2011 ATL Hurricane Season: Coming to an End

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wxman57
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I think he'll lower his prediction by 1, down to 16. And possibly lower it again by the start of the season. New Euro forecast is for higher pressures in the Atlantic, indicating a stronger Bermuda High. That means greater low-level wind shear (not strong, just greater). Actually, very similar to 2008. Fewer storms than 2010 but a greater landfall risk due to the more westerly movement (stronger Bermuda High).

I'm leaning toward 14-15 named storms this season (down from 19 in 2010). Analog years suggest an increased risk to TX/LA and the Carolinas. Greatest risk would be to the islands of the NE Caribbean.

Euro forecast for July-September 2011 Just Issued:
Image

Same forecast from March 2010:
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Season that occur in transition seem to be more active I have noticed. I don't think this season will be as active as 2010, but it will be active. I think a good analog season are 1961, 1969, 1989, and 2008.
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CPC ENSO Update suggests a nuetral La Nina by June. Some very interesting analogs continue to show up as well.
Summary
•La Niña is present across the equatorial Pacific, but continues to weaken.
•Negative subsurface and sea surface temperature anomalies also continue to weaken across the Pacific Ocean.
•ENSO-neutral conditions are expected by June 2011.
http://www.cpc.ncep.noaa.gov/products/a ... ts-web.pdf
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wxman57
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2008 still looks like a very good analog.
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srainhoutx
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JB seems to like 1996 1999 2005 and 2008 analogs...

http://www.weatherbell.com/jb/?paged=2
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srainhoutx
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Accuweather thoughts include early season threats to TX...

http://www.accuweather.com/blogs/news/s ... season.asp
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wxman57
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srainhoutx wrote:JB seems to like 1996 1999 2005 and 2008 analogs...

http://www.weatherbell.com/jb/?paged=2
I can't find that blog posting, srain. What date did he post it?

Edit: Found it - http://www.weatherbell.com/jb/?paged=3

He wasn't necessarily referring to those years as the best analogs for hurricane season, just that there was a similar ENSO trend in April of those years. But I do agree that 2008 looks to be the best analog so far for the 2011 season.
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srainhoutx wrote:The young Dr. Klotzbach and Dr. Gray of CSU fame are scheduled to release another Tropical Season Update for 2011 on April 6th. It will be interesting to see if the December numbers they predicted hold as well as those ominous analog years that raised an eyebrow.
I'll bump this a day early. The Update is due out tomorrow...

http://typhoon.atmos.colostate.edu/Incl ... edule.html
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wxman57
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Thanks, I'd forgotten that Phil was going to update his forecast tomorrow. I predict he'll lower his numbers of 17-9-5 to 16-8-4 on this update. He may end up with only 14 or 15 named storms forecast by the time June rolls around.
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April update is out. He reduced the numbers to 16/9/5 (from 17/9/5):

http://hurricane.atmos.colostate.edu/Fo ... pr2011.pdf

Best analog years 1955, 1996, 1999 and 2008. 2006 was listed as an analog, but an El Nino developed during the peak of the season, something that's not likely this season. I still think 14-15 named storms may be more likely.
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From the CSU Update:
A 47 percent chance that a major hurricane will make landfall on the Gulf Coast from the Florida Panhandle west to Brownsville (the long-term average is 30 percent).
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Ed Mahmoud wrote:Does the WxMan57 sweat shop center for advanced atmospheric research put out a public forecast?
Yes.
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srainhoutx
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wxman57 wrote:April update is out. He reduced the numbers to 16/9/5 (from 17/9/5):

http://hurricane.atmos.colostate.edu/Fo ... pr2011.pdf

Best analog years 1955, 1996, 1999 and 2008. 2006 was listed as an analog, but an El Nino developed during the peak of the season, something that's not likely this season. I still think 14-15 named storms may be more likely.
Attachments
04062011 1955_Atlantic_hurricane_season_map.png
04062011 1996_Atlantic_hurricane_season_map.png
04062011 1999_Atlantic_hurricane_season_map.png
04062011 2008_Atlantic_hurricane_season_map.png
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Analogs
1955 12/9/6 199
1996 13/9/6 166
1999 12/8/5 177
2006 10/5/2 78
2008 16/8/5 144

Total number can range from 10 to 16, while hurricanes can range from 5 to 9, and there could be 2 to 6 major hurricanes. The ACE ranges from 78 to 199. 2006 occurred when an El Nino develops unexpectedly. 2006 was predicted to be an active season on heels of 2005. All the analogs had a La Nina winter including 2006. 1955, 1999, and 2008 had persistent La Nina. 1996 went into Neutral.

Mean
12.6/7.8/4.8 152.8
13/8/5 153

Median
12/8/5 166

Standard Deviation
2.2/1.6/1.6 46.3
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TSR 14/8/4 124
AccuWX 15/8/3
CSU 16/9/5 160

Mean
15/8/4 142

Median
15/8/4 142

Standard Deviation
1/0.6/1 25.5
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I was looking at TS and hurricane impacts for Klotzbach's analog years (1955, 1996, 1999 and 2008). He listed 2006 as a spring analog, but 2006 went El Nino during the season so he doesn't think 2006 will be a good analog for 2011.

What I plotted below is all hurricane landfalls for 1955, 1996, 1999 and 2008. Some storms made multiple landfalls, so each is indicated. Note the lack of landfalls in Florida, with the exception of Irene in 1999. Even when I plotted TS impacts, there were very few in Florida in the analog years.

Image

An examination of the data reveals a general track pattern that is common in the analog years. The pattern appears to be one set that moves across the NE Caribbean then heads for the Bahamas and the Carolinas. The second path is similar to start with, but continues westward toward the Yucatan Channel then WNW toward either Mexico or south Texas.

The pattern is suggestive of a high pressure area over the central U.S. with a trof in the eastern U.S. It's actually somewhat close to the 2010 pattern, but with a weaker ridge over the U.S. and a stronger Bermuda High. The effect would be to increase the risk of a landfall in the NE Caribbean, the Carolinas, and the western Gulf, as indicated in my graphic below. I don't see the heightened risk to Florida indicated in any of the analog years - UNLESS the Bermuda high is even stronger. Think 1999's Floyd turning north a few hundred miles farther west.

Image
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^
I see you stated 1955 in the opening statement and then changed to 1995 in the next paragragh when discussing analogs. Was that a typo? Regardless, we know that analog tracks of the past can be indicators of possible pattern similarities, but does not suggest these will be the track and storm strengths we can expect. Those finer details cannot be known at this time. With that said, the potential impacts on the Caribbean, MX and the US do look a bit more ominous than last season. I suspect we will have many a long days and nights ahead as we continue to transition toward Tropical Season 2011.
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wxman57
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Yes, that 1995 should read 1955 (fixed it). Analog years aren't "the law" as far as paths for 2011. They just suggest patterns that might be observed as far as development and movement. There are so many variables involved in determining where a hurricane eventually makes landfall. A small pocket of shear that develops in the mid Atlantic east of the Caribbean may delay development of a disturbance for a day. That delay in development might mean the difference in a Florida or East U.S. Coast hit or a Bermuda hit. Timing is everything. No one is safe from a possible impact because of any pattern indicated by analog years.
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I like the way mark Sudduth relays information - no hype, matter-of-fact kind of way

http://www.hurricanetrack.com/

Basically; "you should have your act together, always, to the degree you can afford to do so" 8-)
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The ECMWF Ensembles suggest a nice Bermuda Ridge developing...
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