Atlantic Hurricanes: Reanalyzed

[HurricaneJosh]

reanalyze something interesting next time!

WTF?

[HurricaneJosh]

What about writing one? I did the featured article on Carmen '74 (took several days of work and research, which I guess qualifies), and I'd be interested to see a reanalysis of the storm's intensity between its official upgrade to Cat 4 and its first landfall. The apparent ERC and northern jog suggest there are some undocumented fluctuations in peak winds. Just a thought.

If you'd like to share your analysis, please do. I did some light research on that one last year, and as I understand it, Carmen's Yucatan landfall was solid Ca 4-- however, it really fell apart approaching LA and, if anything, I'd think it could be downgraded for the USA landfall.

[Juliancolton]

If you'd like to share your analysis, please do. I did some light research on that one last year, and as I understand it, Carmen's Yucatan landfall was solid Ca 4-- however, it really fell apart approaching LA and, if anything, I'd think it could be downgraded for the USA landfall.

I haven't really done an in-depth, point-by-point analysis – my research was mostly impact-related – which is why I'd like to see someone take a look at it (since HURDAT won't get around to it for quite a while ). Agree that the US landfall is shaky, but I'm more interested in the slight oscillations that saved Belize City from major destruction. Maybe I'll go through the NHC wallet and see what I can get.

[HurricaneJosh]

I haven't really done an in-depth, point-by-point analysis – my research was mostly impact-related – which is why I'd like to see someone take a look at it (since HURDAT won't get around to it for quite a while ). Agree that the US landfall is shaky, but I'm more interested in the slight oscillations that saved Belize City from major destruction. Maybe I'll go through the NHC wallet and see what I can get.

Yeah, one of the reasons I've gotten so interested in reading these reanalysis papers and doing my own reanalysis is because the official HURDAT updates are just going to take a while-- and in the meantime, I'd rather have improved data even if it's not officially approved.

Carmen's track might have been good for Belize City, but it absolutely raked Chetumal, which was in the S eyewall and reported 118 kt sustained.

[k***]

carmen is one worth doing a detailed analysis on.

[HurricaneJosh]

carmen is one worth doing a detailed analysis on.

I'd be interested to see it. Perhaps Julian might indulge us at some point.

The 118 kt (1-min) from Chetumal-- in the S eyewall-- was pretty hawt. (The LA landfall-- not so hawt.)

[k***]

I'd be interested to see it. Perhaps Julian might indulge us at some point.

The 118 kt (1-min) from Chetumal-- in the S eyewall-- was pretty hawt. (The LA landfall-- not so hawt.)

Now that's a real cat 4...not this 115kt crap

You have to wonder if it was pushing a 5? One of my favorite double eyewalls ever.

[Floydbuster]

I'm most interested in re-analysis of Hurricanes Carla and Camille.

One thing that ruins the rhetoric of downgrading Camille to a Category 3 or 4 storm is the extreme landfall pressure coupled with the small inner core. Now, if Camille had a ragged, open dry-air intruded eye on radar, then yes, it was weaker. However, Camille held a tiny, perfect Andrew-like core into landfall and coupled with a 909 mb pressure, I have no doubt winds of 160-165 mph occurred at landfall. 190 mph? No. Category 5 strength though? Yes.

[HurricaneJosh]

I'm most interested in re-analysis of Hurricanes Carla and Camille.

One thing that ruins the rhetoric of downgrading Camille to a Category 3 or 4 storm is the extreme landfall pressure coupled with the small inner core. Now, if Camille had a ragged, open dry-air intruded eye on radar, then yes, it was weaker. However, Camille held a tiny, perfect Andrew-like core into landfall and coupled with a 909 mb pressure, I have no doubt winds of 160-165 mph occurred at landfall. 190 mph? No. Category 5 strength though? Yes.

How do you know Camille's eyewall was so nice? Were the radar shots that revealing?

I agree it was a Cat 5, but in the low-end of the range. The central pressure, RMW, latitude, and intensity trend would suggest ~140 kt, I would think.

[k***]

How do you know Camille's eyewall was so nice? Were the radar shots that revealing?

I agree it was a Cat 5, but in the low-end of the range. The central pressure, RMW, latitude, and intensity trend would suggest ~140 kt, I would think.

the radar looks as good as any i have ever seen from a non-nexrad source. Slam dunk category 5.

[Srain]

[HurricaneJosh]

the radar looks as good as any i have ever seen from a non-nexrad source. Slam dunk category 5.

It does look a little better than I remembered it. Do you know the timing of those images, and are there higher-res versions anywhere? I assume this is the New Orleans radar?

I don't know if I would say "slam dunk", but the imagery certainly doesn't hurt the Cat-5 argument.

[HurricaneJosh]

That Pensacola shot from Steve does look pretty nice-- especially given the distance. That eyewall is circular and distinct, with a moat around it. And it's fairly near the coast.

[Srain]

That Pensacola shot from Steve does look pretty nice-- especially given the distance. That eyewall is circular and distinct, with a mote around it. And it's fairly near the coast.

There is a pretty good argument for concentric eyewalls as well.

[HurricaneJosh]

Looking at the radar shots with fresh eyes-- after not having reviewed them in a long while-- reinforces my feeling that Camille had winds of ~140 kt at landfall in MS.

[k***]

There is a pretty good argument for concentric eyewalls as well.

Definitely. But it looks more like one of the beastly concentrics instead of the lamer ERC-imminent versions. More Gilbert than Earl IMO.

[Scott747]

I know it won't be upgraded. Still close to being a five at landfall and probably doesn't get enough respect for being in that elite class of storms that were just a whisk away of being a legendary cat five landfall. Lower pressure readings would have helped the argument.

[HurricaneJosh]

I know it won't be upgraded. Still close to being a five at landfall and probably doesn't get enough respect for being in that elite class of storms that were just a whisk away of being a legendary cat five landfall. Lower pressure readings would have helped the argument.

Well, that crazy wind reading from Paseo Real de San Diego (135 kt G 184!!) supports Cat-5 intensity, if you take it at face value. (Yes, it's a Cat-4 wind, but one can always assume the highest winds weren't sampled.) But that's a big "if". I can't help feeling knee-jerk skepticism when I see such an extreme value like that. I dunno. Are there are any photos of that weather station or the surrounding 'hood immediately following the 'cane? There should have been heavy structural damage if such winds occurred-- with the trees all reduced to sticks.

The landfall pressure of 943 mb leaves me less convinced Re: Cat-5 status. Even taking account the fact that it was bombing out, 943 mb is really high for 140 kt, even if we're dealing with a microcane, and Gustav was no micro. (At landfall in Cuba, Gustav's dimensions were: 64-kt radius = 70 mi, 34-kt radius = 175 mi.) As has been suggested before, that extreme wind reading might have been the result of some localized topographical augmentation.

P.S. It's hard to believe this is the the same cyclone that ended up being such a complete flop when you and I chased it across the Louisiana bayous.

[HurricaneJosh]

Here's an interesting paper by Chris Landsea and friends, in which ten very important mid-century American 'canes are reanalyzed: http://www.aoml.noaa.gov/hrd/hurdat/10_US_hurricanes.pdf

I was previously aware of these findings, but had never seen them summarized in a single paper before.

Please note that these findings have not been presented to (or approved by) the NHC best-track committee yet, so none of these revised intensities are official. Still, these conclusions represent the tropical community's best thinking about these cyclones to date.

Of the ten cyclones, eight are important East Coast events, so I thought I'd highlight those findings, as they're of particular interest to this forum's membership:

Long Island (New England) Hurricane 1938

Landfall in NY: 105 kt

States Impacted: NY3, CT3, RI3, MA2

Comments: MA impact is reduced to Cat 2.

Great Atlantic Hurricane 1944

Landfall in NY: 95 kt

States Impacted: NC2, VA2, NY2, CT1, RI2, MA1

Comments: Impact in all regions was previously overestimated and is lowered at least 1 category for each state. Clearly, the legendary Cape Henry, VA, reading (117 kt sustained) was not accepted as credible. lolz

Fort Lauderdale Hurricane 1947

Landfall in FL: 115 kt

Landfall in LA: 95 kt

States Impacted: FL4, LA2, MS2

Comments: FL intensity reduced significantly from the previous 135 kt, as the notorious reading from Hillsboro Light (135 kt (1-min)) is not believed to be credible-- and, also, the accepted pressure-wind relationship does not support such a high wind value for a large system (RMW 27 nmi) with a central pressure of 940 mb. The estimated impact on the Gulf Coast is also reduced.

Carol 1954

Landfall in NY: 100 kt

States Impacted: NC1, NY3, CT2, RI3, MA2

Comments: Cyclone was small for this region (RMW 22 nmi) and was moving very fast (40 kt), thus boosting estimated wind. The CT impact is downgraded from previous as it was on the weaker side.

Edna 1954

Landfall in MA: 105 kt

States Impacted: NC1, NY1, RI1, MA3

Comments: Cyclone was small for this region (RMW 20 nmi) and was moving fast (35 kt), thus boosting wind estimate. The ME impact is removed, despite winds still being 75 kt, as the cyclone was extratropical by that point. (Poor ME! )

Hazel 1954

Landfall in NC: 115 kt

States Impacted: SC3, NC4

Comments: Under the harsh light of modern reanalysis, this legendary cyclone barely squeaks by as a Cat 4. The SC impact is reduced a category because the center crossed at the SC/NC state border and SC was on the weaker side. Although VA and DC observed sustained hurricanes winds-- and MD, PA, and NY probably did-- these are not counted as hurricane impacts because the cyclone was fully extratropical before it even exited NC.

Donna 1960

Landfall in FL (Keys): 115 kt

Landfall in FL (SW Coast): 100 kt

Landfall in NC: 95 kt

Landfall in NY: 85 kt

States Impacted: FL4, NC2, VA1, NY2, CT1, RI1

Comments: Estimated intensity in FL is a little lower than previously thought. Estimated impacts from NC to New England have been reduced by at least 1 category per state. (It was previously considered a Cat 3 in NC and NY and a hurricane up to ME.) RMW was a whopping 48 nmi over NY, thus reducing the wind estimate. NH and ME impacts are removed, as hurricane winds were probably only occurring offshore by that point.

Gloria 1985

Landfall in NC: 85 kt (higher winds offshore)

Landfall in NY: 75 kt

States Impacted: NC2, NY1, CT1, MA1, NH1

Comments: Lameness all around. Category assignments reduced in NY/New England. The exclusion of RI strikes me as an oversight, as it wouldn't make sense that CT and MA had a hurricane impact, but not RI.

[Ed Lizard]

I survived Hurricane Belle.

Even as a young'un, I was grossly disappointed.

[wxmx]

Even though there were many "downgrades", the main reason was because how the SS scale was implemented (categories based solely on central pressure). There were actually many upgrades in the wind speeds during and prior to landfall. Using wind speed (as it should be), the more tropical track (cyclone while near the tropics) was usually penalized, while the mid latitudes were boosted (1934 TX, 1947 Fort Lauderdale prior to FL LF --LA LF was boosted, though-- and Donna were downgraded, for example... Gloria is a counterexample of this, though).

Another interesting tidbit, if this reanalysis paper was to be approved, we would lose 2 cat 5s (Fort Lauderdale and Donna)

[HurricaneJosh]

Even though there were many "downgrades", the main reason was because how the SS scale was implemented (categories based solely on central pressure). There were actually many upgrades in the wind speeds during and prior to landfall. Using wind speed (as it should be), the more tropical track (cyclone while near the tropics) was usually penalized, while the mid latitudes were boosted (1934 TX, 1947 Fort Lauderdale prior to FL LF --LA LF was boosted, though-- and Donna were downgraded, for example... Gloria is a counterexample of this, though).

Agreed-- I should have more explicitly pointed out that in many cases, the previously-assigned state impacts were downgraded while winds were actually upgraded.

But I find the 1947 (FL), Hazel, and Donna (FL) wind reductions interesting-- as those were clear examples of that mid-century puffery I always speak of.

[wxmx]

Agreed-- I should have more explicitly pointed out that in many cases, the previously-assigned state impacts were downgraded while winds were actually upgraded.

But I find the 1947 (FL), Hazel, and Donna (FL) wind reductions interesting-- as those were clear examples of that mid-centrury puffery I always speak of.

Yeah, but the greater reductions are close to the tropics.

[HurricaneJosh]

Yeah, but the greater reductions are close to the tropics.

Agreed.

Gloria is actually not a counterexample, however-- as the 75 kt for NY is as originally assessed (and the NC wind is almost the same as originally assessed).

[wxmx]

Agreed.

Gloria is actually not a counterexample, however-- as the 75 kt for NY is as originally assessed (and the NC wind is almost the same as originally assessed).

When was moving west, near the tropics.

[HurricaneJosh]

When was moving west, near the tropics.

Gotcha. I thought you meant the up-N verdicts.

[Hugo]

Josh, I have a funny Hazel story I thought you'd like. If you use the NOAA's precise point of landfall for Hazel, it was at Little River, SC, about 500 yards SE of the SC/NC border. NC tropical weenies of course always like to take credit for Hazel, but the state itself vehemently points out that landfall was technically in SC. The reason is that, if you want to be overly intellectual on it, NC has never had a Cat 4, therefore it's harder for insurance companies to jack up rates in the state. This came up a few years ago because one of the big companies (Allstate?) jacked up rates along the entire coast of NC, citing "a high probability of a Cat 4+ hurricane landfall along the coast."

[HurricaneJosh]

Josh, I have a funny Hazel story I thought you'd like. If you use the NOAA's precise point of landfall for Hazel, it was at Little River, SC, about 500 yards SE of the SC/NC border. NC tropical weenies of course always like to take credit for Hazel, but the state itself vehemently points out that landfall was technically in SC. The reason is that, if you want to be overly intellectual on it, NC has never had a Cat 4, therefore it's harder for insurance companies to jack up rates in the state. This came up a few years ago because one of the big companies (Allstate?) jacked up rates along the entire coast of NC, citing "a high probability of a Cat 4+ hurricane landfall along the coast."

That is a great story-- and so indicative of the slight arbitrariness of these verdicts-- no matter how thoughtful they are. In the end, there's something slightly academic about it all.

The funny thing is that even if Hazel came ashore on the SC side, NC really got the Cat-4 conditions.

[Ed Lizard]

Does North Carolina have a compulsory insurance pool that all insurers in the state are required to be members of, to insure properties in coastal counties?

Florida has one, IIRC.

[Hugo]

Situation: Hurricane Hugo makes landfall at Mechanicsville, SC at 12:00 am EDT, 09/22/1989.

Argument by some mets: Hugo managed to clear cut pine forests 20-25 miles inland. Some of the trees were uprooted and literally blown away from the site they had stood. Because of this, there is a strong argument that Hugo may have been a Category Five at landfall. Tree damage to some of the area was worse that in Tatum, SC, where two F-4 tornadoes crossed paths within 10 minutes of each other 5 years prior.

Discuss.