Cat 4 hurricanes very unlikely north of Florida on E Coast

[Derek Ortt]

http://ams.allenpress.com/amsonline/?re ... JCLI3913.1

this is the abstract to a study published in the July issue of the Journal of Climate by Jaggar and Elsner, which I am currently reading, relating to the return periods of certain hurricane windspeeds on the East Coast. 117KT has a return period of 100 years, meaning that one should not expect cat 4's to strike the EC, north of Florida with any frequency, and those that do truly are rare events. Gulf Coast has higher return periods, though those may be high due to most of the cat 4's striking in the early part of the 20th century, when the reanalysis used the standard pressure to wind relation and not the Gulf press to wind

[Derek Ortt]

not that I am surprised by the Jaggar and Elsner study, as the only cat 4 hurricane that I know of to hit the EC north of Florida was Hugo

Not that the EC should not take major hurricanes seriously, as the return period of cat 3's is much more frequent and as we saw last year, cat 3's are very destructive events

[OuterBanker]

Don't forget Hazel.

[Derek Ortt]

http://weather.unisys.com/hurricane/atl ... /track.dat
http://weather.unisys.com/hurricane/atl ... /track.gif

Hazel weakened from a 4 to a 3 just before landfall, according to the HURDAT best track. The cat 4 rating was based strictly upon the 937mb pressure... but we now do not associate 110KT hurricanes with cat 4 intensity

[Hybridstorm_November2001]

We do not have a reliable long enough data set to make such assumptions.


BTW There is evidence that points towards Hugo being a cat 5 at SC landfall, but nothing has been decided definitively on reanalysis yet. Same goes for Hazel being a cat 4, rather than 3, at landfall.

[terstorm1012]

We do not have a reliable long enough data set to make such assumptions.


BTW There is evidence that points towards Hugo being a cat 5 at SC landfall, but nothing has been decided definitively on reanalysis yet. Same goes for Hazel being a cat 4, rather than 3, at landfall.

yeah you and derek have been hinting at that for months. Curiousity peaked now...wanna know more

[Derek Ortt]

Yes, Hugo could have been a 5 at landfall very easily based upon the NHC's own report and whatw e know now about reduction factors. However, this would not change the return period of cat 4's, but would change the return period of cat 5's (which are close to statistical impossibilities assuming Hugo was a 4)

[Derek Ortt]

I don't know, BECAUSE I'M A MET. But I will take the scientific consensus

[Dr. Jonah Rainwater]

Guys I have a fantastic idea. Let's talk about hurricanes.

[Derek Ortt]

I would also think that Hazel was a 3, despite its very fast forward speed enhancing the windfield, because it was largely baroclinic, which would have caused a broad and spread out wind field, which it has, along with the peak winds being located well above the surface

[canegrl04]

Cat4/5 hurricanes are for S.FL,and the GOM

[windycity]

I agree. The northern east coast SSTs can not usually support a cat 4 or 5.

[Matt-hurricanewatcher]

I would say its less likely for a cat4(135mph+) to hit the northeast gulf coast north of Tempa bay to The border of Florida and AB. The last few years have proven this very much so. Also you look at the sst's over that part of the gulf you will see.

I think cat4s are more likely to hit Ga,SC if not much more then the northeastern gulf.

Most likely because of the Gulf stream laying off the east coast...While theres a cold pool over the northeastern Gulf.

[Huckster]

From 1851-1900, 5 category 4 hurricanes hit the U.S. Four of these struck the Gulf Coast. There's no doubt that the Gulf Coast will get hit more often by cat. 4 hurricanes than the EC north of Florida. That being said, the lone cat. 4 hurricane during that period to hit north of Florida made landfall in GA.

[Dr. Jonah Rainwater]

Hugo was a solid Category 4 at landfall. Hazel might have weakened to a Cat3 just offshore like Katrina did, but she brought in the surge of a 4. Diana, Gracie, and Helene all came extremely close to landfalling at Cat 4 intensity. In addition, enough storms have rapidly intensified to Cat4 just offshore the East Coast to make me think that landfalls are perhaps not as statistically improbable as the last few decades would have you believe.

[Matt-hurricanewatcher]

Yes the western and central gulf coast is much more likely to support cat4's. Which is east of 87 west. But east of there you have low TCHP which means low heat/energy for the hurricane to feed off of. Even so katrina,Lili(2005,2002) both fall apart. I think it was more because of dry air,mid level shear caused by the system that picked it up. But systems that fall pass 87 will fall apart which where Opal,Ivan,Dennis to name a few.

[Stormcenter]

Yes the western and central gulf coast is much more likely to support cat4's. Which is east of 87 west. But east of there you have low TCHP which means low heat/energy for the hurricane to feed off of. Even so katrina,Lili(2005,2002) both fall apart. I think it was more because of dry air,mid level shear caused by the system that picked it up. But systems that fall pass 87 will fall apart which where Opal,Ivan,Dennis to name a few.

Well I wish Katrina would have "fallen apart" a little more for the sake of the Gulf Coast residents.

[MiamiensisWx]

Well I wish Katrina would have "fallen apart" a little more for the sake of the Gulf Coast residents.

Actually, even if Katrina had weakened to a Category One or Category Two before landfall, it would have still made little difference. It would have still carried a huge wind swath, destructive Category One/tropical storm-force winds, and would still bring in a tremendous surge.

[Noles2006]

Well I wish Katrina would have "fallen apart" a little more for the sake of the Gulf Coast residents.

Actually, even if Katrina had weakened to a Category One or Category Two before landfall, it would have still made little difference. It would have still carried a huge wind swath, destructive Category One/tropical storm-force winds, and would still bring in a tremendous surge.

Disagree. If it had weakened all the way to a Cat 1 or 2 instead of borderline Cat-4, there would have been a much smaller surge. It would have made a HUGE difference, IMO, as the wind field, while still large, would have been weaker.

[boca]

Yes, Hugo could have been a 5 at landfall very easily based upon the NHC's own report and whatw e know now about reduction factors. However, this would not change the return period of cat 4's, but would change the return period of cat 5's (which are close to statistical impossibilities assuming Hugo was a 4)

Hugo's winds were 135mph at landfall.