC

Forecasters recently updated their seasonal outlooks to bump up the seasonal numbers to include the storms we've already seen this year. In short, they're still expecting an active season on top of what we've already seen; the A through K storms this season were the appetizer before the main course.

NOAA's updated outlook, issued August 6 calls for a total of 19-25 named storms this year, including many hurricanes and a handful of those hurricanes strengthening into major hurricanes (category three or higher). Colorado State University's revised outlook from August 5 falls along the same lines, calling for a total of 24 named storms by the end of the season.

Some of the favorable conditions include:

➤ Warm sea surface temperatures across the Atlantic basin. The thunderstorms that drive hurricanes derive their energy from warm sea surface water. The warmer the water, the greater the opportunity for organization and strengthening. Warmer waters also allow sea surface temperatures to rebound quicker after a storm passes by, affording subsequent storms more energy to work with if they pass over the same area.

➤ We're heading into a period that could see one disturbance after another roll off the western coast of Africa, increasing the odds that at least a few of them will develop.

➤ The eastern Pacific Ocean has ENSO-Neutral conditions right now and the region could head into a La Niña as we move into the fall. La Niña, or abnormally cool waters in the eastern Pacific, cut down on thunderstorms and tropical cyclones in that part of the world, which lessens the destructive wind shear that can flow east toward the Caribbean and Atlantic and shred apart any disturbances trying to develop. 

A seasonal outlook is a general guide. This year's forecasts are like blinking red lights hanging over the Atlantic Ocean, giving folks in harm's way a heads-up that conditions are very favorable for lots of storms to develop over the next couple of months. Even though we've already had 11 named storms so far, we've still got more than 80 percent of the season left to get through and it could be very active. 

3) We Might Run Out Of Names

Astute weather enthusiasts will note that, if the high end of those outlooks comes to pass, we could run out of names before we run out of storms. We all love a good process story (and how!), so here's a refresher on how it works if we run out of storm names.

The Atlantic Ocean has six lists of names that are reused every six years. 2020's list was last used in 2014 and (minus any retirements) it'll be used again in 2026. The lists exclude names beginning with the letters Q, U, X, Y, and Z for lack of suitable replacements, leaving us with 21 names to roll through each year.

If (or when) we reach the last name on this year's list—Wilfred—any named storms that form after that will be named using Greek letters. The hyperactive 2005 hurricane season is the only year we've ever exhausted the list of names; 27 storms formed that season, with the last six named using the Greek alphabet.

The Greek alphabet goes: Alpha, Beta, Gamma, Delta, Epsilon, Zeta, Eta, Theta, Iota, Kappa, Lambda, Mu, Nu, Xi, Omicron, Pi, Rho, Sigma, Tau, Upsilon, Phi, Chi, Psi, and Omega.

We got through Tropical Storm Zeta in 2005, which formed on December 30 that year and continued through January 6, 2006. If a storm forms after midnight on January 1, it would count toward the 2021 hurricane season and we'd start using that year's list of names.

If you're wondering, there's no set procedure to retire a Greek letter—the consensus seems to be we'd either skip the letter or just keep using it—nor is there a Plan C in case we exhaust that alphabet as well. However, if we have 46 named storms in one year, figuring out what to call them would be the very least of our worries.

4) A Small Chance Doesn't Mean No Chance


It's common to see a low chance for development on the NHC's tropical weather outlooks. We like to brush off a low risk of anything—low risk of storms, low risk of rain, low risk of getting run over by a reindeer—but ignore any risk of tropical cyclone development at your own peril. 

We've already seen it happen once this season. On the evening of May 26, the National Hurricane Center’s tropical weather outlook gave a disturbance off the Southeast coast a 30 percent chance of developing into a tropical cyclone within the next day or so. The next morning, the disturbance quickly organized into Tropical Storm Bertha and made landfall just a few hours later. 

Not much changed impacts-wise once the disturbance organized into a tropical storm. The system was destined to bring plenty of rain and gusty winds to the Carolinas regardless of its development.

But rapid changes aren’t always so innocuous. Think about 2017’s Hurricane Harvey, which rapidly developed into a category four hurricane as it approached Texas, and Hurricane Michael one year later, which explosively developed into a scale-topping category five hurricane as it made landfall on the Florida Panhandle.

A low chance doesn’t mean no chance. Goodness knows we’ve found that out plenty of times in recent years. Things happen fast in the weather world and it’s a great fortune that we live in a time where we can track sudden changes in a storm’s organization and warn people as it happens.

If there’s a disturbance or a storm approaching land, it's important to pay attention and check in with the latest forecasts and warnings every couple of hours. Weather forecasting is still an inexact science, and storms can still catch us off guard.

5) We're Exceptionally Vulnerable This Year

We're in the midst of an uncontrolled pandemic and a tinderbox political environment. This summer more than any, the United States is uniquely vulnerable to significant disruptions as a result of a landfalling tropical system.

It's bad enough going into an active hurricane season during normal times, but any bad storm right now could tip communities over the edge into catastrophe. Whether it’s a major hurricane barreling toward the coast or a slow-moving mess that floods communities with double-digit rainfall totals, it’s going to be incumbent upon each of us as individuals and families to have a plan and know exactly what to do if your home is threatened by rising waters or high winds.

Coastal communities are doing their best (we hope, anyways) to figure out how to work evacuation shelters and emergency response plans with the coronavirus in mind. The very last thing we need during a landfalling hurricane is a coronavirus outbreak among people who are displaced from their homes, which would not only put enormous stress on the people who can’t go home (or have no home left to go back to), but it would also put unnecessary strain on local hospital systems that might be overwhelmed already.

6) Forecasts Are More Than Just A Map

There’s more than meets the eye in a hurricane forecast. The design of a hurricane forecast map is inherently misleading given the risks posed by these often-sprawling storms.

The Cone Of Uncertainty Isn’t Just For Show

The cone of uncertainty is the historical margin of error in a tropical system’s forecast path. Every year, meteorologists at the NHC verify their forecasts to see how far off their forecast points were from the actual location of the storm’s eye at each timestep in the forecast.

Historically, the center of a cyclone stays within the cone of uncertainty two-thirds of the time, venturing outside of the cone the other one-third of the time.

If you look at past forecasts compared to recent ones, you’ll notice that the cone is much smaller than it was just a couple of years ago, and it’s quite slim compared to 10 or 20 years ago.

The Cone Is Just For The Center Of The Storm

It’s important to remember that a hurricane forecast map entirely revolves around the center of the storm. Some hurricanes are 600 miles across, meaning the effects of their wind, rain, and storm surge will extend hundreds of miles from the center of the storm.

Rain, Rain, Rain

Much of the focus on a landfalling storm revolves around the wind and storm surge right at the coast, but as we’ve seen so many times in recent years, it’s the rain that can do the most damage over the widest area.

An unnamed tropical disturbance in 2016. Hurricane Harvey in 2017. Hurricane Florence in 2018. Tropical Storm Imelda in 2019. It seems like we have at least one of these horrendous flooding events every year, and the probability of these destructive inland flooding events will grow as a changing climate brings about more frequent and more prolific heavy rain events.

Track Is More Accurate Than Intensity

Hurricane forecasts have improved by leaps and bounds over the last couple of decades. Thanks to improved forecasting techniques and better modelling, hurricane track forecasts are much more accurate than they were just ten years ago.

One of the important things to remember about a tropical cyclone forecast is that, as a general rule, there's more confidence in track forecasts than intensity forecasts. Intensity forecasts are pretty darn good—we don't get too many significant surprises anymore, but storms can still take us by surprise.

Fluctuations in the intensity of a tropical cyclone often rely on subtle and fragile conditions in and around the storm. Sometimes,  modern tools and technology can miss when a storm will rapidly intensify (or rapidly fall apart). This usually isn't too much of a concern when a storm is far out to sea, but when it happens close to land—like Harvey's sudden intensification into a category four storm as it approached Texas in 2017—it can have tremendous consequences for folks in the path of the storm.

7) Easily Overlooked Prep

We all know to stock up on food and water before a hurricane hits, but as we saw with the panic shopping at the beginning of the pandemic, we’re too settled into the mindset of preparing for all disasters like blizzards. Here's what we should focus on heading into the peak of the season.

Travel Plan: The greatest physical most folks could face during a landfalling tropical cyclone is flash flooding from torrential rains. You're probably at greater risk of getting stranded by a flooded road than you are of losing your home to extreme winds or a devastating storm surge. If you live in any state that borders the coast—not just a community near the coast, but hundreds of miles inland—scope out and program into your phone alternate routes to get to work, school, the store, and home in the event that a common road near you is flooded out. Most deaths during a tropical system are the result of people drowning in freshwater flooding.

Evacuation Plan: If you live along or near the coast, start thinking now about what you'll do if you're told to evacuate. Evacuating is tough during "normal" circumstances, but it's especially difficult now that we have to stay mindful of the coronavirus. Some communities are encouraging the use of hotels or staying with family or friends to lessen the burden on community shelters.

Power Outage Plan: Landfalling tropical cyclones can generate widespread power outages long after they've weakened and traveled many hundreds of miles inland. We saw it with Isaias just a couple of weeks ago; many of the folks who lost power for a week or longer in the Northeast weren't prepared for it. It's easy to overlook the threat for power outages until the lights go out. I sound like a broken record at this point—plunking this list at the bottom of every hurricane post and even posting it in Forbes a few weeks ago—but here are some things you need to get through an extended power outage.

➤ Food: You want to focus on non-perishable food that you don’t have to cook. Fruit cups are good. Ravioli and Spaghetti-Os are good. Milk is no good. Neither is fresh meat. (Spam is great, if that’s your thing.) Have enough to last each person three meals a day for at least a few days. Assume that McDonald's won't have power, either.

➤ Water: Bottled water is fine. Bottle-it-yourself water is better on your wallet and better for the environment. Remember to bottle enough for drinking and to use for flushing the toilet and washing your hands.

➤ Light: You need batteries and flashlights. F-L-A-S-H-L-I-G-H-T-S. Not your cell phone’s flashlight feature. An actual flashlight—many, if you can swing it—along with enough batteries for a few refills each. Trust me. Relying on your cell phone’s flashlight feature during a long power outage will just drain your cell phone and leave you without communication or light, and that’s no good.

➤ Cell Phone Charging Packs: Speaking of cell phones, rechargeable battery packs are cheap enough now that they're in reach even on a budget. It's wise to invest in a good battery pack that can give your smartphone at least a few full batteries on a single charge. Even the cheaper ones they often sell near the checkout lane in Walmart are good for a quick battery boost in a pinch.

➤ Gas Up Your Car: Long gas lines are a staple of pre-hurricane coverage on the news, and for good reason. The only thing worse than being stuck at home with no power is being stuck in a powerless home because your car is running on empty. You don't want to get stranded at home (or elsewhere) without any gas. Fill up the tank before the storm hits. 

➤ Money: Your debit card and credit card aren’t going to work if the power is out and you need to go to the store and buy stuff. If you can afford a small cushion, having some physical cash on hand can get you through an extended power outage.

➤ Prescription Meds: Keep up with your prescription refills during hurricane season. If you know there’s a storm brewing and one of your prescription refills is coming due, it’s wise to refill it because you don’t know when you’ll be able to get it filled again.

[Top Image: NHC]

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I graduated from the University of South Alabama in 2014 with a degree in political science and a minor in meteorology. I ran Gawker's The Vane for two years and I've contributed to Mental Floss, Forbes, Popular Science, and the Washington Post's Capital Weather Gang. I also teamed up with Outdoor Life to write a book called The Extreme Weather Survival Manual, which came out in October 2015.

1 comment:

  1. A small to medium size generator/inverter (See the Ranier for example) is worth its weight in gold. Use non-ethanol gas. Keeps your refrigerator cold, provide some light and a fan or two, etc. You'll also need some good 10 guage extension cords.

    ReplyDelete