Know the Hurricane Cone- What it Really Means
The NHC Calls it the Cone of UN-Certainty
You should know what the hurricane cone, or "Cone of Uncertainty," as the National Hurricane Center sometimes calls it, means if you live where you live in hurricane country. You'd be surprised how many people don't!
I can't count the number of times I've heard someone say, "We're not in the cone, so we're safe." Oh really??? Soeone making such a statement does NOT understand what this part of the hurricane forecast tells us at all.
If your area is not in the cone, you can still be affected by a tropical weather system.
Let's have a look at what the cone really DOES mean, and how you should use it to know when to be prepared for hurricane season, and a possible assult by severe tropical weather.
It's called the "Cone of Uncertainty."
There is hardly ever 100% certainty
about where the center will go.
This is not an official weather site. I am not a meteorologist. My family has lived in 'hurricane country' for over a century. It's been our natural inclination to educate ourselves on tropical weather threats. This page is intended to encourage others to do the same.
They Call It the Cone of Uncertainty
"Have you put up your hurricane shutters yet?"
"Oh, no. We're not even in the cone. The edge of the cone is a good 50 or 75 miles from us."
That's part of an actual conversation I had once with a Florida resident when a hurricane was approaching.
He obviously thought the Cone of Uncertainty was inappropriately titled - that if he wasn't in the cone, the storm CERTAINLY wasn't coming his way. YIKES!
First of all, the NHC didn't misname the cone. it's called the Cone of UNcertainty for a reason. It's continually adjusted as the storm moves, and even the experts at the NHC don't know with absolutely certainty which way it will move next. The only certainty is that it bears watching.
And Secondly... well, read on for more about what the Cone of Uncertainty really indicates.
Do You Have a NOAA Weather Radio? - We consider our Weather Band Radio Indespensible in a Weather Emergency
A NOAA Weather Band Radio isn't just any old radio. It's specifically made for emergencies, and picks up a special signal from the National Weather Service that normal radios do not. It can be set to wake you with an alarm when the NWS declares an emergency alert.
If you live in hurricane (or tornado) country, an emergency weather band radio is not a luxury, it's a necessity.
We have a Midland NOAA Radio and have been very satisified with it.
I can recomment this brand from personal experience.
The Cone Forecasts the Path of the CENTER of the Storm
The cone shows the possible path of the center of the Tropical Weather System
Tropical systems have a defined center, which is called an "eye" when certain criteria are met.
In this picture, you can see the small center. It appears almost like a little dip or hole in the middle of the big swirl that is the storm. The forecast path shows where THAT little part of the storm might go. Tha's what is shown by the cone. NOT areas that might be affected by the whole storm.
The width of the cone includes a built in margin of error. And, centers are wont to "wobble." The actual center is forecast to move forward within the cone. It could go right down the middle, or ride one side.
See how big the rest of the storm is in comparison to the small center? That's typical, by the way!
See the example of Hurricane Irene, below
The Cone vs. The Storm
Example: Irene of Hurricane Season 2011
LEFT IMAGE- The state of South Carolina is basically OUT of the cone drawn on 8/25, with the track showing the hurricane will be off shore on the 27th..
RIGHT IMAGE- Nearly the entire state IS receiving severe weather on the 27th, as seen on this IR satellite image.
Was the 'cone' wrong? No. The cone was right.
You can plainly see the center of the storm well off shore, as the cone indicated it would be. That's what the cone is all about - the center. The storm is simply BIGGER than that center point:
That morning, a hurricane hunter aircraft flew into the eye of the storm, and reported that:
- Hurricane force winds exended out 90 miles from the center
- Tropical Storm force winds extended out 290 miles from the center.
That's a potential 580 mile over-all width! (assuming symmetry)
At that point, the 'cone' was perhaps 160 miles wide off South Carolina's coast, by my (very) rough estimate.
The cone is wider at five days than at two, since the margin of error increases with time
The Tropical Wind Probabilities Chart
This Chart is another useful tool from the National Hurricane Center. I use it a lot.
I like to consult this graphic when there is an active storm. It's called a Wind Speed Probabilities chart, and it can be animated.
There's a wind speed chart for 34 kt, 50kt, and 64 kt, with color coded percentage areas.
They are available on the National Hurricane Center site whenever a tropical cyclone is active. (The designation of tropical cyclone includes everything from tropical depressions to category 5 hurricanes.)
Do you see how this graphic might be less open to misinterpretation than the one called the Cone of Uncertainty?
Be Sure Your Hurricane Supplies are Ready!
Get ready ahead of time.
When a storm is heading full bore for your home is not the time to start thinking about getting ready. That's best done when there isn't even a hint of anything tropical heading your way.
You could be witihout power for days after the storm. How will you recharge your essential devices? Here's how!
Please don't think it's a good idea to have a candle or two stashed away for emergency lighting. They don't gift off a lot of light, and flames are subject to being blown out... or worse!
A storm's forecast path and cone can change from advisory to advisory as new data comes available.
The Forecast for a Hurricane or Tropical Storm can Change
The Cone of Uncertainty Can and Probably Will Shift
By way of illustration of how drastically the cone of uncertainty can change over a short period of time, here, again is an example from Hurricane Irene of the 2011 Hurricane Season.
LEFT IMAGE: The cone on the morning of 08/22/11 has the hurricane projected to make landfall very near my home on Florida's east coast in a matter of days. Note that almost all of Florida, about half of the state of Georgia, and a little corner of Alabama, are all in the five day cone.
RIGHT IMAGE: A day later. The states of Florida and Georgia are completely out of the cone.
As it ended up, Irene passed by our coast with the center about 225 miles out to sea. We got some very squally weather and pretty rough surf, producing some beach erosion.
of Helpful Hurricane Season Supplies
The following are links to product reviews of several things that I own. You might find some of them useful during hurricane seaon, either for your emergency kit, or just to have on hand.
Battery Organizer and Tester - Review
This simple, inexpensive battery organizer case with a tester is one of the best purchases I ever made! Like many people who live on the coast, I have a who...
Weather Alert Radio
Floods, severe thunder storms, tropical storms, hurricanes, wildfires, tornadoes. Some disasters strike with little warning, while with others, you may know ...
Freeze Dried Fruit - A Good Sugar Free Snack
This week, we discovered Brothers All Natural Fruit Crisps - a healthy freeze dried snack food with no sugar added. It's our first experience with freeze dri...
Back in the Cone Again - by Rodney Hotrod Parker
Here's an entertaining little song about the hurricane cone.
The Hurricane Song
Get The Hurricane Song
Did you play the above video? Did you like it? .
You can own it now! Just download it from Amazon
Monitor approaching hurricanes.
They can make unexpected turns,
like Charley did in 2005!
Out of the Cone but NOT Out of the Woods
it's amazing that so many people - even those who live in hurricane country - tend to misinterpret the National Hurricane Center's Cone of Uncertainty to mean the path of the entire storm.
Many of them seen to think that if they are "out of the cone" there is no need to make any preparations at all, because out of the cone means "out of the woods." (That's simply not true.)
Even if it looks like there is a lot of real estate between you and the nearest edge of the cone, it doesn't mean you can forget about it. Tropical cyclones can and do change directions. Sometimes those turns are accurately predicted. Other times, not so much.
People on Florida's southwest coast laerned that in 2005. Hurricane Charley was to their southwest. He had been moving northwest, and still was at 7:00 am on August 13. Within a couple of hours, he was heading north, and by 1:00 pm, he had turned northeast. An hour later, he had strengthened to a dangerous Category 4. Shortly after that, he made landfall at Port Charlotte, Florida.
It was a devastating hit, and quite a few people were unprepared.
We keep flashlights within easy reach in every room of the house during hurricane season.
It's a good idea to have a couple of roof tarps on hand, so that you can protect your home and contents from further damage right away after a storm takes part of your roof
Damabe from Hurricane Charley
Did you learn something new from this page?
More Information on Hurricanes and The Cone - (Links to Other Sites)
- Hurricane center shrinks cone of uncertainty
You won't even notice it on a map, but the National Hurricane Center's cone of uncertainty will shrink slightly in the upcoming storm season, which starts June 1.
- Hurricane Danger: Storm Surge
You may be in greater danger from storm surge than from the high winds of a hurricane.
- Hurricanes: Science and Society: National Hurricane Center Forecast Process
The National Hurricane Center (NHC) is responsible for forecasting all tropical cyclone activity in the Atlantic and Eastern Pacific basins around North America. The NHC forecasts the track, intensity, size, and structure of tropical cyclones
- FEMA's Recommended Hurricane Evacuation Kit
List of items FEMA says you should have in your evacuation kit
- What Are Cape Verde Hurricanes?
Cape Verde Hurricanes undergo initial development near the islands of the same name. Some make it across the Atlantic, some don't
If you are outside the cone,
you are NOT necessarily
out of danger!
What did you think?
Well, if you don't have any thoughts on tropical cyclone forecasting, please at least say hello!