We need to change how we look at hurricane season.
Today we got the 2020 NOAA Hurricane season forecast update. The peak of the season climatologically is Sept 10th. I have already seen headlines like this, and they make me cringe!
“The 2020 Hurricane Season is predicted to be bad”
I give NOAA credit they are referring to it better as a busy season or above average and not just using the word “bad”. Below is their updates forecast for the season.
So why do I hate referring to the season as bad just based there might be an above-average number of storms? Well the Atlantic is a huge ocean and the number of storms might increase our chances of getting hit, but not necessarily. It only takes one storm for it to be bad. We really don’t care about the number of storms but more if they will impact us. The seasonal hurricane forecast of the number of storms doesn’t do that. That is why I feel like we focus too much on Hurricane Seasonal Forecasts of named storms. For a long time, I have not been a fan of all the mass exposure the seasonal forecasts get. The number of named storms is just a horrible metric of seasonal severity and intensity. The general public does not care how many storms there are in the entire Atlantic they simply care whether or not they will affect them. So 15-20 “fish” storms are irrelevant to the public if none of them impact the U.S. Especially when all the news coverage seems to be a “bad” hurricane season based on the high number of storms forecasted. The problems arise when people think something is going to happen and it doesn’t they lose their sense of being prepared.
There are countless examples of seasons where we get few storms, but 1-2 are impactful. Case in point was in 1992 when Hurricane Andrew was the 2nd most devastating storm to hit the U.S. It was just the 1st of only 6 named storms that entire season.
Then in 2010 we had 19 named storms which is the 3rd most active on record in the Atlantic. Though that year just 1 weak tropical storm made a U.S. landfall that season.
So to the public which season was worse? Andrew with a devastating impact and only 6 storms or 2010 with 19 storms and no impacts? I think the answer is pretty simple, but we continue to focus on the numbers of storms. The build-up of the seasonal forecasts by the media further highlights the problems. Often missing in the coverage is the perspective on how big the Atlantic is and how the number of storms doesn’t equal intensity or severity of impacts on the U.S. Also missing is communicating the unknowns of seasonal forecasting and how they are still not proven accurate enough to gauge how hurricanes could or will impact you.
Inflation of Named Storm Numbers:
Another issue that is arising is the inflation of the number of named storms. It’s kind of a running joke that we seem to be naming any thunderstorm that swirls for a few minutes in the Atlantic. This isn’t some grand conspiracy by the government to meet their seasonal forecasts for named storms. It’s a simple matter of us having better tools to diagnose tropical systems then we have ever had before. With the modern satellite observations & coverage tools like Scatterometers along with GPS Dropsondes, Doppler Radar, Hurricane Drones, etc. We seem to have an ever-growing bevy of tools to name a storm system. We just know more and are able to name a storm easier than in the past. We had a similar thing happen with tornadoes with the advancement in Doppler radar technology. The number of low-end tornadoes being reported to have increased tremendously. The Storm Prediction Center wisely knew there was an observational bias now and adjusts their numbers for this inflation. I think it’s time for the NHC (National Hurricane Center) to maybe think about something similar. I
I went back and looked at the 2005-2015 hurricane seasons and about 24% of all the storms that have formed in the Atlantic over that time period have had a minimum central pressure at or above 1000 mb. Remember this is the lowest pressure in the life span of the storm so many times the pressure was actually much higher.
This isn’t meant to be disparaging of the naming of any of these storms. It just seems logical that we are naming more weak storms than we have in the past due to our advancements in both observations and meteorological understanding of tropical meteorology. Though there does seem to be an uptick in the higher end storms being more intense. Likely due to the warming sea surface temperatures we are seeing throughout the Atlantic basin.
Better Metric:
I’ve always been a fan of ACE or Accumulated Cyclone Energy to gauge how a season is going. The ACE of a season is calculated by summing the squares of the estimated maximum sustained velocity of every active tropical storm (wind speed 35 knots (65 km/h) or higher), at six-hour intervals. (Yeah Math) It’s really a measure of how strong each storm is and how long it sticks around. Here’s a look at how ACE matches up over the past several seasons globally?
More focus on impacts and not labels:
As we saw with Matthew and Florence locally and in the past with Sandy people get caught up in what we call things and if it has a name. When in reality the impact of a storms are far more important to what we call it or it’s named. We already have this issue with wind damage where we argue over the tornado or straight-line winds when all that matters is the wind speed and damage done. Like with Matthew a storm that technically never made landfall in the Carolinas. Yet it caused $1.5 Billion dollars in damage and killed 26 people in North Carolina alone. We should spend less time on the naming of a storm or it’s the exact path and more on its impacts. The impacts to you and I are really the only way we can measure whether a hurricane season was bad or good. That fact isn’t known until the season is over not before.
