People are just realizing they’ve been reading the cone of uncertainty on the weather map wrong with deadly results
PEOPLE have realized that they've been reading a graph used in hurricane forecast graphics wrong, which could be a deadly misinterpretation.
This week, the National Hurricane Center responded to controversy over the "cone of uncertainty" that rose from a misreading of the forecast graphic when Hurricane Ian touched down in Florida.
As specialists tried to pin down Ian's exact destination when the hurricane started to close in on Florida, the hurricane center's forecast track graphic fluctuated along the coast of the state.
The center of the cone sat over the city of Tampa Bay for days but, before it hit land, the storm moved south, on barrier islands off the Lee County coast.
From what citizens could see, the islands were never in the middle of the cone, but experts say some residents and officials overlooked that they were always in or at the edge of the forecast cone.
This oversight delayed essential decision-making in areas that were critically hit while focusing on a possible Tampa landfall.
After the lack of preparation based off of what was understood from the forecast graphic led to controversy over the cone and even calls asking for a replacement, .
The hurricane pummeled the Southwest Florida coast on September 28 with a storm surge of up to 15 feet, winds up to 150 mph or more, and up to 14 inches of rain, according to .
At least 109 people died. Where Ian made landfall in Lee County, at least 54 died, including at least 32 who drowned, the publication reported.
Numerous deaths and thousands of water rescues across Florida prompted several experts to question whether it might be time to try something other than the cone.
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On Monday, Acting Director of the National Hurricane Center Jamie Rhome explained that Ian's center stayed within or on the edge of the cone throughout the entire forecast, so how can confusion about the graphic be prevented?
What is 'the cone of uncertainty'?
Rhome said what's known as the cone of uncertainty is officially called the Tropical Cyclone Track Forecast Cone.
He said that the different names that the cone has been given "are not the official name and therein lies part of the communication and interpretation challenge."
The forecast cone's purpose is to communicate the most likely track of the center of the storm, known as the eye of the hurricane.
It is made up of a series of connecting circles, one for each time frame in the forecast that, together, make a cone that's narrow at first and much wider as the forecast progresses.
Each of the cone's circles use 67percent of the center’s forecast errors over the previous five years.
This season, the resulting window is less than 39 nautical miles in any direction at 24 hours out, 67 nautical miles at 48 hours, and 100 nautical miles at 72 hours.
Rhome stated that, based on past storms, the center of a tropical cyclone moves out of the cone about a third of the time.
"The landfall location of Hurricane Ian’s center ultimately stayed within or on the edge of the cone throughout the forecast cycle," he explained.
"Ian was a particularly large system with impacts that extended well beyond the center, and hence well outside the cone."
He added that Ian approached Florida at an acute angle, meaning that "relatively small changes in the track direction meant larger-than-normal changes in the landfall location."
'The right time'
After all the scrutiny that came over the cone following Ian's landfall, Rhome said The National Hurricane Center didn't speak up until now because they were "still in the midst of hurricane season."
"It was premature, given the extreme suffering taking place in southwest Florida and the fact that our partners within emergency management were actively involved in search and rescue efforts.";
His goal, as the NHC Acting Director, "is to help the conversation take place at the right time, in the right venue and in a productive way."
NHC staff were "focused on supporting emergency operations associated with Ian," at the time the controversy arose.
They were also "contributing to the search, rescue and recovery effort — and forecasting other weather systems across the tropics," he said.
Is the cone confusing?
When asked if the cone just confuses people, Rhome said that he thinks "it’s clear that not everyone is aware of our message to focus on hazards, which usually extend well outside of the cone."
He added that NHC is "working closely with the social science community and NOAA (National Oceanic and Atmospheric Administration) researchers to address" the concern of misunderstanding the cone.
"Prior to Hurricane Ian, efforts were underway to study the cone and other aspects of hurricane risk communication, because this issue is much more complex than just the cone," Rhome said.
He revealed that NOAA-funded researchers conducted risk communication surveys for Ian.
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The NHC is "looking forward to their collective findings on public perception and understanding of risk as these storms evolved," Rhome stated.
He said that the researchers conducted surveys for storms Marco and Laura in 2020, and Henri in 2021 as well.