Tropical Storm Melissa Forms In Caribbean; Future Track A Toss Up

The forecast track of a tropical storm or hurricane 
usually takes the form of a "cone of uncertainty."
The future track of Tropical Storm Melissa is
SO uncertain that the cone of uncertainty is a
circle, meaning it could go anywhere. 

 
was born this morning in the central Caribbean Sea, but where this storm will eventually end up is anybody's guess.

The disturbance that grew into Melissa had been rocketing westward across the Atlantic Ocean. It was moving so fast, it couldn't really develop into analyzing. 

Now, the storm's forward speed is slowing way down, so it has been able to grow into a tropical storm. As of 11 a.m. this morning top wind speeds were 50 mph.  

The National Hurricane Center alerts the public about a predicted path of a tropical storm or hurricane with something called a cone of uncertainty. 

It's called that because the graphic looks like a cone. The middle of the cone is where the official forecast is, but areas either side of the path are shaded in to reflect the possibility the storm could go to the left or right of its predicted path. 

Forecasters usually know where a tropical system is headed over the next 12 to 24 hours so the range of predicted paths is initially small. A few days out, there's more uncertainty, so the areas on a map shaded in where the system might go is wider. Hence the cone of uncertainty. 

I bring this up because today's "cone of uncertainty" for Melissa is essentially a circle. Which basically means it could go anywhere.  It's the weirdest cone of uncertainty I can remember with any tropical storm or hurricane. 

Steering winds in the atmosphere are weakening so it's hard to say which direction Melissa might go. That said, even though steering winds are weak,  there are fairly strong winds blowing the tops of Melissa's thunderstorms askew, so the storm might not strengthen all that fast. Plus, dry air might get injested into Melissa, which would also slow a strengthening trend. 

Satellite view of Tropical Storm Melissa shows it's kind of
a mess, as strong upper level winds are screwing
up the thunderstorms that power the storm. 

Whether Melissa grows into a hurricane also depends on where it goes. If it gets stuck over land, it would weaken, or at least not really strengthen. 

On the other hand, the Caribbean waters are at record warm levels for this time of year.  If it stays over the water, there's a chance this thing could get pretty strong. 

Super warm water is jet fuel for tropical systems, so if Melissa ends up growing into a pretty good size hurricane, I wouldn't be surprised.

Since Melissa will be moving so slowly, any island it nears will get incredible boatloads of rain. 

 Big flash floods and landslides are already in the forecast though this weekend in the Dominican Republic and Haiti. 

A hurricane watch is also in effect in parts of Haiti. Jamaica is under a tropical storm watch.  

It's going to take a few days to figure out where Melissa is headed and whether it would be a threat to the United States. If it does eventually make it to the U.S., the most likely state to be hit would be Florida. But even there, the chance looks reasonably low at this point. 

Category 6 And Cones Of Uncertainty: Changes In Hurricane Forecasting Coming

With some hurricanes getting stronger under the influence
of climate change, should a new Category 6
be designated for the strongest ones?

 Category 5 hurricanes are probably the worst storm anybody could experience. 

These monsters have winds of at least 157 mph.  As the National Hurricane Center describes a Cat 5: 

"A high percentage of framed homes will be destroyed, with total roof failure and wall collapse. Fallen trees and power poles will isolate residential areas. Power outages will last for weeks to possibly months. Most of the area will be uninhabitable for weeks or months."

And that's not even talking about the monster storm surges with Category 5 hurricanes that can push tides to 20 feet higher than normal, with huge, battering waves.  

Gosh, if a Category 5 hurricane is that bad, what would a Category 6 do?

So far there's no such thing. Or is there such a thing?

Researchers suggest it might be time to create that category.

It's not close to hurricane season in the Atlantic Ocean yet. That starts June 1. But people spend all year thinking about these dangerous storms.  Which means changes could be in the works. 

So, the new hurricane category is bubbling out there. 

Category 1 through Category 4 hurricanes have a specific range of wind speeds. For example, category 3 hurricanes have winds of 111 to 129 mph.

Some hurricanes have been getting stronger in recent decades. That's all  thanks to climate change, which is making oceans and air temperatures warmer. That adds to atmospheric toasty water vapor, which is jet fuel for hurricanes. Especially when that water vapor is super warm. 

Cat 5s, have no upper wind range. Just 157 mph or more.  I would put the upper limit of Category 5 storms at about 175 mph.

Given the rising potential for stronger hurricanes, the question is should there be such a thing as a Category 6 hurricane?  We've already had a few hurricanes, or typhoons with sustained winds of 175 mph or more.

Typhoon Haiyan in 2013 had maximum sustained winds of 175 to 195 mph, depending on which meteorological agency was doing the measuring.

Hurricane Patricia had top sustained winds of about 210 mph off the west coast of Mexico in October, 2015. Patricia was a very weird hurricane, a very small in area storm that went from a nothing burger to extreme in a very short period of time, then rapidly weakening as it approach landfall. 

Hurricane Dorian in the Bahamas back in 2019 might also have qualified as a Category 6, with winds close to 200 mph. 

These type of super storms look like they're going to be more and more common with climate change. 

As Axios explains:

"(The study) also finds that human-caused climate change has more than doubled the res, of Category 6-strength storms since 1979, buy investigating shifts in metric called potential intensity."

I'm not going to get into the weeds on potential intensity, but the bottom line is some hurricanes are going to get a lot stronger than such storms used to be. 

The researchers suggest Category 6 hurricanes should have winds of at least 193 mph, but that figure is not cast in stone. 

While studies are ongoing, there's no word yet as to whether the World Meteorological Organization will sanction category 6 hurricane designations, or when that might happen 

CONE OF UNCERTAINTY

Another big focus is not so much on hurricane intensity but rather the prediction of those storms. 

A cone of uncertainty map for Hurricane Ian in 2022.
Changes are proposed for this type of map to help
the public better understand the dangers they face. 

Those who have ever seen hurricane forecasts have seen the "cone of uncertainty." That's the range of paths the center of a hurricane might take. 

For instance, a forecast might have a hurricane making landfall in say, Charleston, South Carolina.

 But at the point you see the prediction, the range of possibilities for landfall is as far south as Savannah, Georgia or as far north as Wilmington, North Carolina. That question are is known as the cone of uncertainty.   

It turns out, though, that this forecasting method can confuse or mislead some people in the possible path of danger. So the National Hurricane Center is coming up with a potential fix.

The Washington Post reports:

"The hurricane center will issue an experimental version this year that will depict watches and warnings for inland tropical storms and hurricanes, superimposed on top of the forecast cone, aiming to communicate not just the storm path but the extent of its potential impacts. 

It could prevent a repeat of Hurricane Ian, when many Floridians said the cone was a reason they underestimated the 2022 storm's widespread and severe effects."

 NHC always includes this disclaimer with a hurricanes cone of uncertainty: "Note: The cone contains the probable path of the storm center but does not show the size of the storm. Hazardous conditions can occur outside of this cone."

But as the Washington Post noted in an article not longer after Hurricane Ian in 2022:

"But the disclaimer is often stripped off versions of the cone displayed on television, and research has repeatedly shown that a minority of people understand what the cone does and does not depict.

Of 2,847 Floridians surveyed, almost half incorrectly believed that areas outside the cone were safe from hurricane damage."

Even if the cone of uncertainty turns out to be correct, damaging winds, destructive storm surges, and dangerous inland flooding routinely occurs outside that area. 

The new maps will depict the locations of hurricane and tropical storm warnings to better convey where the hazard risks are. A shortcoming to this is there isn't a good way to also include risks posed by storm surges and inland flooding without making the  cone of uncertainty maps confusing and too cluttered.

The National Hurricane Center does have separate graphics for storm surge and inland flood warnings. But that cone of uncertainty is what usually makes it on the evening news.  

Conveying the risks from hurricanes to the public will always be a challenge, but I'm glad people are trying to improve things the best they can.