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Atlantic Tropical Action 2011


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You know, I've lost all fondness for high end La Nina events. It just seems like we can't get any landfalls on the continental US with a Nina pattern. This is totally unscientific, but I generally hope for a neutral to slight Nina season. It seems to be a good middle ground between no development and crappy steering.

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You know, I've lost all fondness for high end La Nina events. It just seems like we can't get any landfalls on the continental US with a Nina pattern. This is totally unscientific, but I generally hope for a neutral to slight Nina season. It seems to be a good middle ground between no development and crappy steering.

I totally hear ya. I was kind of thinking the same thing, and-- like you-- I don't have any data to back up this opinion. It just seems like these La Nina seasons always disappoint from a landfall perspective.

Except for hardcore El Ninos, I don't care that much what ENSO state we're in with regard to 'cane season.

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You know, I've lost all fondness for high end La Nina events. It just seems like we can't get any landfalls on the continental US with a Nina pattern. This is totally unscientific, but I generally hope for a neutral to slight Nina season. It seems to be a good middle ground between no development and crappy steering.

Except that the strongest summer Niña ever recorded was 1955. ENSO is not the be all end all for hurricane steering mechanisms.

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Except that the strongest summer Niña ever recorded was 1955. ENSO is not the be all end all for hurricane steering mechanisms.

If you look at ASO, here are the top ten coldest La Nina years since 1871:

1988 1916 1973 1975 1890 1893 1955 1942 1874 1886

2010 would fit in that list as well. 4 of those years are historic in terms of landfalls. You guys just have too short of a memory. :) Give me a strong La Nina anytime... yeah sure it may not work out but your chances for an epic years are greatly enhanced!

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For those more interested in the ENSO relationship with US landfalls, Phillip Klotzbach had a rather comprehensive paper on that topic:

http://tropical.atmos.colostate.edu/Includes/Documents/Publications/klotzbach2011%28us%29.pdf

Seems pretty reasonable from an empirical point of view, since Ninas tend to feature stronger subtropical ridges which steer storms towards the EC. I hadn't seen that paper before, though, so thanks for posting it.

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If you look at ASO, here are the top ten coldest La Nina years since 1871:

1988 1916 1973 1975 1890 1893 1955 1942 1874 1886

2010 would fit in that list as well. 4 of those years are historic in terms of landfalls. You guys just have too short of a memory. :) Give me a strong La Nina anytime... yeah sure it may not work out but your chances for an epic years are greatly enhanced!

2.4 hurricanes per year for the US... not bad... though, SFL gets screwed

post-29-0-45326500-1302023651.gif

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2.4 hurricanes per year for the US... not bad... though, SFL gets screwed

post-29-0-45326500-1302023651.gif

Very interesting, and goes along with what I expected, and happened last year. The typical troughiness over the E. US in strong Nina's starts to recurve everything at the latitude of S. FL, but anything that can pass south of the trough no longer has any forcing to recurve into southwest FL.

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Very interesting, and goes along with what I expected, and happened last year. The typical troughiness over the E. US in strong Nina's starts to recurve everything at the latitude of S. FL, but anything that can pass south of the trough no longer has any forcing to recurve into southwest FL.

Not saying you're wrong, but that is not what I usually think of during Ninas. Here is the H5 correlation to SOI.

LjIZE.gif

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Not saying you're wrong, but that is not what I usually think of during Ninas. Here is the H5 correlation to SOI.

LjIZE.gif

Hmm, there always seems to be a trough whenever a TC is threatning FL. Maybe the pattern is just more changeable during strong Ninas, so the signal of frequent weak troughs dipping pretty far south is canceled out by the signal of frequent strong high pressure behind each cold front?

Or maybe it's just bad luck with the timing of troughs and TCs...

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2.4 hurricanes per year for the US... not bad... though, SFL gets screwed

post-29-0-45326500-1302023651.gif

Screwed?!?! :) I call that watching them all pass by and breathe a sigh of relief :) Cat 1, fine. Any stronger and that can be a royal PITA IMBY!

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For those more interested in the ENSO relationship with US landfalls, Phillip Klotzbach had a rather comprehensive paper on that topic:

http://tropical.atmo...011%28us%29.pdf

I do believe the most important line in the report is near the beginning, which is basically the same conclusion a non-expert would guess is the case with no detailed statistics to work with:

"In general, more active Atlantic basin TC seasons have more landfalling U.S. hurricanes (Gray 1984; Klotzbach andGray 2004)"

Most, if not all the other statistics and indicators, are not definitive enough to draw much of any other conclusion on the probability of a US landfall in a specific upcoming year based on the ENSO cycle at the time. I believe Hurricanes Andrew, Betsy, and Camille all occurred during El Nino situations; which is contrary to the overall probabilities noted in t he report. That short list contains 2 of the 3 cat 5 landfalls in the past 100+ yrs.

IE: flip a coin.

Trying to predict landfall probabilities months in advance is basically trying to predict where the long wave position will mostly be during the August 20th-Oct.20 time period ahead. 90 day forecasts for "warmer than normal" or "colder than normal" temps over certain areas of the country bear probabilities of verification in the 55% range most of the time (60% once in a while), and they are basically a forecast on where the long wave position will average as well. Hence, any seasonal hurricane landfall "sooth saying" has a verification probability in that same 55% range.

And that 55% is tempered even further: as even if there is a general ridge at mid levels along and just off the East Coast as a hurricane approaches, only a tiny weakness in that ridge will allow the hurricane to turn north or re-curve before landfall.

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