The 5 Things You Need to Know About the 2017 Atlantic Hurricane Season Outlook
DATE: June 5, 2017
The NOAA’s Climate Prediction Center just issued its 2017 Atlantic hurricane season outlook last week. Here are the five things you need to know about the upcoming hurricane forecast.
The Short Version
NOAA is forecasting an above-normal or a near-normal season, meaning:
- 11 to 17 named storms (storms with winds in excess of 33 knots / 38 mph)
- 5 to 9 hurricanes (i.e. storms with winds greater than 64 knots / 74 mph)
- 2 to 4 major hurricanes (i.e. Category 3, 4, or 5 on the Saffir-Simpson Scale / winds in excess of 96 knots or 111 mph).
#5: Remember, It Doesn’t Tell Us Where
Of course, this only gives us an overview of predicted storm activity in the North Atlantic, it does not predict where tropical storms and hurricanes will make landfall. It does not forecast tropical storm and hurricane activity for any particular place or region in the North Atlantic basin. If it did, we would be living in the future and teleporting to work in Star Trek outfits.
#4: The Technical Stuff
Getting into the weeds, the outlook predicts a 45% chance for an above-normal hurricane season, a 35% chance of a near-normal hurricane season, and a 20% chance of a below-normal hurricane season.
NOAA’s definitions are highly technical, based on the combined duration and intensity of all named storms and hurricanes in the Atlantic basin. This measure of the total overall seasonal activity in the Atlantic Basin is as reported by the Accumulated Cyclone Energy (ACE) Index, which is a wind energy index. In addition to meeting an ACE Index threshold, an above-normal season will also meet at least two of the following three conditions:
- 13 or more named storms (38 to 73 mph winds)
- 7 or more hurricanes (winds ≥ 74 mph)
- 3 or more major hurricanes (Category 3 or higher, with winds ≥ 111 mph)
A below-normal season will either fall below a specific ACE Index threshold, or, if above that threshold, meet all three of the following conditions:
- 9 or fewer named storms (38 to 73 mph winds)
- 4 or fewer hurricanes (winds ≥ 74 mph)
- 1 or fewer major hurricanes (Category 3 or higher, with winds ≥ 111 mph)
A near-normal season is one which meets neither the criteria for an above-normal season or a below-normal season.
#3: Know the Other Predictions, Too
In addition to the NOAA report, several other respected entities have recently issued or updated forecasts. The esteemed Brits at University College London say it will be an “about average” season. The Coastal Fluid Dynamics folks at North Carolina State University also say “average.” Meanwhile the learned folks at Colorado State University say “slightly below average.”
Though none of these outlooks are identical, they all have relatively similar ranges, and all three of them predict at least 10 named storms (though one ranges from 10 to 18). They also are not too dissimilar from the NOAA outlook, though the numbers all differ slightly.
#2: Should We Panic?
No. What do all these forecasts mean for people in the Caribbean and on the U.S. Atlantic and Gulf Coasts? Not a whole lot, actually.
If one looks closely at all of these forecasts, they have a whole lot of caveats, conditions, and disclaimers attached to them. I’ve read them all (so you don’t have to) and it can be daunting to unravel the meanings. The forecast language makes it clear that they are a prediction of how “busy” the Atlantic hurricane season is going to be, but also clear that they don’t predict where or when storms will happen or where they will go.
Ironically, the climatologists behind the forecasts often say that other people get more excited about the forecasts than they do, particularly in terms of the forecast’s usefulness. They know it is educated guesswork—with a lot of science behind it—but still very uncertain about specifics because it involves unpredictable future events.
Finally, just because a season is projected to be “above-average” or “below-average” doesn’t actually mean anything in terms of effects from tropical storms and hurricanes.
As emergency managers, we shouldn’t forget the lessons of history.
2010 was predicted to be and in fact was an “above-average” year for tropical storms and hurricanes. It had 19 named storms, 12 hurricanes, and 5 major hurricanes. But, despite the fact that 2010 was a “hyperactive” Atlantic hurricane season, with a lot more storms than average, no hurricanes and only two tropical storms made landfall in the United States that year.
On the other hand, remember that 1992 was predicted to be and in fact was a “below-average” Atlantic hurricane season. It had only 6 named storms and one of the latest dates on record for the first named storm. Unfortunately, that first named storm became a Category 5 hurricane named Andrew that devastated South Florida. At the time, Hurricane Andrew was the most destructive hurricane in U.S. history, and is still ranked as the 5th costliest hurricane on record with $26.5 billion in overall damage.
#1: What Should Emergency Managers Do?
If these forecasts don’t give us specific actionable information that we can use to make plans, is there any good to be had from them? Yes, there is!
When these forecasts come out, particularly the NOAA one, the news media tends to hype them up. In this case, the media attention is good. Because of this media attention, many people along the U.S. Gulf and East Coasts pay more attention to hurricanes and preparedness (for a short time).
Local and state emergency management agencies can use this increased attention near the beginning of the Atlantic hurricane season (and again in August when the updates are made).
Use these forecasts to get more traction for your organization’s planning and preparedness messages. In the coming days, network and share successful strategies with your peers in the field about how your agency can help increase levels of preparedness in your communities.
No one wants to see another Katrina- or Andrew-level disaster happen, but we can’t stop these storms from happening. Climatologists put a lot of effort into these forecasts to ensure that they give the best possible general overview of the upcoming Atlantic hurricane season. Capitalize on the buzz around these forecasts to increase awareness of threats and hazards in your jurisdiction and help your community to increase preparedness for possible disasters.
Posted by Drew Bumbak
Executive Level Emergency Management Consultant
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