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Atlantic Tropical Action 2012 - Part II


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An enormous hurricane in size in literature is different than an enormous hurricane in size in (re)analysis, as snowflake just highlighted. And the 115 kt reanalysis wasn't my point, I never said that it wasn't a strong hurricane. And I also never said that the damage calculation wasn't off.

And I'm comparing it to damage totals (normalized) for two storms that struck a similar area, albeit the 1947 hurricane was a bit weaker and likely somewhat smaller than 1926 and 1928.

It is described as a large hurricane in reanalysis. Have you read the reanalysis papers on it?

And since when is hurricane winds more than 105 n mi from the center not large? Ya lost me here.

1947 was not smaller than 1926-- it was weaker, but not smaller. Where are you getting this info?

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It is described as a large hurricane in reanalysis. Have you read the reanalysis papers on it?

And since when is hurricane winds more than 105 n mi from the center not large? Ya lost me here.

Yes.

And for the second part, I'm referring to sustained winds, and quoting this part of snowflake's post.

The 110 n mi reported was likely based upon gusts, not sustained winds...as gusts to hurricane intensity were reported from Carysfort Reef to Cape Canaveral.
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Yes.

And for the second part, I'm referring to sustained winds, and quoting this part of snowflake's post.

Yes, but then I clarified that the sustained hurricane winds still likely extended up to 105 n mi from the center, as Josh mentioned. Please read my entire post(s).

For the record, my views on the size of the 1926 hurricane are expounded here, with actual evidence cited and, whenever and wherever possible, sourced.

Since we are getting off topic, we might want to start a new thread...?

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Yes.

And for the second part, I'm referring to sustained winds, and quoting this part of snowflake's post.

Snowflake's post also said sustained hurricane winds were over 100 n mi from the center.

Reanalysis papers show a RMW of 27 n mi-- way larger than the climatological norm of 16 n mi for this latitude and intensity. The 1926 storm had a RMW of ~20 n mi-- it was more average, and it was smaller than 1947.

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Snowflake's post also said sustained hurricane winds were over 100 n mi from the center.

Reanalysis papers show a RMW of 27 n mi-- way larger than the climatological norm of 16 n mi for this latitude and intensity. The 1926 storm had a RMW of ~20 n mi-- it was more average, and it was smaller than 1947.

That's not what I'm seeing, unless we are reading different re-analysis papers.

On the 2012 revision I am reading, the 1926 cane and 1947 cane both have RMWs of 20 n mi.

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Yes, but then I clarified that the sustained hurricane winds still likely extended up to 105 n mi from the center, as Josh mentioned. Please read my entire post(s).

For the record, my views on the size of the 1926 hurricane are expounded here, with actual evidence cited and, whenever and wherever possible, sourced.

Since we are getting off topic, we might want to start a new thread...?

Agreed.

Mods, please separate out this debate Re: historic hurricanes.

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Snowflake's post also said sustained hurricane winds were over 100 n mi from the center.

Reanalysis papers show a RMW of 27 n mi-- way larger than the climatological norm of 16 n mi for this latitude and intensity. The 1926 storm had a RMW of ~20 n mi-- it was more average, and it was smaller than 1947.

Actually, Josh, a slight correction is needed: the updated paper by Hagen et al. (2012), in its table of U.S. impacts (Table 3), lists an RMW of 20 n mi for the 1947 hurricane and 945 mb, not 940 mb, as the central pressure. So 1926 and 1947 were of similar size in that regard.

Based upon this list as well as the paper, here are the two storms side-by-side:

1926: 20 n mi RMW, OCI 1008 mb at 325 n mi wide, 930 mb, 125 kt

1947: 20 n mi RMW, OCI 1010 mb at 275 n mi wide, 945 mb, 115 kt

Largest RMW: Neither (same)

Largest outer closed isobar / OCI: 1926

So 1926 was a bit larger than 1947, but not by much.

(Andy beat me to the punch. tongue.png )

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That's not what I'm seeing, unless we are reading different re-analysis papers.

On the 2012 revision I am reading, the 1926 cane and 1947 cane both have RMWs of 20 n mi.

OK, I went back and looked, and there seems to be a discrepancy. In Hagen's thesis it says 27 n mi, whereas in the "preliminary" paper for the Journal of Climate, it says 20 n mi. That's a big change with no explanation in the text, so I'm going to investigate it

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Actually, Josh, a slight correction is needed: the updated paper by Hagen et al. (2012), in its table of U.S. impacts (Table 3), lists an RMW of 20 n mi for the 1947 hurricane and 945 mb, not 940 mb, as the central pressure. So 1926 and 1947 were of similar size in that regard.

(Andy beat me to the punch. tongue.png )

Yeah, I just checked but that's a huge change with no explanation at all, so I want to look into that a little more.

Keep in mind: Hagen did not actually analyze that storm-- it was done by someone else, and incorporated into his paper-- so I want to got back to the source. There should be some metadata justifying the change. Other literature-- including sources like the MWR-- have always described it as a very large storm with very large radii.

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OK, I went back and looked, and there seems to be a discrepancy. In Hagen's thesis it says 27 n mi, whereas in the "preliminary" paper for the Journal of Climate, it says 20 n mi. That's a big change with no explanation in the text, so I'm going to investigate it

I contacted one of the co-authors some time ago and the reason for the change was related to new evidence made by a researcher that the RMW was a bit smaller than the 27 n mi, which was based upon an earlier 1987 study (see Table 2) by Ho et al. That earlier study gave the landfall point a tenth of a degree farther N than Hagen et al. did. The initial Hagen paper forgot to adjust the RMW 5 n mi or so smaller to account for the ~7 n mi difference between the two landfall points. Also, the additional evidence I mentioned, including recently uncovered data from SE FL, supported 20 rather than 27 n mi. (The new data also helped change the central pressure from 940 mb in the initial study to 945 mb in the preliminary reanalysis.)

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I contacted one of the co-authors some time ago and the reason for the change was related to new evidence made by a researcher that the RMW was a bit smaller than the 27 n mi, which was based upon an earlier 1987 study (see Table 2) by Ho et al. That earlier study gave the landfall point a tenth of a degree farther N than Hagen et al. did. The initial Hagen paper forgot to adjust the RMW 5 n mi or so smaller to account for the ~7 n mi difference between the two landfall points. Also, the additional evidence I mentioned, including recently uncovered data from SE FL, supported 20 rather than 27 n mi. (The new data also helped change the central pressure from 940 mb in the initial study to 945 mb in the preliminary reanalysis.)

I see what you and Andy are saying-- that it was revised down to 20 n mi-- and I'm not totally buying it, since it's always been described as a very large hurricane with tremendous radii. While reanalysis corrects details, like estimated wind speeds, it usually doesn't change general characteristics-- for example, turning a large hurricane into an average-size hurricane. This goes beyond the confusion around the exact landfall point, and whether it was 5 n mi this way or that. The 1947 storm has always been described in the literature as very large. The MWR, which reanalysis uses as a basic source, says: "The great expanse of coast subjected to hurricane force winds, from this storm that moved inland at right angles to the coast line, classes it as one of the great storms on record." And it describes various wind radii that paint a picture of an awesomely large system.

Given this, I'm not buying the revision until I see metadata or discussion around this change. Justification is needed, because that's not how the storm has been historically described by reliable sources.

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I owe some responses Re: this Sandy-vs.-1938 debate and will get to those laterz... biggrin.png

But in the meantime, here's the preliminary track map for this season. I have to say, it's such a horrible tease that Sandy's classification is changed to extratropical literally at the coast. laugh.png

My weenie side is taking over here-- but I can't help wishing they'd just designate this a hurricane landfall for NJ, given the enormity of the impact, its obvious historical significance, and the fact that the public will always think of it as a hurricane impact. I know, I know-- it's not a scientific viewpoint, but I think it's enough of a grey area and an argument can be made. It still had some tropical characteristics, including 1) obvious warm core, 2) apparent wind core, and 3) convection near if not over the center. Also of note: although significant damage occurred far from the center-- as far away as RI-- it seems the greatest destruction occurred relatively close to the center-- on the C and N NJ coasts and Metro NYC.

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The incredible thing about this image is that there were only 2 hurricanes below 25N this year. Really shocking when you look at it graphically.

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  • 2 weeks later...

A very interesting week ahead in the Atlantic. GFS and Euro both develop a tropical / sub-tropical low around 30N/45W within the next couple days. The circulation is already discernible on vis and IR. The low then tracks poleward and becomes supported baroclinically, while maintaining a warm core beneath the subtropical ridge. You can see the beautiful jet streak develop to its northeast with the low level circulation superimposed under the equatorward entrance region.

You can track the supporting disturbance at the tropopause back to the feature currently located over South Dakota.

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Might be under 40 or 50 knots of shear in the Caribbean, but one last 0% lemon of the season might be nice.

Canadian has a post season system of non-tropical origin, by 180 hrs under an anticyclone aloft in the middle of nowhere.

Canadian system in Rainstorm imagery.

slp24.png

Canadian forecast blob has been lemonized...

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