Interesting landfall correlation...

[MiamiensisWx]

I have just recently found an interesting "coincidence," if one may deem it such. Currently, there are indications that the western NINO zones—NINO 3, 3.4, and 4—are about to warm up, based upon recent progression of subsurface anomalies. This is making neutral-warm conditions likely for the peak of the Cape Verde season in August-September. Also, the negative Indian Ocean Dipole, or IOD, is often cited as a factor favoring more instability (=greater storm intensity, at least) in the Atlantic Ocean; the IOD is negative this year. I have occasionally heard a theory that, under some conditions, neutral-warm conditions actually tend to shift the Bermuda High farther south and west. This would typically depend, in part, upon the SSTA configuration in the tropical Pacific, usually a warm-cool gradient from near the International Date Line to the Galápagos Islands—a "Modoki"-type situation where NINO 3, 3.4, and 4 are above average and NINO 1 and 2 stay below average.

I did some research and have found that, with a cool Indian Ocean and a "Modoki"-type SSTA configuration, the Bermuda High might tend to shift farther south and west. Given that this year seems likely to be active, and given that SSTA in the tropical Pacific are warming up, I looked at years with similar trends. Years that featured the -IOD / "Modoki" configuration, and which by August-September had warmed up over time, were 1919, 1928, 1965, and 2004. Two other examples, though less clear, were 1929 and 1935. All those years, inclusive, featured all the strongest landfalls in South FL and/or the Central Gulf Coast (LA / MS): the 1919 hurricane, the 1928 hurricane, the 1935 Labor Day hurricane, and Betsy. Frances and Jeanne also struck Central FL in 2004. 1992 did not count because that year was cooling off in the tropical Pacific.

I have seen a study showing that neutral years, as opposed to years that featured La Niña, tended to feature a Bermuda High which was elongated farther south and west, thereby steering more Cape Verde-type systems into South FL and/or the Gulf of Mexico. However, I knew that Pacific SSTA alone were not likely to account for this trend, so I narrowed down the list by looking at IOD. I also looked specifically at neutral-warm years—years which, on the balance, were biased neutral-warm in NINO 3, 3.4, and 4. While I must emphasize that I am not sounding an alarm, the possible correlation looks interesting.

SSTA data are taken from the ERSSTA 3b-NOAA SST dataset:

http://nomads.ncdc.noaa.gov/las/getUI.do

[BigB0882]

Very interesting. Thanks!

[SFLcane]

Interesting indeed..thanks

[artist]

Just don't let it be a repeat of 2004 for Palm Beach county. That's all I ask.

[Andrew92]

That is quite an interesting study! Do you remember the study I did last year on seasons that occur two years after traditional El Nino years? What I found was those years, since 1960, have always seen at least one hurricane with a pressure no higher than 960 millibars hit the United States. They aren't always category 3 or higher storms, but they all have had large damage potential and have typically pulled it off. Whether right or wrong, this has caused me to come up with my own definition of a major hurricane: one that is either a category 3 hurricane on the Saffir/Simpson Scale (as usual), and/or has a pressure of no higher than 960 millibars. Simply because the damage potential increases greatly at those lower pressures. Sandy is a great example of this, being a category 1 storm upon impacting the northeast, but having a pressure in the 940's. Other recent storms that fit my definition but did not hit the US as category 3 or higher include Gustav, Ike, and Irene.

The other piece I came up with, albeit in a very small sample size, is that one year after Modoki El Nino years have seen at least one major hurricane hit the United States (by my definition), and usually on the Gulf Coast. However, Modoki years I came up with since 1960 have only include 1963, 1969, 2004, and maybe 2012. 1964 had Hilda, 1970 Celia, and 2005 Dennis, Katrina, Rita, and Wilma. I know some say last year wasn't much of an El Nino, but it always seemed like there were some sort of Nino-ish conditions last year, since most of the storms that did intensify did so north of 20 or 25 degrees latitude, until later in the year. Even though 19 storms formed and 10 became hurricanes, only 2 became major hurricanes... since 1995 that is below average and indicative of something going on. I do also seem to remember the eastern equatorial Pacific in the first half as have warmer sea surface temperatures than normal, but then perhaps those warm anomalies shifted west.

I am already nervous enough about this year's hurricane season. Not to be an alarmist over next year, as we have to do this year first, but if this year turns Modoki my theory could very well be put to the test again. So let's not get this year to be a Modoki!

I would therefore be very intrigued to see if this IOD has had anything to with why major hurricanes always strike in the second year after a traditional El Nino. This might give more beef to the study I put together last year.

I didn't mean to hijack this with my own study again. I think what you shared is great information and maybe the study I put together last year with what you are putting together can help us understand how and why this happens. And I'm not even a meteorologist!

-Andrew92

[chaser1]

I have just recently found an interesting "coincidence....
....a cool Indian Ocean and a "Modoki"-type SSTA configuration, the Bermuda High might tend to shift farther south and west. I also looked specifically at neutral-warm years—years which, on the balance, were biased neutral-warm in NINO 3, 3.4, and 4.
....1919, 1928, 1965, and 2004. Two other examples, though less clear, were 1929 and 1935. All those years, inclusive, featured all the strongest landfalls in South FL and/or the Central Gulf Coast.....the possible correlation looks interesting....

Very interesting read! It what manner did you find 1929 & 1935 to be less clear (relating to Modoki Pacific region SST warming or less cool Indian Ocean anomolies?)

[MiamiensisWx]

If Chantal misses FL and hits GA or the Carolinas, will the mean weakness under the Bermuda High allow storms later on (in August-September) to curve northwest and thus bypass FL? Some of the analogs being floated around--i.e. 1953, 1961, 1996--had more and stronger hits in the Carolinas than in FL, yet every reputable landfall forecast keeps FL in the bullseye, which makes little sense given the analogs. Wxman57, has your "Florida-centric" outlook changed a bit recently?

[Cyclenall]

That is a neat correlation found, I like these little findings. That is quite ominous if one is living in Florida because this is already on top of a mountain of signals that point to Florida being the target this season of major activity. My 2013 Atlantic prediction was that FL would be the most likely affected and this just strengthens that further. I didn't know about that thing Andrew92 posted either.

If Chantal misses FL and hits GA or the Carolinas, will the mean weakness under the Bermuda High allow storms later on (in August-September) to curve northwest and thus bypass FL?

I'm not sure what you mean by this? The exact configuration of the Bermuda High won't be the same for every scenario (mean weakness or similar) but I'm already doubting this goes past GA personally.

[Andrew92]

In looking at this study some more, one very difficult thing to ignore is that the major strikes have in Florida during these years, except for Charley, all occurred in the month of September. Of course, the year Charley hit also featured Frances and Jeanne anyway in that month. Another eerie thing is, again except for Charley, they all come onshore heading westward or on some kind of west tilt from the Bahamas.

I have to ask what about 1960, the year Donna smashed into the Keys and then Fort Myers, coming along a path like the one I described in September?

Also, what about years featuring a hurricane not quite a major but still coming along that same type of track into Florida? Besides Donna, Andrew (due to not being mentioned per the original post), and the others I have mentioned, in the satellite era this includes:

Dora in 1964
Inez in 1966
David in 1979
Erin in 1995 (though in early August instead of September)
Katrina and Rita in 2005 (though Rita did pass just south admittedly, but close enough to produce significant weather in the Keys)

Were conditions at least somewhat similar in 1960, 1964, 1966, 1979, 1995, and 2005 to what we have for this year and the others? This is indeed a very interesting study! Also coupled with the fact that I have learned how hard it is to get a hurricane on a path like that into Florida.

-Andrew92

[Andrew92]

OH! One other year I just thought of, pre-satellite era. What about 1945? A nasty category 4 hit Miami hard that year, coming on a westward track from the Bahamas in September as well.

-Andrew92