Hurricane Charley to be upgraded?

[eye of the storm]

Article published Jan 25, 2005
Scientific jury, although not public one, still out on Hurricane Charley

Hurricane Charley may go down as one of the four most powerful storms in modern U.S. history.

In the past 100 years, only three Category 5 hurricanes with sustained winds greater than 155 mph have made landfall.

They were the 1935 Labor Day hurricane, which hit the Florida Keys; Camille, which struck Mississippi in 1969; and Andrew, which wracked Dade County in 1992.

Officially, Charley has been classified as a Category 4 storm with winds of 131-155 mph.

That could change as scientists collect and analyze the data, according to Wayne Salladé, director of emergency management for Charlotte County.

He said Charley registered winds of 173 mph in Punta Gorda and 165 mph at the Charlotte County Airport, but he doesn't know if the velocity held for at least a minute to meet the threshold for upgrading the storm.

It took 10 years for meteorologists to recognize the severity of Andrew's winds, Salladé said Monday morning at an appearance before the West Charlotte County Civic Association.

For perspective, the winds in a Category 5 hurricane are 100 times more powerful than those of a Category 1 (74-95 mph) and likely to cause 250 times the damage, Salladé said.

But Charley's wind speed is a cerebral discussion anyway. Those of us who lived through the Aug. 13 storm and continue to live with its aftermath have had to come to grips with more relevant numbers. In Charlotte County:

n6,000 mobile homes destroyed;

n3,000 conventional homes destroyed;

n27,000 roofs damaged or destroyed;

n41,000 pool cages damaged or destroyed.

Damage statewide added up to $3.2 billion.

Take a slow drive down U.S. 41. On the west side, from Murdock to Charlotte Harbor, about 60 percent of the businesses are gone, Salladé said. That's a lot of jobs lost and lives altered.

Eight schools sustained substantial damage. Four -- Neil Armstrong, East and Peace River elementary schools, and Charlotte High School -- have to be torn down and rebuilt.

The county lost four fire stations, including a new one in Deep Creek where the department kept its most expensive equipment and where firefighters' families had flocked for safety.

Even so, things could have been a lot worse, Salladé said.

Really.

For all its severity, Charley was a small hurricane, with the smallest eye -- five miles wide -- ever to hit the United States, Salladé said.

It pushed a 7-foot storm surge. In a larger storm, winds of 155 mph could carry a 16- to 18-foot surge. If so, Charlotte's death toll probably would exceed the four inflicted by Charley.

"You know the tsunami? That's a storm surge. And that's how fast it can be pushed in by the right storm," Salladé said. "People don't realize how much worse it would have been if Charley had been a Jeanne or a Frances or an Ivan."

Hurricane season reopens in about four months. Salladé would like to see at least two reactions from Charley:

nAn advance in technology to explain how the storm's winds intensified so quickly from 105 to 150 mph. "Earth gives us reasons. There's a reason. We gotta know why," Salladé said.

nSubstantial discounts by insurance companies to policyholders who strap their roofs, reinforce their garage doors and install stronger windows or shutters.

On an individual level, Salladé continues to advise residents to correct their homes' structural weaknesses, to buy adequate insurance coverage and to stock up on camping supplies in preparation for loss of electricity and water service.

After what we've seen with Charley, he says, "Shame on you if you don't."

[HURAKAN]

It seems that the last word about Charley hasn't being said and a surprising account can happen in the years to come. Time will tell!

[Scorpion]

Charley didnt just suddenly intensify from 105 to 150. It was much more gradual. The hurricane was likely 125-130 mph about 6 hours before landfall, and 115 12 hours before. Recon hadn't gone in there for awhile. Also, I doubt it will be a Cat 5. The FL winds don't support it, of course unless it was still bombing while on land like Andrew.

[Derek Ortt]

charley was 120 at cuba, briefly weakened to 110, and then at 10 a.m. was already back up to 125, 145 at 1, and 150 at 3

it was still quite rapid, but the 11 a.m. advisory was written before the recon came in (that advisory should have been scrapped or a special update should have been issued)

[hurricanetrack]

I would like to know about the pressure relationship for Charley and its surrounding environment. I measured 943 millibars in the dead center of the eye just outside of Punta Gorda on Kings Hwy. Several other chasers in the area also measured similar pressures- in the eye. Typically, I thought cat-5s needed pressure of around 922 or less- maybe even sub 920.

It is hard to believe that Charley was a true category five hurricane- but its winds in GUSTS were certainly there. Even if the surrounding air pressure was about 10 millibars higher than normal- that would only place Charley at 933 millibars- still not low enough to generate 160 mph sustained winds- not that we know of. I think the incredible damage was caused by the simple fact that Charley was intensifiying upon landfall and it was very effecient at bringing some monster gusts down to the surface. I would be shocked if Charley were upgraded to the 4th cat-5 hurricane to have ever hit the U.S. and I would want to see some serious proof in the data.

[Derek Ortt]

the central pressure contributes only indirectly to the wind speed. Tracy was a strong cat 5, despite a 950mb pressure.

This is explained clearly in the gradient wind equation v=-(fr/2)+(((f^2)*(r^2)/2)-(r*(dphi/dn)))^(1/2))

the change in pressure and the radius of curvature (storm size) are the two variables that affect the change in wind speed. The smaller the storm, the larger the wind speed

[MWatkins]

I would like to know about the pressure relationship for Charley and its surrounding environment. I measured 943 millibars in the dead center of the eye just outside of Punta Gorda on Kings Hwy. Several other chasers in the area also measured similar pressures- in the eye. Typically, I thought cat-5s needed pressure of around 922 or less- maybe even sub 920.

It is hard to believe that Charley was a true category five hurricane- but its winds in GUSTS were certainly there. Even if the surrounding air pressure was about 10 millibars higher than normal- that would only place Charley at 933 millibars- still not low enough to generate 160 mph sustained winds- not that we know of. I think the incredible damage was caused by the simple fact that Charley was intensifiying upon landfall and it was very effecient at bringing some monster gusts down to the surface. I would be shocked if Charley were upgraded to the 4th cat-5 hurricane to have ever hit the U.S. and I would want to see some serious proof in the data.

Think your 100% right Mark...we just finished talking about this on the program. This article is...well...to quote an 80's phrase...bunk.

The idea that it took 10 years to upgrade Andrew has no bearing on what will happen with Charley...as you know the upgrade was based on the damage pattern and the scientific research that showed the reduction from recon flight level winds to the surface is less in very strong hurricanes that can translate more energy to the surface...there is 0% chance this will ever be upgraded IMHO. The impliation that Charley will be upgraded in 10 years is...well...goofy.

For some reason the source for this article is a Emergency Manager (and his opinion) and not someone from the scientific community. I think it's misrepresentative and a false anaology by the author...Charley was bad for sure but in the same class as Andrew...pressure background or not...there are similariies for sure but the severity and scope of Andrew was much greater...I think.

MW

[MGC]

I doubt Charley get the coveted Cat 5 trophy. Unless new data supporting a steeper pressure gradient if produced, Charley should remain a Cat 4...........MGC

[Matt-hurricanewatcher]

I think Charley was a cat5. My reason behind that is that reports of over 175 mph(Gust). Plus 99.999 percent of the time the wind gauge never gets the highest winds with in a hurricane. Also remember cyclone tracy??? It had pressure with in the 950s. This hurricane(Charley) way smaller then Andrews(Which like the paper said would be the smallest cat5 to ever hit the United states) Its a 50/50 chance that Charley will be upgraded to cat5!!!

[SouthernWx]

There is NO WAY that Charley will be upgraded to a category 5...

We have much better ways of measuring the true intensity of a major hurricane today near time of landfall vs 1992 when Andrew roared through SoFla..chiefly:

1) operational Nexrad radar within the 125 n mi limit of the velocity mode...

2) eyewall dropsondes...

The only operational NWS radar in Miami at the time of Andrew was the old WSR-57 atop the Gables One Tower (at that time, home of NHC)....it didn't have doppler capability (and was destroyed by Andrew, blown off the roof and 200+ feet to the ground below).

The Nexrad at WSFO Melbourne, FL was operating at the time...but Andrew's small eyewall passed too far south for the velocity info to be utilized (was outside the 125 n mi range). The Nexrad at Miami WSFO, Key West WSFO, and Tampa WSFO weren't operational at that time.

During hurricane Charley, Nexrad velocity data was useful in obtaining a true intensity. Near time of landfall, the Nexrad at Tampa was measuring winds of 165 kt (190 mph) above the surface...reduced to an estimated 10 m sustained wind speed of 132 kt...or 150-155 mph.

Eyewall dropsondes also were utilized during Charley at time of landfall. These did not exist at the time of hurricane Andrew...but new technology developed. Data from similar hurricanes with use of eyewall dropsondes assisted in determining the true intensity of Andrew (comparisms). The peak eyewall dropsonde winds I'm aware of during Charley would correlate to sustained surface winds of 133 kt or 153 mph.

While it is likely hurricane Charley was near the top end of a cat-4 hurricane....IMO 130-135 kts, with peak GUSTS of 160-165 kt, there's no evidence of sustained reaching cat-5 intensity, and will never be.

PW

[HurricaneBill]

What would happen if data indicated sustained winds of 156 mph at the surface? Would they upgrade to Category 5 or round it down to 155 mph. Do they prefer to not upgrade until winds reach 160 mph?

This isn't in regards to Charley. I'm just asking in general.

Personally I think Charley was well on his way to becoming a Category 5 hurricane but wasn't quite there at time of landfall.

Like many intensifying hurricanes, Charley ran out of time.

[weatherlover427]

the central pressure contributes only indirectly to the wind speed. Tracy was a strong cat 5, despite a 950mb pressure.

This is explained clearly in the gradient wind equation v=-(fr/2)+(((f^2)*(r^2)/2)-(r*(dphi/dn)))^(1/2))

the change in pressure and the radius of curvature (storm size) are the two variables that affect the change in wind speed. The smaller the storm, the larger the wind speed

What exactly does this equation represent / compute?

[Stormsfury]

What would happen if data indicated sustained winds of 156 mph at the surface? Would they upgrade to Category 5 or round it down to 155 mph. Do they prefer to not upgrade until winds reach 160 mph?

This isn't in regards to Charley. I'm just asking in general.

Personally I think Charley was well on his way to becoming a Category 5 hurricane but wasn't quite there at time of landfall.

Like many intensifying hurricanes, Charley ran out of time.

When rounded into knots vs. statute miles for CAT 4 vs. CAT 5. 135 kts=155 kts, 140 kts=161 kts... so there wouldn't be any doubts to a rounding down or up in this case ...

As for the status of Hurricane Charley ... CAT 4 ... SouthernWx pegged it right on the head ... what we dealt with is a rapidly deepening cyclone, but NOT explosive, entering a favorable position around the base of a very strong August trough which not only enhanced the intensification process, but also RELATIVE shear was virtually nil., and Charley progressed at roughly 20 MPH, which in turn lopsided the strongest core of winds on the N and E quadrant of the storm ... the winds on the western side of Charley were much, much less than the strongest core of winds.

Charley was a very small, intense, and compact hurricane, but one, didn't have the time to fully reach max potential (which more time over water in a favorable position relative to the trough positioning, MIGHT have been able to strength a little more). Mark Sudduth's positioning (as well as other chasers) recorded pressures in the 943-945 mb category, a full 20 MB higher than Andrew. Andrew had more time to intensify and actually had two peaks, before the Bahamas, and just reaching the Coast of Florida. Back to Mark's video. I watched the video, and yes, very severe winds, easily validated with the winds recorded from his chase vehicle, but had CAT 5 winds occurred, trees would have been flattened, and honestly, Mark's vehicle, and others I don't think would have been able to sustain that kind of abuse.

SF

[Stormsfury]

the central pressure contributes only indirectly to the wind speed. Tracy was a strong cat 5, despite a 950mb pressure.

This is explained clearly in the gradient wind equation v=-(fr/2)+(((f^2)*(r^2)/2)-(r*(dphi/dn)))^(1/2))

the change in pressure and the radius of curvature (storm size) are the two variables that affect the change in wind speed. The smaller the storm, the larger the wind speed

To add to this, for others ... Cyclone Tracy's size was only 50 MILES ... and that's the ENTIRE STORM diameter (a micro-cyclone, in relative terms to tropical cyclones). The pressure gradient was extreme, and unheard of ...

SF

[Derek Ortt]

that equation I typed gives a good approximation of the wind speed in a tropical cyclone

[MGC]

Hey Derek, how about sharing with us the variables used to compute the velocity. Like what does dphi stand for?......MGC

[Derek Ortt]

variables used in the grad wind equation

f = corolis parameter: This is equal to 2*omega*sin(latitude) (omega is roughly equal to 7.27*10 to the 10-5 )

r= radius of curvature. In other words, the storm radius

dphi/dn is the partial derivative of geopotential height with respect to distance, using natural coordinates. To simplify things, this can be treated as the change in geopotential divided by the change in distance. geopotential is the gravitational force* height so the differential of this is g*the change of height

[MGC]

Thanks Dereck, looks like I'll have to dust off my old calculus book. Now what box in the attic is my slide rule in?...........MGC

[DoctorHurricane2003]

Posted by Derek Ortt:
the central pressure contributes only indirectly to the wind speed. Tracy was a strong cat 5, despite a 950mb pressure.

Actually, STC Tracy was a category 4 on the ATCI Scale (which corresponds to maximum wind gusts of 225-279 km/h or 141-174 MPH.) This would likely make Tracy a strong 3 or a 4 on the Saffir-Simpson Scale, but certainly not a 5.

The Darwin airport recorded a wind gust of 217 km/h before the instrument failed. This would probably make Tracy comparable in strength to Luis before it hit the Leeward Islands in 1995. The reason for such a widespread amount of damage that looked catastrophic is most likely due to the Australian building codes at that time, which were not as strict as today's standards.

Edit: It would probably fit even better to compare Tracy to Iris in 2001...I should probably add that the 950 hPa situation is probably comparable to when Hurricane Iris hit Belize with a pressure of 954 mb and a wind speed of 125 KTs.

Information provided by the Bureau of Meteorology of the Australian Government. http://www.bom.gov.au/